Could utrophin rescue the myocardium of patients with dystrophin gene mutations?

The spontaneous up-regulation of utrophin, observed in dystrophin-deficient skeletal muscle fibers, may decrease the susceptibility of such fibers to necrosis. It has been reported that the utrophin-rescued double-mutant mdx mouse always develops a lethal cardiomyopathy. We report two patients with severe dilated cardiomyopathy due to dystrophin gene mutations: the first was a manifesting Duchenne muscular dystrophy carrier and the second a patient affected with moderate Becker muscular dystrophy. We studied their explanted heart specimen and/or endoImyocardial biopsies by immunohistochemistry and Western blot for both dystrophin and utrophin. Utrophin was found to be over-expressed in these specimens. Our results suggest that in these patients the up-regulation of utrophin in dystrophin-deficient cardiomyocytes was unable to prevent the development of life-threatening myocardial dysfunction. These findings seem to dampen the enthusiasm raised by the prospect of DMD treatment by utrophin rescue in skeletal muscle fibers, as the myocardium would still remain severely affected.

The spontaneous

    up-regulation of utrophin
    GENETICS

, observed in

    dystrophin-deficient skeletal muscle fibers
    MICROSCOPIC

, may decrease the susceptibility of such fibers to necrosis. It has been reported that the

    utrophin-rescued double-mutant
    GENETICS

 mdx mouse always develops a

    lethal cardiomyopathy
    SYMPTOMS

. We report two patients with

    severe dilated cardiomyopathy
    DIAGNOSIS

 due to

    dystrophin gene mutations
    GENETICS

: the first was a manifesting

    Duchenne muscular dystrophy
    DIAGNOSIS

 carrier and the second a patient affected with

    moderate Becker muscular dystrophy
    DIAGNOSIS

. We studied their

    explanted heart specimen and/or endoImyocardial biopsies
    PARACLINICAL

 by

    immunohistochemistry and Western blot for both dystrophin and utrophin
    PARACLINICAL

.

    Utrophin was found to be over-expressed in these specimens
    MICROSCOPIC

. Our results suggest that in these patients the

    up-regulation of utrophin in dystrophin-deficient cardiomyocytes
    BIOCHEMICAL

    was unable to prevent the development of life-threatening myocardial dysfunction
    NEG_FINDINGS

. These findings seem to dampen the enthusiasm raised by the prospect of

    DMD
    MEDICATION

 treatment by

    utrophin rescue in skeletal muscle fibers
    MEDICATION

, as the

    myocardium would still remain severely affected
    SYMPTOMS

.

up-regulation of utrophin
utrophin-rescued double-mutant
dystrophin gene mutations

severe dilated cardiomyopathy
Duchenne muscular dystrophy
moderate Becker muscular dystrophy


Prenatal evaluation of a de novo X;9 translocation.

A case of X-autosome translocation was diagnosed prenatally [46,X, t(X;9)(p21.3 approximately 22.1;q22]. We describe the use of fluorescence in situ hybridization (FISH) to estimate the integrity of the Duchenne muscular dystrophy (DMD) gene. X-inactivation studies were used as well to assess the probability of phenotypic abnormalities associated with functional partial disomy X and monosomy 9.

A case of

    X-autosome translocation
    GENETICS

 was diagnosed

    prenatally
    AGE

 [

    46,X, t(X;9)(p21.3 approximately 22.1;q22]
    GENETICS

. We describe the use of

    fluorescence in situ hybridization (FISH)
    PARACLINICAL

 to

    estimate the integrity of the Duchenne muscular dystrophy (DMD) gene
    PARACLINICAL

.

    X-inactivation studies
    PARACLINICAL

 were used as well to assess the probability of

    phenotypic abnormalities
    SYMPTOMS

 associated with

    functional partial disomy X and monosomy 9.
    GENETICS


In utero fetal muscle biopsy: a precious aid for the prenatal diagnosis of Duchenne muscular dystrophy.

Prenatal diagnosis for Duchenne muscular dystrophy can usually be performed using DNA analysis. This approach would be impossible when there is only one prior affected male and no identifiable gene deletion. Therefore, in utero fetal thigh muscle biopsy with direct examination of muscle by dystrophin analysis may provide the only means of prenatal diagnosis. We report such a case in which fetal muscle biopsy was able to exclude Duchenne muscular dystrophy. A detailed literature review of the topic is provided.

    Prenatal diagnosis
    PARACLINICAL

 for

    Duchenne muscular dystrophy
    DIAGNOSIS

 can usually be performed using

    DNA analysis
    PARACLINICAL

. This approach would be impossible when there is only one prior affected

    male
    GENDER

 and

    no identifiable gene deletion
    NEG_FINDINGS

. Therefore,

    in utero fetal thigh muscle biopsy
    PARACLINICAL

 with

    direct examination of muscle by dystrophin analysis
    PARACLINICAL

 may provide the only means of

    prenatal diagnosis
    PARACLINICAL

. We report such a case in which

    fetal muscle biopsy
    PARACLINICAL

 was able to exclude

    Duchenne muscular dystrophy
    NEG_FINDINGS

. A detailed literature review of the topic is provided.

no identifiable gene deletion
Duchenne muscular dystrophy


Characterization of two nonsense mutations in the human dystrophin gene.

Forty Duchenne muscular dystrophy patients from the province of Moravia in the Czech Republic, who were previously found negative for large deletions in the dystrophin gene, were tested for the presence of point mutations in selected exons. Besides several intron and exon polymorphisms, two cases of nonsense mutations were detected in exon 70, thus causing the loss of the C-terminal domain of dystrophin. One of these, the mutation, S3365X, is newly reported here while the other, R3381X, has been described previously. These mutations, only 16 bp distant from each other, have a very different impact on the mental abilities of the corresponding patients.

Forty

    Duchenne muscular dystrophy
    DIAGNOSIS

 patients from the province of

    Moravia
    ETHNICITY

 in the

    Czech Republic
    ETHNICITY

, who were previously found

    negative for large deletions in the dystrophin gene
    NEG_FINDINGS

, were tested for the presence of

    point mutations in selected exons
    GENETICS

. Besides several

    intron and exon polymorphisms
    GENETICS

, two cases of

    nonsense mutations
    GENETICS

 were detected

    in exon 70, thus causing the loss of the C-terminal domain of dystrophin
    GENETICS

. One of these, the

    mutation, S3365X
    GENETICS

, is newly reported here while the other,

    R3381X
    GENETICS

, has been described previously. These

    mutations, only 16 bp distant from each
    GENETICS

 other, have a very different impact on the mental abilities of the corresponding patients.


Newly recognized exons induced by a splicing abnormality from an intronic mutation of the dystrophin gene resulting in Duchenne muscular dystrophy. Mutations in brief no. 213. Online.

A boy with the clinical phenotype of Duchenne muscular dystrophy had no detectable deletion or duplication in the dystrophin gene by the routine multiplex PCR method. In mRNA extracted from his muscle biopsy, newly recognized extra-exons of 172 bp and 202 bp were present between exon 25 and 26 suggesting a splicing abnormality. Genomic DNA of the intron 25 including the above insertions were amplified and sequenced. There was one nucleotide substitution of A-to-G at 2 Kb downstream from the 5' end of intron 25 which formed consensus dinucleotide 'GT' motif for 5' splice site resulting in aberrant splicing. This is the first patient who had a mutation at the central part of an intron of the dystrophin gene instead of at the exon-intron border.

A

    boy
    GENDER

 with the clinical phenotype of

    Duchenne muscular dystrophy
    DIAGNOSIS

 had

    no detectable deletion or duplication in the dystrophin gene
    NEG_FINDINGS

 by the

    routine multiplex PCR method
    NEG_FINDINGS

. In

    mRNA extracted from his muscle biopsy
    PARACLINICAL

,

    newly recognized extra-exons of 172 bp and 202 bp were present between exon 25 and 26
    GENETICS

 suggesting a

    splicing abnormality
    GENETICS

.

    Genomic DNA of the intron 25 including the above insertions
    PARACLINICAL

    were amplified and sequenced
    PARACLINICAL

. There was

    one nucleotide substitution of A-to-G at 2 Kb downstream from the 5' end of intron 25 which formed consensus dinucleotide 'GT' motif for 5' splice site resulting in aberrant splicing
    GENETICS

. This is the first patient who had a

    mutation at the central part of an intron of the dystrophin gene instead of at the exon-intron border.
    GENETICS


Cardiac transplantation in a Duchenne muscular dystrophy carrier.

We report here for the first time the case of a symptomatic DMD carrier, who had a heart transplant for a severe dilated cardiomyopathy. Dystrophin immunohistochemistry, western blot and analysis of X-chromosome inactivation on leucocytes, and skeletal and cardiac muscle biopsies on the explanted heart were performed. The patient was a heterozygote for exons 50-52 deletion in the dystrophin gene. The number of dystrophin-deficient fibres in the heart was much higher than in skeletal muscle. On the other hand, the explanted heart showed a non-skewed pattern of X-chromosome inactivation, as in leukocytes and skeletal muscle. The adverse cardiac course may be explained by the absence of regeneration among cardiomyocytes.

We report here for the first time the case of a symptomatic

    DMD
    DIAGNOSIS

 carrier, who had a

    heart transplant
    MEDICATION

 for a

    severe dilated cardiomyopathy
    DIAGNOSIS

.

    Dystrophin immunohistochemistry
    PARACLINICAL

,

    western blot
    PARACLINICAL

 and

    analysis of X-chromosome inactivation on leucocytes
    PARACLINICAL

, and

    skeletal and cardiac muscle biopsies on the explanted heart
    PARACLINICAL

 were performed. The patient was a

    heterozygote for exons 50-52 deletion in the dystrophin gene
    GENETICS

. The

    number of dystrophin-deficient fibres in the heart was much higher than in skeletal muscle
    MICROSCOPIC

. On the other hand, the

    explanted heart
    SYMPTOMS

 showed a

    non-skewed pattern of X-chromosome inactivation, as in leukocytes and skeletal muscle
    GENETICS

. The

    adverse cardiac course
    SYMPTOMS

 may be explained by the

    absence of regeneration among cardiomyocytes
    NEG_FINDINGS

.


[Excess caloric intake induced severe hypercapnia in a patient with Duchenne muscular dystrophy on noninvansive positive pressure ventilation].

In many patients with neuromuscular diseases, respiratory failure is mainly caused by alveolar hypoventilation in their terminal stages. Malnutrition is one of the common and serious problems in patients with chronic respiratory failure. Energy consumption for breathing is remarkably high in respiratory compromised patients, causing subsequent increase of total energy expenditure. However, most patients have limited capacity of oral intake. Nutritional depletion is associated with wasting of respiratory muscles, impairment of respiratory drive, alteration of respiratory pattern, and pathological change of pulmonary parenchyma. These indicate that nutritional and ventilatory support is very important in these patients. However, overfeeding also may have detrimental influence on respiratory failure. We experienced a Duchenne muscular dystrophy (DMD) patient on noninvasive positive pressure ventilation (NIPPV) who developed hypercapnia after total parenteral nutrition (TPN). Analysis of clinical course of this patient revealed that there is a significant correlation between PaCO2 and caloric intake. Excess carbohydrate intake can precipitate fat synthesis which induces over-production of carbon dioxide (CO2). Since NIPPV doesn't have a closed circuit, there are some difficulties in respiratory management, such as air leakage to stomach and mouth, and airway obstruction. Failure to optimize NIPPV setting against increased CO2 load might cause hypercapnia in this patient. These suggest that evaluation of energy expenditure and design of nutritional program are essential to avoid hypercapnia due to nutritional support.

In many patients with

    neuromuscular diseases
    DIAGNOSIS

,

    respiratory failure
    SYMPTOMS

 is mainly caused by

    alveolar hypoventilation
    SYMPTOMS

 in their terminal stages.

    Malnutrition
    DIAGNOSIS

 is one of the common and serious problems in patients with

    chronic respiratory failure
    DIAGNOSIS

.

    Energy consumption for breathing
    BIOCHEMICAL

 is remarkably high in

    respiratory compromised
    SYMPTOMS

 patients, causing subsequent

    increase of total energy expenditure
    BIOCHEMICAL

. However, most patients have

    limited capacity of oral intake
    NEG_FINDINGS

.

    Nutritional depletion
    BIOCHEMICAL

 is associated with

    wasting of respiratory muscles
    SYMPTOMS

,

    impairment of respiratory drive
    SYMPTOMS

,

    alteration of respiratory pattern
    SYMPTOMS

, and

    pathological change of pulmonary parenchyma
    SYMPTOMS

. These indicate that

    nutritional and ventilatory support
    MEDICATION

 is very important in these patients. However,

    overfeeding
    SYMPTOMS

 also may have detrimental influence on

    respiratory failure
    SYMPTOMS

. We experienced a

    Duchenne muscular dystrophy (DMD)
    DIAGNOSIS

 patient on

    noninvasive positive pressure ventilation (NIPPV)
    MEDICATION

 who developed

    hypercapnia
    SYMPTOMS

 after

    total parenteral nutrition (TPN)
    MEDICATION

. Analysis of clinical course of this patient revealed that there is a significant correlation between

    PaCO2 and caloric intake
    BIOCHEMICAL

.

    Excess carbohydrate intake
    BIOCHEMICAL

 can

    precipitate fat synthesis
    BIOCHEMICAL

 which induces

    over-production of carbon dioxide (CO2)
    BIOCHEMICAL

. Since

    NIPPV
    MEDICATION

 doesn't have a closed circuit, there are some difficulties in respiratory management, such as

    air leakage to stomach and mouth
    SYMPTOMS

, and

    airway obstruction
    SYMPTOMS

.

    Failure to optimize NIPPV setting against increased CO2 load
    NEG_FINDINGS

 might cause

    hypercapnia
    SYMPTOMS

 in this patient. These suggest that

    evaluation of energy expenditure
    PARACLINICAL

 and design of

    nutritional program
    MEDICATION

 are essential to avoid

    hypercapnia
    SYMPTOMS

 due to

    nutritional support
    MEDICATION

.

neuromuscular diseases
Malnutrition
chronic respiratory failure
Duchenne muscular dystrophy (DMD)

Energy consumption for breathing
increase of total energy expenditure
Nutritional depletion
PaCO2 and caloric intake
Excess carbohydrate intake
precipitate fat synthesis
over-production of carbon dioxide (CO2)


Pitfalls in prenatal diagnosis of DMD due to placental mosaicism of the X-chromosomes: prenatal and postnatal findings in a fetus with a deletion of exons 67-71 of the dystrophin gene.

Prenatal diagnosis of Duchenne and Becker muscular dystrophy (DMD) is performed as a routine procedure in many laboratories. The major potential problem is an incorrect diagnosis that could be obtained due to contamination with maternal tissue. We report a case of mosaicism of the X-chromosomes confined to the placenta as a possible source of confusing results in prenatal diagnosis of DMD. To the best of our knowledge, this is the first reported case of this problem in a prenatal DMD diagnosis.

    Prenatal diagnosis
    PARACLINICAL

 of

    Duchenne and Becker muscular dystrophy (DMD)
    DIAGNOSIS

 is performed as a routine procedure in many laboratories. The major potential problem is an incorrect diagnosis that could be obtained due to

    contamination with maternal tissue
    MICROSCOPIC

. We report a case of

    mosaicism of the X-chromosomes confined to the placenta
    GENETICS

 as a possible source of confusing results in

    prenatal diagnosis
    PARACLINICAL

 of

    DMD
    DIAGNOSIS

. To the best of our knowledge, this is the first reported case of this problem in a

    prenatal DMD
    AGE

 diagnosis.


[Treatment of nocturnal periodic hypoxemia with safrazine hydrochloride in a patient with Duchenne muscular dystrophy under nasal intermittent positive pressure ventilation].

Nocturnal periodic hypoxemia occurring in a 25-year-old Duchenne muscular dystrophy patient under NIPPV control was successfully treated with monoamine oxydase inhibitor (MAOI), safrazine hydrochloride. Five mg of safrazine hydrochloride was administered before sleep, and the periodic hypoxemia disappeared within 14 days. The effect lasted almost seven months without notable side effect. MAOI may be effective for nocturnal hypoventilation through suppression of REM sleep as in the case of tricyclic antidepressants. The effect of tricyclic antidepressants appears immediately. However, it usually fades away within forty days. Safrazine hydrochloride was effective obviously longer than tricyclic antidepressants. Consequently MAOI may be a hopeful candidate of medication for a treatment of nocturnal periodic hypoxemia in Duchenne muscular dystrophy.

    Nocturnal periodic hypoxemia
    SYMPTOMS

 occurring in a

    25-year-old
    AGE

    Duchenne muscular dystrophy
    DIAGNOSIS

 patient under

    NIPPV control
    MEDICATION

 was successfully treated with

    monoamine oxydase inhibitor (MAOI), safrazine hydrochloride
    MEDICATION

.

    Five mg of safrazine hydrochloride
    MEDICATION

 was administered before sleep, and the

    periodic hypoxemia
    SYMPTOMS

 disappeared within 14 days. The effect lasted almost seven months

    without notable side effect
    NEG_FINDINGS

.

    MAOI
    MEDICATION

 may be effective for

    nocturnal hypoventilation
    SYMPTOMS

 through

    suppression of REM sleep
    BIOCHEMICAL

 as in the case of

    tricyclic antidepressants
    MEDICATION

. The effect of

    tricyclic antidepressants
    MEDICATION

 appears immediately. However, it usually fades away within forty days.

    Safrazine hydrochloride
    MEDICATION

 was effective obviously longer than

    tricyclic antidepressants
    MEDICATION

. Consequently

    MAOI
    MEDICATION

 may be a hopeful candidate of medication for a treatment of

    nocturnal periodic hypoxemia
    SYMPTOMS

 in

    Duchenne muscular dystrophy
    DIAGNOSIS

.

Nocturnal periodic hypoxemia
periodic hypoxemia
nocturnal hypoventilation
nocturnal periodic hypoxemia

Duchenne muscular dystrophy
Duchenne muscular dystrophy


Muscle fiber immaturity and inactivity reduce myonecrosis in Duchenne muscular dystrophy.

We report on the first case of X-linked recessive myotubular myopathy (MTM1) coinciding with Duchenne muscular dystrophy (DMD). The muscle biopsy specimens of the patient show only the characteristic findings of MTM1, without the findings of DMD. We theorize that this was caused by the muscle fiber immaturity and inactivity.

We report on the first case of

    X-linked recessive myotubular myopathy (MTM1)
    GENETICS

 coinciding with

    Duchenne muscular dystrophy (DMD)
    DIAGNOSIS

. The

    muscle biopsy specimens
    PARACLINICAL

 of the patient show only the characteristic

    findings of MTM1
    MICROSCOPIC

,

    without the findings of DMD
    NEG_FINDINGS

. We theorize that this was caused by the

    muscle fiber immaturity
    SYMPTOMS

 and

    inactivity
    SYMPTOMS

.


Triplet pregnancy with acardius acranius after preimplantation diagnosis.

To report the first case of fetal malformation after preimplantation diagnosis for Duchenne muscular dystrophy (DMD).

Case report.

Perinatal center in a university hospital.

A conductor for DMD in her third pregnancy.

Preimplantation diagnosis was performed in an outside hospital. In our center, a dichorionic triplet pregnancy with acardius acranius was diagnosed. The anastomosis between the "pump"-twin and the fetus with acardius was embolized with histoacryl to prevent worsening cardiac insufficiency of the "pump"-twin.

Pregnancy outcome.

The anastomosis between the "pump"-twin and the fetus with acardius was occluded successfully. Premature preterm rupture of membranes led to rapid labor and delivery at 24 + 5 weeks' gestation. The smaller girl died of severe hyaline membrane disease, whereas the other infant had no major clinical problems and has developed well.

There might be an association between embryo biopsy and fetal malformations. The setting up of a birth register after embryo biopsy is strongly recommended.

To report the first case of

    fetal malformation
    SYMPTOMS

 after

    preimplantation diagnosis
    MEDICATION

 for

    Duchenne muscular dystrophy (DMD)
    DIAGNOSIS

.

    Perinatal center in a university hospital
    MEDICATION

.

A

    conductor for DMD in her third pregnancy
    MEDICATION

.

    Preimplantation diagnosis
    PARACLINICAL

 was performed in an outside hospital. In our center, a

    dichorionic triplet pregnancy with acardius acranius
    DIAGNOSIS

 was diagnosed.

    The anastomosis between the "pump"-twin and the fetus with acardius
    MEDICATION

    was embolized with histoacryl
    MEDICATION

 to prevent

    worsening cardiac insufficiency of the "pump"-twin
    SYMPTOMS

.

    The anastomosis between the "pump"-twin and the fetus with acardius
    MEDICATION

    was occluded
    MEDICATION

 successfully.

    Premature preterm rupture of membranes
    SYMPTOMS

 led to

    rapid labor and delivery at 24 + 5 weeks' gestation
    MEDICATION

. The smaller

    girl
    GENDER

    died
    SYMPTOMS

 of

    severe hyaline membrane disease
    DIAGNOSIS

, whereas the other

    infant
    AGE

 had

    no major clinical problems
    NEG_FINDINGS

 and has developed well.

There might be an association between

    embryo biopsy
    PARACLINICAL

 and

    fetal malformations
    SYMPTOMS

. The setting up of a birth register after

    embryo biopsy
    PARACLINICAL

 is strongly recommended.


Laminin alpha 2-chain gene mutations in two siblings presenting with limb-girdle muscular dystrophy.

We report two siblings, an 11-year-old boy and his 7-year-old sister, referred to us with a diagnosis of muscular dystrophy. The boy presented at 22 months with delay in walking. A very high serum creatine kinase (CK) level and a dystrophic muscle biopsy lead to a diagnosis of Duchenne muscular dystrophy prior to the identification of the dystrophin gene. Two years later his sister presented with similar problems. A diagnosis of limb-girdle muscular dystrophy was made when they were shown to have inherited different X-chromosomes and normal expression of dystrophin and all sarcoglycans. Their conditions remained static. Recently a slowing of the peripheral motor nerve conduction velocities and T2-weighted brain magnetic resonance imaging showed increased signal of the white matter, both of which are features of merosin-deficient congenital muscular dystrophy. Immunolabelling using a C-terminal laminin alpha 2 chain antibody showed a reduction in expression, while labelling with another antibody that recognises a 300-kDa fragment showed a very significant reduction. Mutational analysis of the LAMA2 gene showed two mutations: one was a G-->C point mutation at position -1 of intron 28 acceptor splicing site. This mutation induced activation of a cryptic splice at nucleotide 4429 of exon 29 and partial skipping of this exon, with conservation of the open reading frame. The other was a nonsense mutation due to a C_T transition at position 5525 of the cDNA sequence (exon 37), resulting in a stop codon. These data confirm that mutations of the LAMA2 gene that do not completely disrupt the production of the protein can give rise to phenotypes considerably milder than classical merosin-deficient congenital muscular dystrophy. Partial laminin alpha 2 deficiency should be considered in the differential diagnosis of limb-girdle muscular dystrophy.

We report two siblings, an

    11-year-old
    AGE

    boy
    GENDER

 and his

    7-year-old
    AGE

    sister
    FAMILY

, referred to us with a diagnosis of

    muscular dystrophy
    DIAGNOSIS

. The

    boy
    GENDER

 presented

    at 22 months
    AGE

 with

    delay in walking
    SYMPTOMS

. A

    very high serum creatine kinase (CK) level
    BIOCHEMICAL

 and a

    dystrophic muscle biopsy
    PARACLINICAL

 lead to a diagnosis of

    Duchenne muscular dystrophy
    DIAGNOSIS

 prior to the identification of the dystrophin gene. Two years later

    his sister presented with similar problems
    FAMILY

. A diagnosis of

    limb-girdle muscular dystrophy
    DIAGNOSIS

 was made when they were shown to have

    inherited different X-chromosomes
    GENETICS

 and

    normal expression of dystrophin and all sarcoglycans
    NEG_FINDINGS

. Their

    conditions remained static
    SYMPTOMS

. Recently a

    slowing of the peripheral motor nerve conduction velocities
    SYMPTOMS

 and

    T2-weighted brain magnetic resonance imaging
    PARACLINICAL

 showed

    increased signal of the white matter
    SYMPTOMS

, both of which are features of

    merosin-deficient congenital muscular dystrophy
    DIAGNOSIS

.

    Immunolabelling
    PARACLINICAL

 using a

    C-terminal laminin alpha 2 chain antibody
    BIOCHEMICAL

 showed a

    reduction in expression
    BIOCHEMICAL

, while labelling with another antibody that recognises a 300-kDa fragment showed a

    very significant reduction
    BIOCHEMICAL

.

    Mutational analysis of the LAMA2 gene
    PARACLINICAL

 showed two mutations: one

    was a G-->C point mutation at position -1 of intron 28 acceptor splicing site. This mutation induced activation of a cryptic splice at nucleotide 4429 of exon 29 and partial skipping of this exon, with conservation of the open reading frame
    GENETICS

. The other was a

    nonsense mutation due to a C_T transition at position 5525 of the cDNA sequence (exon 37), resulting in a stop codon
    GENETICS

. These data confirm that

    mutations of the LAMA2 gene
    GENETICS

 that

    do not completely disrupt the production of the protein
    NEG_FINDINGS

 can give rise to

    phenotypes considerably milder than classical merosin-deficient congenital muscular dystrophy
    SYMPTOMS

.

    Partial laminin alpha 2 deficiency
    BIOCHEMICAL

 should be considered in the

    differential diagnosis
    PARACLINICAL

 of

    limb-girdle muscular dystrophy
    DIAGNOSIS

.


Dystrophinopathy in a boy with Chediak-Higashi syndrome.

Chediak-Higashi syndrome (CHS) is a hereditary, biphasic immunodeficiency syndrome which usually leads to early death, during the first decade. The second phase is characterized by a lymphoproliferative syndrome with histiocytic infiltrations in various tissues. Recently the gene has been identified on chromosome 1q43. In the patient presented here, a mutation within codon 3197 was found, resulting in a frame-shift. Additionally, Duchenne muscular dystrophy (DMD) was diagnosed by immunostaining of the muscle. Unusual for both CHS and DMD muscle weakness and hypotonia became evident during the first months of life. Compared to typical DMD cases we found an increased histiocytic infiltration in the muscle. The underlying muscular dystrophy probably predisposes to the affection of muscle in the second phase of CHS. This patient is presented as an example of modification of the phenotype by a second genetic disease.

    Chediak-Higashi syndrome (CHS)
    DIAGNOSIS

 is a

    hereditary
    GENETICS

,

    biphasic immunodeficiency syndrome
    DIAGNOSIS

 which usually leads to

    early death
    SYMPTOMS

,

    during the first decade
    AGE

. The second phase is characterized by a

    lymphoproliferative syndrome
    DIAGNOSIS

 with

    histiocytic infiltrations in various tissues
    MICROSCOPIC

. Recently the gene has been identified on

    chromosome 1q43
    GENETICS

. In the patient presented here, a

    mutation within codon 3197 was found, resulting in a frame-shift
    GENETICS

. Additionally,

    Duchenne muscular dystrophy (DMD)
    DIAGNOSIS

 was diagnosed by

    immunostaining of the muscle
    PARACLINICAL

. Unusual for both

    CHS
    DIAGNOSIS

 and

    DMD
    DIAGNOSIS

    muscle weakness
    SYMPTOMS

 and

    hypotonia
    SYMPTOMS

 became evident

    during the first months of life
    AGE

. Compared to typical

    DMD
    DIAGNOSIS

 cases we found an

    increased histiocytic infiltration in the muscle
    MICROSCOPIC

. The underlying

    muscular dystrophy
    DIAGNOSIS

 probably predisposes to the

    affection of muscle
    SYMPTOMS

 in the second phase of

    CHS
    DIAGNOSIS

. This patient is presented as an example of modification of the phenotype by a

    second genetic disease
    GENETICS

.

Chediak-Higashi syndrome (CHS)
biphasic immunodeficiency syndrome
lymphoproliferative syndrome
Duchenne muscular dystrophy (DMD)
CHS
DMD
DMD
muscular dystrophy
CHS

early death
muscle weakness
hypotonia
affection of muscle


Preimplantation genetic diagnosis of spinal muscular atrophy.

After Duchenne muscular dystrophy, spinal muscular atrophy (SMA) is the most common severe neuromuscular disease in childhood. Since 1995, homozygous deletions in exon 7 of the survival motor neuron (SMN) gene have been described in >90-95% of SMA patients. However, the presence of a highly homologous SMN copy gene complicates the detection of exon 7 deletions. This paper describes the adjustment and evaluation of an established SMN exon 7 polymerase chain reaction (PCR) protocol at the single cell level, and the first preimplantation genetic diagnosis (PGD) of SMA with this PCR protocol. To determine PCR efficiency and allelic loss, 200 leukocytes of normal individuals, SMA carriers and patients, and 25 blastomeres were tested. The PCR efficiency of the SMN exon 7 and the adjacent copy gene sequence, tested in the leukocytes, were 90% and 91% respectively. No allelic loss was detected. One out of 25 blastomeres tested revealed a negative PCR signal for the SMN exon 7 sequence. All 25 showed the copy gene sequence. PGD of SMA was offered to a couple with an affected child homozygous for the SMN exon 7 deletion. After intracytoplasmic sperm injection, four and five embryos could be genotyped for the SMN exon 7 in two cycles respectively. After embryo transfer in the second PGD cycle an ongoing gemelli pregnancy was achieved. This study demonstrates that PGD for SMA is feasible when a previous child is homozygous for the SMN exon 7 deletion.

After

    Duchenne muscular dystrophy
    DIAGNOSIS

,

    spinal muscular atrophy (SMA)
    DIAGNOSIS

 is the most common

    severe neuromuscular disease
    DIAGNOSIS

 in

    childhood
    AGE

. Since 1995,

    homozygous deletions in exon 7 of the survival motor neuron (SMN) gene
    GENETICS

 have been described in >90-95% of

    SMA
    DIAGNOSIS

 patients. However, the presence of a

    highly homologous SMN copy gene
    GENETICS

 complicates the detection of

    exon 7 deletions
    GENETICS

. This paper describes the adjustment and evaluation of an established

    SMN exon 7 polymerase chain reaction (PCR) protocol at the single cell level
    PARACLINICAL

, and the first

    preimplantation genetic diagnosis (PGD)
    MEDICATION

 of

    SMA
    DIAGNOSIS

 with this PCR protocol. To determine PCR efficiency and allelic loss, 200 leukocytes of normal individuals,

    SMA
    DIAGNOSIS

 carriers and patients, and 25 blastomeres were tested. The

    PCR efficiency of the SMN exon 7 and the adjacent copy gene sequence
    PARACLINICAL

, tested in the leukocytes, were 90% and 91% respectively.

    No allelic loss
    NEG_FINDINGS

 was detected. One out of 25 blastomeres tested revealed a

    negative PCR signal for the SMN exon 7 sequence
    NEG_FINDINGS

. All 25 showed the

    copy gene sequence
    GENETICS

.

    PGD of SMA
    MEDICATION

 was offered to a

    couple with an affected child homozygous for the SMN exon 7 deletion
    FAMILY

. After

    intracytoplasmic sperm injection
    MEDICATION

, four and five embryos could be

    genotyped for the SMN exon 7
    PARACLINICAL

 in two cycles respectively. After

    embryo transfer in the second PGD cycle
    MEDICATION

 an

    ongoing gemelli pregnancy
    MEDICATION

 was achieved. This study demonstrates that

    PGD
    MEDICATION

 for

    SMA
    DIAGNOSIS

 is feasible when a

    previous child is homozygous for the SMN exon 7 deletion
    FAMILY

.

Duchenne muscular dystrophy
spinal muscular atrophy (SMA)
severe neuromuscular disease
SMA
SMA
SMA
SMA

preimplantation genetic diagnosis (PGD)
PGD of SMA
intracytoplasmic sperm injection
embryo transfer in the second PGD cycle
ongoing gemelli pregnancy
PGD


Primary alpha-sarcoglycan deficiency responsive to immunosuppression over three years.

An 8-year-old girl developed weakness over 2 years and an elevated creatine kinase. The biopsy was most consistent with an active dystrophy with many inflammatory cells present. A trial of immunosuppression was started. In the first 2 months of treatment with prednisone, she had functionally and quantitatively significant improvement in her proximal strength. Over 3 years of treatment she maintained stable strength. Subsequent genetic studies showed that she had primary alpha-sarcoglycan deficiency. The timing and the degree of benefit in strength were similar to that seen in boys with Duchenne muscular dystrophy who are treated with prednisone.

An

    8-year-old
    AGE

    girl
    GENDER

 developed

    weakness over 2 years
    SYMPTOMS

 and an

    elevated creatine kinase
    BIOCHEMICAL

. The

    biopsy
    PARACLINICAL

 was most consistent with an

    active dystrophy
    DIAGNOSIS

 with

    many inflammatory cells present
    MICROSCOPIC

. A

    trial of immunosuppression
    MEDICATION

 was started. In the first

    2 months of treatment with prednisone
    MEDICATION

,

    she
    GENDER

 had

    functionally and quantitatively significant improvement in her proximal strength
    SYMPTOMS

.

    Over 3 years of treatment
    MEDICATION

    she
    GENDER

    maintained stable strength
    SYMPTOMS

. Subsequent

    genetic studies
    PARACLINICAL

 showed that

    she
    GENDER

 had

    primary alpha-sarcoglycan deficiency
    BIOCHEMICAL

. The timing and the degree of

    benefit in strength
    SYMPTOMS

 were similar to that seen in

    boys
    GENDER

 with

    Duchenne muscular dystrophy
    DIAGNOSIS

 who are treated with

    prednisone
    MEDICATION

.

elevated creatine kinase
primary alpha-sarcoglycan deficiency

active dystrophy
Duchenne muscular dystrophy

trial of immunosuppression
2 months of treatment with prednisone
Over 3 years of treatment
prednisone


[Myocardial involvement in carrier states for Duchenne muscular dystrophy. A rare cause of supraventricular arrhythmia].

Two women, both aged 54 years, were admitted because of supraventricular arrhythmias of recent onset. Patient 2 was also in heart failure. Male family members of both patients were known to have Duchenne's muscular dystrophy, of which one had died.

The electrocardiogram of patient 1 demonstrated atrial fibrillation. Patient 2 had a raised serum creatine kinase concentration and increased pulmonary marking in the chest radiogram. Patient 1 had normal findings on left heart catheterization, but immunohistochemical analysis of a myocardial biopsy revealed dystrophin mosaic with 20% dystrophin-negative fibres. Patient 2 had a reduced ejection fraction and 80% dystrophin-negative fibres.

Myocardial involvement in the carrier state for Duchenne's muscular dystrophy having been demonstrated in both women, patient 1 received antihypertensive treatment while patient 2, who was in cardiac failure, was given diuretics, ACE-inhibitor and beta-receptor blockers.

Cardiomyopathy in carriers of Duchenne's muscular dystrophy is a rare cause of supraventricular arrhythmias. The cause can be confirmed by immunochemical analysis of an endomyocardial biopsy.

Two

    women
    GENDER

, both

    aged 54 years
    AGE

, were admitted because of

    supraventricular arrhythmias of recent onset
    SYMPTOMS

. Patient 2 was also in

    heart failure
    SYMPTOMS

.

    Male family members of both patients were known to have Duchenne's muscular dystrophy
    FAMILY

,

    of which one had died
    FAMILY

.

The

    electrocardiogram
    PARACLINICAL

 of patient 1 demonstrated

    atrial fibrillation
    SYMPTOMS

. Patient 2 had a

    raised serum creatine kinase concentration
    BIOCHEMICAL

 and

    increased pulmonary marking in the chest radiogram
    SYMPTOMS

. Patient 1 had

    normal findings on left heart catheterization
    NEG_FINDINGS

, but

    immunohistochemical analysis of a myocardial biopsy
    PARACLINICAL

 revealed

    dystrophin mosaic with 20% dystrophin-negative fibres
    MICROSCOPIC

. Patient 2 had a

    reduced ejection fraction
    SYMPTOMS

 and

    80% dystrophin-negative fibres
    MICROSCOPIC

.

    Myocardial involvement
    SYMPTOMS

 in the carrier state for

    Duchenne's muscular dystrophy
    DIAGNOSIS

 having been demonstrated in both

    women
    GENDER

, patient 1 received

    antihypertensive treatment
    MEDICATION

 while patient 2, who was in

    cardiac failure
    SYMPTOMS

, was given

    diuretics, ACE-inhibitor and beta-receptor blockers
    MEDICATION

.

    Cardiomyopathy
    DIAGNOSIS

 in carriers of

    Duchenne's muscular dystrophy
    DIAGNOSIS

 is a rare cause of

    supraventricular arrhythmias
    SYMPTOMS

. The cause can be confirmed by

    immunochemical analysis of an endomyocardial biopsy
    PARACLINICAL

.

Duchenne's muscular dystrophy
Cardiomyopathy
Duchenne's muscular dystrophy


Preimplantation diagnosis of non-deletion Duchenne muscular dystrophy (DMD) by linkage polymerase chain reaction analysis.

The use of preimplantation diagnosis for sex determination and detection of exon deletion means that unaffected babies can be born to parents suffering from Duchenne muscular dystrophy (DMD). However, those who do not have exon deletion should also be considered for further investigation. A new method, known as linkage analysis, has been developed to diagnose the presence of non-deletion DMD in preimplantation embryos. Linkage analysis uses informative intragenic and flanking markers to track the chromosome bearing the mutated gene. The present study reports the analysis of two polymorphic sites, in blastomeres biopsied from embryos from a female carrier of DMD. A single male embryo was obtained who had inherited alternate maternal alleles to the woman's affected surviving son, and this embryo was transferred.

The use of

    preimplantation diagnosis
    PARACLINICAL

 for

    sex determination
    PARACLINICAL

 and detection of

    exon deletion
    GENETICS

 means that unaffected babies can be born to

    parents suffering from Duchenne muscular dystrophy (DMD)
    FAMILY

. However, those who do not have

    exon deletion
    NEG_FINDINGS

 should also be considered for further investigation. A new method, known as

    linkage analysis
    PARACLINICAL

, has been developed to diagnose the presence of

    non-deletion DMD
    GENETICS

 in

    preimplantation embryos
    GENETICS

.

    Linkage analysis
    PARACLINICAL

 uses

    informative intragenic and flanking markers
    PARACLINICAL

 to track the

    chromosome bearing the mutated gene
    GENETICS

. The present study reports the

    analysis of two polymorphic sites, in blastomeres biopsied from embryos
    PARACLINICAL

 from a

    female
    GENDER

 carrier of

    DMD
    DIAGNOSIS

. A single

    male
    GENDER

 embryo was obtained who

    had inherited alternate maternal alleles to the woman's affected surviving son
    FAMILY

, and this

    embryo was transferred
    MEDICATION

.

exon deletion
non-deletion DMD
preimplantation embryos
chromosome bearing the mutated gene


Skewed X inactivation in manifesting carriers of Duchenne muscular dystrophy.

We studied X inactivation patterns in manifesting carriers of familial and sporadic Duchenne muscular dystrophy (DMD) or unaffected carriers of DMD by analysis of the methylation of HpaII sites in the first exon of the human androgen-receptor gene (HUMARA) from peripheral blood samples. Three of the four manifesting carriers, four of the five asymptomatic carriers, and 31 of the 32 female controls were heterozygous for the CAG repeat of HUMARA. All manifesting carriers showed skewed X inactivation, while all unaffected carriers showed almost symmetrical inactivation. One family studied over three generations is noteworthy because it includes two mother/daughter pairs, one an affected pair with skewed X inactivation, and the other a phenotypically normal carrier pair with random X inactivation. On the other hand, the extent of X inactivation for each X chromosome in 31 female controls was widely distributed. These data suggest that in carriers of DMD, both affected and unaffected, it is valuable to analyze the pattern of skewed X inactivation because it provides important prognostic information. Carriers of DMD with skewed X inactivation might show slowly progressive myopathy with advancing age.

We studied

    X inactivation patterns
    GENETICS

 in manifesting carriers of

    familial and sporadic Duchenne muscular dystrophy (DMD)
    DIAGNOSIS

 or

    unaffected carriers of DMD
    NEG_FINDINGS

 by

    analysis of the methylation of HpaII sites in the first exon of the human androgen-receptor gene (HUMARA) from peripheral blood samples
    PARACLINICAL

. Three of the four manifesting carriers, four of the five asymptomatic carriers, and 31 of the 32

    female
    GENDER

 controls were

    heterozygous for the CAG repeat of HUMARA
    GENETICS

. All manifesting carriers showed

    skewed X inactivation
    GENETICS

, while all unaffected carriers showed

    almost symmetrical inactivation
    SYMPTOMS

. One

    family studied over three generations
    FAMILY

 is noteworthy because it

    includes two mother/daughter pairs, one an affected pair with skewed X inactivation
    FAMILY

    , and the other a phenotypically normal carrier pair with random X inactivation
    FAMILY

. On the other hand, the

    extent of X inactivation for each X chromosome
    GENETICS

 in 31

    female
    GENDER

 controls was widely distributed. These data suggest that in carriers of

    DMD
    DIAGNOSIS

, both affected and unaffected, it is valuable to analyze the

    pattern of skewed X inactivation
    GENETICS

 because it provides important prognostic information. Carriers of

    DMD
    DIAGNOSIS

 with

    skewed X inactivation
    GENETICS

 might show

    slowly progressive myopathy
    SYMPTOMS

 with advancing

    age
    AGE

.

almost symmetrical inactivation
slowly progressive myopathy


Early presentation of X-linked Emery-Dreifuss muscular dystrophy resembling limb-girdle muscular dystrophy.

Emery-Dreifuss muscular dystrophy is an X-linked neuromuscular disorder caused by defects in the STA gene on Xq28, which codes for a nuclear protein named emerin. Affected patients usually present in early adolescence with scapulo-peroneal muscle weakness and wasting, and contractures of the tendo Achilles, elbows and paraspinal muscles, resulting in spine rigidity. We present here a case of Emery-Dreifuss muscular dystrophy with an unusually severe, early presentation. He presented at 2.5 years with predominantly proximal weakness and mild equinovarus deformity of the right foot. Serum creatine kinase activity was elevated (1994 IU/I) and a muscle biopsy at the age of 4 years showed marked dystrophic abnormalities. Normal expression of dystrophin, and no detectable deletion in the corresponding gene, excluded a diagnosis of Duchenne muscular dystrophy. Similarly, normal expression of alpha-sarcoglycan made a limb-girdle muscular dystrophy caused by a defect in a sarcoglycan unlikely. Several years later, examination of the proband's maternal cousin, aged 14 years, suggested Emery-Dreifuss muscular dystrophy. This was confirmed in both affected boys by the absence of emerin in muscle and leucocytes, and identification of a mutation in exon 4 of the STA gene. Carrier status in both mothers was also confirmed by mutational and protein analysis. Emery-Dreifuss muscular dystrophy should therefore be considered in the differential diagnosis of cases of early onset muscular dystrophy, even in the absence of the typical clinical features.

    Emery-Dreifuss muscular dystrophy
    DIAGNOSIS

 is an

    X-linked
    GENETICS

    neuromuscular disorder
    DIAGNOSIS

 caused by

    defects in the STA gene on Xq28
    GENETICS

, which codes for a nuclear protein named emerin. Affected patients usually present in

    early adolescence
    AGE

 with

    scapulo-peroneal muscle weakness and wasting
    SYMPTOMS

, and

    contractures of the tendo Achilles, elbows and paraspinal muscles
    SYMPTOMS

, resulting in

    spine rigidity
    SYMPTOMS

. We present here a case of

    Emery-Dreifuss muscular dystrophy
    DIAGNOSIS

 with an

    unusually severe, early presentation
    SYMPTOMS

.

    He
    GENDER

 presented

    at 2.5 years
    AGE

 with

    predominantly proximal weakness
    SYMPTOMS

 and

    mild equinovarus deformity of the right foot
    SYMPTOMS

.

    Serum creatine kinase activity was elevated (1994 IU/I)
    BIOCHEMICAL

 and a

    muscle biopsy
    PARACLINICAL

    at the age of 4 years
    AGE

 showed

    marked dystrophic abnormalities
    SYMPTOMS

.

    Normal expression of dystrophin
    NEG_FINDINGS

, and

    no detectable deletion in the corresponding gene
    NEG_FINDINGS

,

    excluded a diagnosis of Duchenne muscular dystrophy
    NEG_FINDINGS

. Similarly,

    normal expression of alpha-sarcoglycan
    NEG_FINDINGS

 made a

    limb-girdle muscular dystrophy
    DIAGNOSIS

 caused by a

    defect in a sarcoglycan unlikely
    NEG_FINDINGS

. Several years later,

    examination of the proband's maternal cousin, aged 14 years
    PARACLINICAL

, suggested

    Emery-Dreifuss muscular dystrophy
    DIAGNOSIS

. This was confirmed in both affected

    boys
    GENDER

 by the

    absence of emerin in muscle and leucocytes
    MICROSCOPIC

, and identification of a

    mutation in exon 4 of the STA gene
    GENETICS

.

    Carrier status in both mothers
    FAMILY

 was also confirmed by

    mutational and protein analysis
    PARACLINICAL

.

    Emery-Dreifuss muscular dystrophy
    DIAGNOSIS

 should therefore be considered in the

    differential diagnosis
    PARACLINICAL

 of cases of

    early onset muscular dystrophy
    DIAGNOSIS

, even in the absence of the typical clinical features.

Emery-Dreifuss muscular dystrophy
neuromuscular disorder
Emery-Dreifuss muscular dystrophy
limb-girdle muscular dystrophy
Emery-Dreifuss muscular dystrophy
Emery-Dreifuss muscular dystrophy
early onset muscular dystrophy

X-linked
defects in the STA gene on Xq28
mutation in exon 4 of the STA gene


Sarcolemmal defect and subsarcolemmal lesion in a patient with gamma-sarcoglycan deficiency.

We report a case of gamma-sarcoglycanopathy with sarcolemmal defects and subsarcolemmal lesions indistinguishable from those in Duchenne muscular dystrophy. Both disorders share certain ultrastructure features that suggest a common pathogenesis related to primary deficiency of transmembrane glycoproteins (e.g., sarcoglycans) or deficiency in dystrophin, which produces a secondary deficiency in sarcoglycans. The lack of transmembrane glycoproteins may contribute to membrane lesions and associated muscle fiber degeneration and necrosis.

We report a case of

    gamma-sarcoglycanopathy
    DIAGNOSIS

 with

    sarcolemmal defects
    SYMPTOMS

 and

    subsarcolemmal lesions indistinguishable from those in Duchenne muscular dystrophy
    SYMPTOMS

. Both disorders share certain ultrastructure features that suggest a common pathogenesis related to

    primary deficiency of transmembrane glycoproteins (e.g., sarcoglycans)
    BIOCHEMICAL

 or

    deficiency in dystrophin
    BIOCHEMICAL

, which produces a

    secondary deficiency in sarcoglycans
    BIOCHEMICAL

. The

    lack of transmembrane glycoproteins
    BIOCHEMICAL

 may contribute to

    membrane lesions
    MICROSCOPIC

 and associated

    muscle fiber degeneration and necrosis
    SYMPTOMS

.


The concomitant use of dystrophin and utrophin/dystrophin related protein antibodies to reduce misdiagnosis of Duchenne/Becker muscular dystrophy.

Antibodies to dystrophin have increased accuracy in the diagnosis of Duchenne/Becker muscular dystrophy (D/BMD). Both typical and 'atypical' presentations of this disease can be confirmed by demonstrating qualitative and quantitative defects in the expression of dystrophin protein. However, owing to the propensity for dystrophin degradation in vitro, caution needs to be applied while performing and interpreting antibody-based dystrophin analysis. Here we identify two cases where in vitro protein degradation caused diagnostic confusion. We demonstrate the use of utrophin/dystrophin related protein (DRP) as sensitive control for sample degradation, since it is more labile than dystrophin. We suggest that the concomitant or sequential usage of antibodies specific for dystrophin along with utrophin/DRP can help reduce the misdiagnosis of D/BMD.

    Antibodies to dystrophin
    BIOCHEMICAL

 have increased accuracy in the diagnosis of

    Duchenne/Becker muscular dystrophy (D/BMD)
    DIAGNOSIS

. Both typical and 'atypical' presentations of this disease can be confirmed by demonstrating

    qualitative and quantitative defects in the expression of dystrophin protein
    BIOCHEMICAL

. However, owing to the propensity for

    dystrophin degradation
    BIOCHEMICAL

 in vitro, caution needs to be applied while performing and interpreting

    antibody-based dystrophin analysis
    PARACLINICAL

. Here we identify two cases where

    in vitro protein degradation
    MICROSCOPIC

 caused diagnostic confusion. We demonstrate the use of

    utrophin/dystrophin related protein (DRP
    BIOCHEMICAL

) as sensitive control for sample degradation, since it is more labile than dystrophin. We suggest that the concomitant or sequential usage of antibodies specific for dystrophin along with utrophin/DRP can help reduce the misdiagnosis of

    D/BMD
    DIAGNOSIS

.


[A case of pacemaker implantation for complete atrioventricular block associated with Duchenne muscular dystrophy].

We report here a case of Duchenne muscular dystrophy (DMD) who underwent pacemaker implantation for complete atrioventricular block. This 30 year-old male had the deletion of exon 45-52 in the dystrophin gene and complained of palpitation and precordial oppression. Because his electrocardiogram showed complete atrioventricular block, a permanent pacemaker was implanted. He has been doing well for 15 months after implantation. There have been few reports about pacemaker implantation for patients with DMD. As these patients survive longer by mechanical ventilation with chest respirators or nasal intermittent positive pressure ventilators, an increasing number of cases may require pacemaker implantation.

We report here a case of

    Duchenne muscular dystrophy (DMD)
    DIAGNOSIS

 who underwent

    pacemaker implantation
    MEDICATION

 for

    complete atrioventricular block
    DIAGNOSIS

. This

    30 year-old
    AGE

    male
    GENDER

 had the

    deletion of exon 45-52 in the dystrophin gene
    GENETICS

 and complained of

    palpitation
    SYMPTOMS

 and

    precordial oppression
    SYMPTOMS

. Because his

    electrocardiogram
    PARACLINICAL

 showed

    complete atrioventricular block
    SYMPTOMS

, a

    permanent pacemaker was implanted
    MEDICATION

.

    He
    GENDER

 has been doing well for 15 months after implantation. There have been few reports about

    pacemaker implantation
    MEDICATION

 for patients with

    DMD
    DIAGNOSIS

. As these patients survive longer by

    mechanical ventilation with chest respirators
    MEDICATION

 or

    nasal intermittent positive pressure ventilators
    MEDICATION

, an increasing number of cases may require

    pacemaker implantation
    MEDICATION

.

Duchenne muscular dystrophy (DMD)
complete atrioventricular block
DMD

palpitation
precordial oppression
complete atrioventricular block


Deficiency of syntrophin, dystroglycan, and merosin in a female infant with a congenital muscular dystrophy phenotype lacking cysteine-rich and C-terminal domains of dystrophin.

Primary deficiency of merosin is the cause of the classic form of congenital muscular dystrophy (CMD) accompanied by brain white matter abnormalities. We report a female infant with dystrophinopathy who was deficient in merosin in skeletal muscle. The patient had a phenotype of typical CMD and white matter abnormalities on brain MRI. Merosin was greatly reduced in the biopsied skeletal muscle. However, the expression of dystroglycan and syntrophin was also greatly reduced, and the immunoreactivity for the antibodies against the cysteine-rich/C-terminal domains of dystrophin was absent in the sarcolemma. Reverse transcriptase polymerase chain reaction analysis of the dystrophin gene revealed a complete lack of exons 71 through 74. In skeletal muscle, only the mutant gene was expressed. These results suggest that the patient is a symptomatic Duchenne muscular dystrophy carrier with skewed X-inactivation. This patient illustrates for the first time that a dystrophin abnormality can cause a secondary deficiency of merosin in dystrophinopathy. The reduction of merosin may account for the clinical phenotype of CMD and correlate with the white matter abnormalities in our patient.

    Primary deficiency of merosin
    BIOCHEMICAL

 is the cause of the classic form of

    congenital muscular dystrophy (CMD)
    DIAGNOSIS

 accompanied by

    brain white matter abnormalities
    SYMPTOMS

. We report a

    female
    GENDER

    infant
    AGE

 with

    dystrophinopathy
    DIAGNOSIS

 who was

    deficient in merosin in skeletal muscle
    BIOCHEMICAL

. The patient had a phenotype of typical

    CMD
    DIAGNOSIS

 and

    white matter abnormalities
    SYMPTOMS

 on

    brain MRI
    PARACLINICAL

.

    Merosin was greatly reduced in the biopsied skeletal muscle
    MICROSCOPIC

. However, the

    expression of dystroglycan and syntrophin was also greatly reduced
    BIOCHEMICAL

, and the

    immunoreactivity for the antibodies against the cysteine-rich/C-terminal domains of dystrophin was absent in the sarcolemma
    BIOCHEMICAL

.

    Reverse transcriptase polymerase chain reaction analysis of the dystrophin gene
    PARACLINICAL

 revealed a

    complete lack of exons 71 through 74
    GENETICS

.

    In skeletal muscle
    MICROSCOPIC

,

    only the mutant gene was expressed
    GENETICS

. These results suggest that the patient is a symptomatic

    Duchenne muscular dystrophy
    DIAGNOSIS

 carrier with

    skewed X-inactivation
    GENETICS

. This patient illustrates for the first time that a

    dystrophin abnormality
    GENETICS

 can cause a

    secondary deficiency of merosin
    BIOCHEMICAL

 in

    dystrophinopathy
    DIAGNOSIS

. The

    reduction of merosin
    BIOCHEMICAL

 may account for the clinical phenotype of

    CMD
    DIAGNOSIS

 and correlate with the

    white matter abnormalities
    SYMPTOMS

 in our patient.

congenital muscular dystrophy (CMD)
dystrophinopathy
CMD
Duchenne muscular dystrophy
dystrophinopathy
CMD

brain white matter abnormalities
white matter abnormalities
white matter abnormalities

complete lack of exons 71 through 74
only the mutant gene was expressed
skewed X-inactivation
dystrophin abnormality


Xp21 muscular dystrophy due to X chromosome inversion.

Two brothers with Duchenne muscular dystrophy have an inversion of the X chromosome, 46, Y, inv(X) (p11.2p21.2). Because their mother is an unaffected carrier of the inversion, this confirms that maternal passage of a structurally abnormal X chromosome can cause dystrophinopathy in males. Our experience suggests that as well as molecular genetic analysis, karyotyping can be useful in Xp21 muscular dystrophy.

Two

    brothers
    GENDER

 with

    Duchenne muscular dystrophy
    DIAGNOSIS

 have an

    inversion of the X chromosome, 46, Y, inv(X) (p11.2p21.2)
    GENETICS

. Because

    their mother is an unaffected carrier of the inversion
    FAMILY

, this confirms that

    maternal passage of a structurally abnormal X chromosome
    GENETICS

 can cause

    dystrophinopathy
    DIAGNOSIS

 in

    males
    GENDER

. Our experience suggests that as well as

    molecular genetic analysis
    PARACLINICAL

,

    karyotyping
    PARACLINICAL

 can be useful in

    Xp21 muscular dystrophy
    DIAGNOSIS

.

Duchenne muscular dystrophy
dystrophinopathy
Xp21 muscular dystrophy


Patient with an Xp21 contiguous gene deletion syndrome in association with agenesis of the corpus callosum.

The so-called Xp21 contiguous deletion syndrome or complex glycerol kinase deficiency (GKD) usually presents with classical Duchenne muscular dystrophy (DMD) or a milder dystrophic myopathy, adrenal hypoplasia, and GKD. A number of syndromic and nonsyndromic cases of agenesis of the corpus callosum (ACC) also map to that location. To date, none of the cases of complex GKD have been associated with ACC. Here, we report on a patient with a complex phenotype as a result of the Xp21 contiguous deletion syndrome in association with ACC. Biochemical, cytogenetic, and molecular analyses were performed to detect and establish the size of the genomic deletion. It is at least 3 million base pairs in length; however, exact limits could not be determined in the present study. Nevertheless, we suggest the presence of a primary gene involved in the embryogenesis of the corpus callosum between Xp21.1 and Xp22.11.

The so-called

    Xp21 contiguous deletion syndrome
    DIAGNOSIS

 or

    complex glycerol kinase deficiency (GKD)
    DIAGNOSIS

 usually presents with

    classical Duchenne muscular dystrophy (DMD)
    DIAGNOSIS

 or a

    milder dystrophic myopathy
    DIAGNOSIS

,

    adrenal hypoplasia
    SYMPTOMS

, and

    GKD
    DIAGNOSIS

. A number of syndromic and

    nonsyndromic
    DIAGNOSIS

 cases of

    agenesis of the corpus callosum (ACC)
    SYMPTOMS

 also map to that location. To date, none of the cases of

    complex GKD
    DIAGNOSIS

 have been associated with

    ACC
    DIAGNOSIS

. Here, we report on a patient with a complex phenotype as a result of the

    Xp21 contiguous deletion syndrome
    DIAGNOSIS

 in association with

    ACC
    SYMPTOMS

.

    Biochemical, cytogenetic, and molecular analyses
    PARACLINICAL

 were performed to detect and establish the size of

    the genomic deletion. It is at least 3 million base pairs in length
    GENETICS

; however, exact limits could not be determined in the present study. Nevertheless, we suggest the presence of a primary gene involved in the embryogenesis of the corpus callosum between Xp21.1 and Xp22.11.

adrenal hypoplasia
agenesis of the corpus callosum (ACC)
ACC


Recent advances in diagnosis of the childhood muscular dystrophies.

Recent advances in molecular genetics research have revolutionised our understanding of the childhood muscular dystrophies. The first breakthrough came in 1987 with the identification of the gene for dystrophin, the protein that is abnormal in X-linked Duchenne muscular dystrophy. Dystrophin is bound to a complex of proteins in the muscle membrane, and primary abnormalities of these proteins have now been identified as the cause of some autosomally inherited forms of muscular dystrophy. A group of transmembrane proteins known as alpha- (adhalin) beta-, gamma- and delta-sarcoglycan are deficient in autosomal recessive limb-girdle muscular dystrophy, and the extracellular matrix protein merosin (alpha2-laminin), is deficient in a subset of patients with congenital muscular dystrophy. Identification of primary deficiencies in these 'dystrophin associated proteins' will result in improved diagnostic accuracy, more accurate genetic counselling and, in some cases, the availability of prenatal diagnosis.

Recent advances in molecular genetics research have revolutionised our understanding of the

    childhood muscular dystrophies
    DIAGNOSIS

. The first breakthrough came in 1987 with the identification of the

    gene for dystrophin
    GENETICS

, the

    protein that is abnormal
    GENETICS

 in

    X-linked
    GENETICS

    Duchenne muscular dystrophy
    DIAGNOSIS

. Dystrophin is bound to a

    complex of proteins in the muscle membrane
    MICROSCOPIC

, and

    primary abnormalities of these proteins
    GENETICS

 have now been identified as the cause of some

    autosomally inherited
    GENETICS

 forms of

    muscular dystrophy
    DIAGNOSIS

. A group of transmembrane proteins known as

    alpha- (adhalin) beta-, gamma- and delta-sarcoglycan are deficient
    BIOCHEMICAL

 in

    autosomal recessive limb-girdle muscular dystrophy
    DIAGNOSIS

, and the

    extracellular matrix protein merosin (alpha2-laminin)
    BIOCHEMICAL

, is

    deficient
    BIOCHEMICAL

 in a subset of patients with

    congenital muscular dystrophy
    DIAGNOSIS

. Identification of primary deficiencies in these 'dystrophin associated proteins' will result in improved diagnostic accuracy, more accurate

    genetic counselling
    MEDICATION

 and, in some cases, the availability of

    prenatal diagnosis
    MEDICATION

.

gene for dystrophin
protein that is abnormal
X-linked
primary abnormalities of these proteins
autosomally inherited


Noninvasive ventilation during percutaneous gastrostomy placement in Duchenne muscular dystrophy.

Noninvasive positive pressure ventilation (NPPV) is used for respiratory support in a number of diseases causing acute or chronic respiratory failure. We describe a novel use of NPPV to provide respiratory support during sedation for percutaneous placement of a gastrostomy tube in a patient with Duchenne muscular dystrophy (DMD). The patient had severe respiratory insufficiency, progressive dysphagia, and undernutrition. In addition to the case in this report, we have used NPPV to provide respiratory support to DMD patients during five other gastrointestinal endoscopies without complication. The technique is highly labor intensive and requires physicians and respiratory therapists familiar with NPPV. The primary risk associated with this technique is lack of definitive airway protection during the procedure, which must be balanced against the risks of intubation in an anesthetized patient with neuromuscular disease. The potential benefit to selected patients is substantial, such as initiation of gastrostomy tube feeding in our patient, with subsequent improvement in his quality of life and nutritional status.

    Noninvasive positive pressure ventilation (NPPV)
    MEDICATION

 is used for

    respiratory support
    MEDICATION

 in a number of diseases causing

    acute or chronic respiratory failure
    SYMPTOMS

. We describe a

    novel use of NPPV to provide respiratory support
    MEDICATION

 during

    sedation
    MEDICATION

 for

    percutaneous placement of a gastrostomy tube
    MEDICATION

 in a patient with

    Duchenne muscular dystrophy (DMD)
    DIAGNOSIS

. The patient had

    severe respiratory insufficiency
    SYMPTOMS

,

    progressive dysphagia
    SYMPTOMS

, and

    undernutrition
    SYMPTOMS

. In addition to the case in this report, we have used

    NPPV to provide respiratory support
    MEDICATION

 to

    DMD
    DIAGNOSIS

 patients during five other

    gastrointestinal endoscopies
    MEDICATION

    without complication
    NEG_FINDINGS

. The technique is highly labor intensive and requires physicians and

    respiratory therapists
    PARACLINICAL

 familiar with

    NPPV
    MEDICATION

. The primary risk associated with this technique is

    lack of definitive airway protection
    NEG_FINDINGS

 during the procedure, which must be balanced against the risks of

    intubation
    MEDICATION

 in an anesthetized patient with

    neuromuscular disease
    DIAGNOSIS

. The potential benefit to selected patients is substantial, such as

    initiation of gastrostomy tube feeding
    MEDICATION

 in our patient, with subsequent improvement in his

    quality of life and nutritional status
    SYMPTOMS

.

acute or chronic respiratory failure
severe respiratory insufficiency
progressive dysphagia
undernutrition
quality of life and nutritional status

Duchenne muscular dystrophy (DMD)
DMD
neuromuscular disease

without complication
lack of definitive airway protection


A small intraexonic deletion within the dystrophin gene suggests a possible mechanism of mutagenesis.

A case of Duchenne muscular dystrophy is described with an unusual mutation consisting of a 17-bp deletion within exon 47 of the dystrophin gene. The sequences on either side of the deletion have a high degree of intrastrand base complementarity. It is hypothesised that the mechanism generating the deletion may have been the formation of hairpin loop structure in a single strand of DNA followed by enzymatic degradation at unpaired regions within the loop.

A case of

    Duchenne muscular dystrophy
    DIAGNOSIS

 is described with an

    unusual mutation consisting of a 17-bp deletion within exon 47 of the dystrophin gene
    GENETICS

.

    The sequences on either side of the deletion have a high degree of intrastrand base complementarity
    GENETICS

. It is hypothesised that the mechanism generating the deletion may have been the

    formation of hairpin loop structure in a single strand of DNA
    GENETICS

 followed by

    enzymatic degradation at unpaired regions within the loop
    GENETICS

.


Muscle pathology and clinical features of the sarcolemmopathies.

We report the clinical features and the muscle pathology in 2 patients with congenital muscular dystrophy (CMD) secondary to merosin deficiency and in 2 patients with sarcoglycan (adhalin) deficiency. Electron microscopic examination revealed sarcolemmal defects in non-necrotic muscle fibers in all cases. These pathological findings are indistinguishable from those of Duchenne/Becker muscular dystrophy. We suggest that the similarities in histological findings reflect a common pathogenetic mechanism, i.e., a structural weakening of the sarcolemma with an increased susceptibility to rupture under mechanical stress. We propose the term sarcolemmopathy as an all-encompassing rubric for these disorders.

We report the clinical features and the

    muscle pathology
    PARACLINICAL

 in 2 patients with

    congenital muscular dystrophy (CMD)
    DIAGNOSIS

 secondary to

    merosin deficiency
    BIOCHEMICAL

 and in 2 patients with

    sarcoglycan (adhalin) deficiency
    BIOCHEMICAL

.

    Electron microscopic examination
    PARACLINICAL

 revealed

    sarcolemmal defects in non-necrotic muscle fibers
    MICROSCOPIC

 in all cases. These pathological findings are indistinguishable from those of

    Duchenne/Becker muscular dystrophy
    DIAGNOSIS

. We suggest that the

    similarities in histological findings
    SYMPTOMS

 reflect a common pathogenetic mechanism, i.e., a

    structural weakening of the sarcolemma with an increased susceptibility to rupture under mechanical stress
    SYMPTOMS

. We propose the term

    sarcolemmopathy
    DIAGNOSIS

 as an all-encompassing rubric for these disorders.

congenital muscular dystrophy (CMD)
Duchenne/Becker muscular dystrophy
sarcolemmopathy

merosin deficiency
sarcoglycan (adhalin) deficiency


Uniparental disomy of the entire X chromosome in a female with Duchenne muscular dystrophy.

Duchenne muscular dystrophy (DMD) is a severe, progressive, X-linked muscle-wasting disorder with an incidence of approximately 1/3,500 male births. Females are also affected, in rare instances. The manifestation of mild to severe symptoms in female carriers of dystrophin mutations is often the result of the preferential inactivation of the X chromosome carrying the normal dystrophin gene. The severity of the symptoms is dependent on the proportion of cells that have inactivated the normal X chromosome. A skewed pattern of X inactivation is also responsible for the clinical manifestation of DMD in females carrying X;autosome translocations, which disrupt the dystrophin gene. DMD may also be observed in females with Turner syndrome (45,X), if the remaining X chromosome carries a DMD mutation. We report here the case of a karyotypically normal female affected with DMD as a result of homozygosity for a deletion of exon 50 of the dystrophin gene. PCR analysis of microsatellite markers spanning the length of the X chromosome demonstrated that homozygosity for the dystrophin gene mutation was caused by maternal isodisomy for the entire X chromosome. This finding demonstrates that uniparental isodisomy of the X chromosome is an additional mechanism for the expression of X-linked recessive disorders. The proband's clinical presentation is consistent with the absence of imprinted genes (i.e., genes that are selectively expressed based on the parent of origin) on the X chromosome.

    Duchenne muscular dystrophy (DMD)
    DIAGNOSIS

 is a

    severe, progressive, X-linked
    DIAGNOSIS

    muscle-wasting disorder
    DIAGNOSIS

 with an incidence of approximately 1/3,500

    male
    GENDER

 births.

    Females
    GENDER

 are also affected, in rare instances. The manifestation of

    mild to severe symptoms
    SYMPTOMS

 in

    female
    GENDER

 carriers of

    dystrophin mutations
    GENETICS

 is often the result of the

    preferential inactivation of the X chromosome carrying the normal dystrophin gene
    GENETICS

. The severity of the symptoms is dependent on the proportion of cells that have

    inactivated the normal X chromosome
    GENETICS

. A

    skewed pattern of X inactivation
    GENETICS

 is also responsible for the clinical manifestation of

    DMD
    DIAGNOSIS

 in

    females
    GENDER

 carrying

    X;autosome translocations, which disrupt the dystrophin gene
    GENETICS

.

    DMD
    DIAGNOSIS

 may also be observed in

    females
    GENDER

 with

    Turner syndrome (45,X)
    DIAGNOSIS

, if

    the remaining X chromosome carries a DMD mutation
    GENETICS

. We report here the case of a

    karyotypically normal
    NEG_FINDINGS

    female
    GENDER

 affected with

    DMD
    DIAGNOSIS

 as a result of

    homozygosity for a deletion of exon 50 of the dystrophin gene
    GENETICS

.

    PCR analysis of microsatellite markers spanning the length of the X chromosome
    PARACLINICAL

 demonstrated that

    homozygosity for the dystrophin gene mutation was caused by maternal isodisomy for the entire X chromosome
    GENETICS

. This finding demonstrates that

    uniparental isodisomy of the X chromosome
    GENETICS

 is an additional mechanism for the expression of

    X-linked recessive disorders
    GENETICS

. The proband's clinical presentation is consistent with the

    absence of imprinted genes (i.e., genes that are selectively expressed based on the parent of origin) on the X chromosome
    GENETICS

.

Duchenne muscular dystrophy (DMD)
severe, progressive, X-linked
muscle-wasting disorder
DMD
DMD
Turner syndrome (45,X)
DMD


Clinical and molecular analysis of a large family with three distinct phenotypes of progressive muscular dystrophy.

We describe a unique six-generation, highly consanguineous family originating from an isolated mountainous village in the Russian province of Daghestan. Three separate clinical phenotypes of progressive muscular dystrophy were identified in this large family. Seven patients developed a classical limb-girdle variant of muscular dystrophy (LGMD), with disease onset at 15-30 years and loss of ambulation within a 25-year course. The second group included three patients with a slowly progressive distal myopathy first manifested in the late teens and confined to the tibial and calf muscles. Each of these two phenotypes segregated independently as an autosomal recessive trait, and muscle biopsies showed non-specific myopathic changes. Lastly, two male siblings exhibited an atypical variant of Duchenne muscular dystrophy confirmed by detection of a deletion in the dystrophin gene. To clarify the molecular basis of the polymorphic autosomal recessive form of muscular dystrophy in this kindred, we performed molecular genetic studies on 67 family members and obtained significant evidence for linkage to chromosome 2p. A maximum pairwise lod (logarithm of odds) score of 5.64 was achieved at the zero recombination fraction (i.e. at theta = 0.00) for locus D2S291; multipoint linkage analysis confirmed the most likely location of a mutant gene near D2S291. The patients with LGMD and those with the distal muscular dystrophy phenotype share a common affected homozygous haplotype associated with the same founder chromosome; key recombinants defined D2S286 and D2S292 to be the closest loci flanking the mutant gene. Remarkably, two clinically distinct forms of autosomal recessive muscular dystrophy, LGMD type 2B (LGMD2B) and Miyoshi myopathy, were recently mapped to the same locus. We suggest that all three chromosome 2p-linked conditions may represent allelic disorders, i.e. different phenotypic expressions of a single gene.

We describe a unique

    six-generation, highly consanguineous family
    FAMILY

 originating from an

    isolated mountainous village
    ETHNICITY

 in the

    Russian province
    ETHNICITY

 of

    Daghestan
    ETHNICITY

. Three separate clinical phenotypes of

    progressive muscular dystrophy
    DIAGNOSIS

 were identified in this large family. Seven patients developed a

    classical limb-girdle variant of muscular dystrophy (LGMD)
    DIAGNOSIS

, with disease onset

    at 15-30 years
    AGE

 and

    loss of ambulation within a 25-year course
    SYMPTOMS

. The second group included three patients with a

    slowly progressive distal myopathy
    DIAGNOSIS

 first manifested

    in the late teens
    AGE

 and

    confined to the tibial and calf muscles
    SYMPTOMS

. Each of these two phenotypes segregated independently

    as an autosomal recessive trait
    GENETICS

, and

    muscle biopsies
    PARACLINICAL

 showed

    non-specific myopathic changes
    NEG_FINDINGS

. Lastly, two

    male
    GENDER

    siblings exhibited an atypical variant of Duchenne muscular dystrophy
    FAMILY

 confirmed by detection of a

    deletion in the dystrophin gene
    GENETICS

. To clarify the molecular basis of the

    polymorphic autosomal recessive form of muscular dystrophy
    DIAGNOSIS

 in this kindred, we performed

    molecular genetic studies
    PARACLINICAL

 on

    67 family members
    PARACLINICAL

 and obtained significant evidence for

    linkage to chromosome 2p
    GENETICS

. A maximum pairwise lod (logarithm of odds) score of 5.64 was achieved at the zero recombination fraction (i.e. at theta = 0.00) for

    locus D2S291
    GENETICS

;

    multipoint linkage analysis
    PARACLINICAL

 confirmed the most likely location of a

    mutant gene near D2S291
    GENETICS

. The patients with

    LGMD
    DIAGNOSIS

 and those with the

    distal muscular dystrophy
    DIAGNOSIS

 phenotype

    share a common affected homozygous haplotype associated with the same founder chromosome
    FAMILY

;

    key recombinants
    PARACLINICAL

 defined

    D2S286 and D2S292
    GENETICS

 to be the

    closest loci flanking the mutant gene
    GENETICS

. Remarkably, two clinically distinct forms of

    autosomal recessive muscular dystrophy
    DIAGNOSIS

,

    LGMD type 2B (LGMD2B)
    DIAGNOSIS

 and

    Miyoshi myopathy
    DIAGNOSIS

, were recently mapped to the same locus. We suggest that all three

    chromosome 2p-linked
    GENETICS

 conditions may represent

    allelic disorders
    GENETICS

, i.e. different phenotypic expressions of a single gene.

isolated mountainous village
Russian province
Daghestan

as an autosomal recessive trait
deletion in the dystrophin gene
linkage to chromosome 2p
locus D2S291
mutant gene near D2S291
D2S286 and D2S292
closest loci flanking the mutant gene
chromosome 2p-linked
allelic disorders


HyperCKemic, proximal muscular dystrophies and the dystrophin membrane cytoskeleton, including dystrophinopathies, sarcoglycanopathies, and merosinopathies.

Of the various muscular dystrophies, the dystrophinopathies are the most common, accounting for the majority of male muscle disease patients and for about 10% of female patients referred for the evaluation of muscular dystrophy or persistent high serum creatine kinase values (hyperCKemia). The approach to diagnosis and family genetic counseling for the dystrophinopathies is now well established, and implementation of carrier detection and prenatal diagnosis has dramatically decreased the incidence of familial cases. With the decreasing observation of a positive family history in newly ascertained cases, molecular genetic and protein studies become imperative for accurate diagnosis. Genetic counseling in families of isolated cases can still be problematic. There is a wide range of opinions regarding the management of Duchenne muscular dystrophy, with surgical interventions (eg, tendon lengthenings and spinal fusion), steroid use, and extent of respiratory support actively debated. There has been progress in defining the underlying cause of disease for some patients of muscular dystrophy who have normal dystrophin findings. Nearly all patients with proximal, hyperCKemic muscular dystrophy who have normal dystrophin show no family history of the disorder, consistent with autosomal recessive disease. Approximately 5% of both boys and girls with childhood-onset dystrophy and normal dystrophin have been found to have mutations in one of the four sarcoglycan proteins identified to date. Also, approximately half of the patients with congenital muscular dystrophy show deficiency of a component of the muscular extracellular matrix. (merosin/laminin-alpha 2). In this review, we give a short primer on relevant muscle structure and function, followed by a series of case reports on patients referred for molecular testing that illustrate the diagnostic protocols, range of clinical presentations, and genetic counseling options in the work-up of proximal muscular dystrophy and hyperCKemia.

Of the various

    muscular dystrophies
    DIAGNOSIS

, the

    dystrophinopathies
    DIAGNOSIS

 are the most common, accounting for the majority of

    male
    GENDER

    muscle disease
    DIAGNOSIS

 patients and for about 10% of

    female
    GENDER

 patients referred for the evaluation of

    muscular dystrophy
    DIAGNOSIS

 or

    persistent high serum creatine kinase values
    BIOCHEMICAL

 (

    hyperCKemia)
    BIOCHEMICAL

. The approach to diagnosis and

    family genetic counseling
    MEDICATION

 for the

    dystrophinopathies
    DIAGNOSIS

 is now well established, and implementation of carrier detection and

    prenatal diagnosis
    MEDICATION

 has dramatically decreased the incidence of familial cases. With the decreasing observation of a

    positive family history
    FAMILY

 in newly ascertained cases,

    molecular genetic and protein studies
    PARACLINICAL

 become imperative for accurate diagnosis.

    Genetic counseling
    MEDICATION

 in families of isolated cases can still be problematic. There is a wide range of opinions regarding the management of

    Duchenne muscular dystrophy
    DIAGNOSIS

, with

    surgical interventions (eg, tendon lengthenings and spinal fusion)
    MEDICATION

,

    steroid use
    MEDICATION

, and

    extent of respiratory support
    MEDICATION

 actively debated. There has been progress in defining the underlying cause of disease for some patients of

    muscular dystrophy
    DIAGNOSIS

 who have

    normal dystrophin findings
    NEG_FINDINGS

. Nearly all patients with

    proximal, hyperCKemic muscular dystrophy
    DIAGNOSIS

 who have

    normal dystrophin
    NEG_FINDINGS

 show

    no family history of the disorder
    NEG_FINDINGS

, consistent with

    autosomal recessive disease
    GENETICS

. Approximately 5% of both

    boys
    GENDER

 and

    girls
    GENDER

 with

    childhood-onset dystrophy
    DIAGNOSIS

 and

    normal dystrophin
    NEG_FINDINGS

 have been found to have

    mutations in one of the four sarcoglycan proteins
    GENETICS

 identified to date. Also, approximately half of the patients with

    congenital muscular dystrophy
    DIAGNOSIS

 show

    deficiency of a component of the muscular extracellular matrix. (merosin/laminin-alpha 2)
    BIOCHEMICAL

. In this review, we give a short primer on relevant muscle structure and function, followed by a series of case reports on patients referred for

    molecular testing
    PARACLINICAL

 that illustrate the diagnostic protocols, range of clinical presentations, and genetic counseling options in the

    work-up
    PARACLINICAL

 of

    proximal muscular dystrophy
    DIAGNOSIS

 and

    hyperCKemia
    DIAGNOSIS

.

normal dystrophin findings
normal dystrophin
no family history of the disorder
normal dystrophin


Duchenne phenotype with in-frame deletion removing major portion of dystrophin rod: threshold effect for deletion size?

In a 9-year-old boy with Duchenne muscular dystrophy we found a large in-frame deletion, spanning exons 10 to 53 of the dystrophin gene. The deletion removed almost all of the central rod domain of dystrophin. Using carboxyterminal dystrophin antibodies the immunohistochemical reaction was normal in all muscle fibers. In immunoblot studies we found dystrophin of abnormal size (160 kDa) and normal amount (about 100%). The immunochemical features and the reading frame deduced from DNA analysis are usually associated with Becker muscular dystrophy, but the clinical characteristics were those of the severe Duchenne phenotype. All the cases of in-frame dystrophin deletions reported so far, which involved more than 36 exons, invariably resulted in a severe phenotype. Therefore, a threshold effect for dystrophin length may be reasonably suspected. Very short dystrophin molecules might induce a severe disarray of the dystrophin network.

In a

    9-year-old
    AGE

    boy
    GENDER

 with

    Duchenne muscular dystrophy
    DIAGNOSIS

 we found a

    large in-frame deletion, spanning exons 10 to 53 of the dystrophin gene
    GENETICS

. The

    deletion removed almost all of the central rod domain of dystrophin
    GENETICS

. Using

    carboxyterminal dystrophin antibodies
    NEG_FINDINGS

 the

    immunohistochemical reaction was normal in all muscle fibers
    NEG_FINDINGS

. In

    immunoblot studies
    PARACLINICAL

 we found

    dystrophin of abnormal size (160 kDa) and normal amount (about 100%)
    BIOCHEMICAL

. The immunochemical features and the reading frame deduced from

    DNA analysis
    PARACLINICAL

 are usually associated with

    Becker muscular dystrophy
    DIAGNOSIS

, but the clinical characteristics were those of the

    severe Duchenne
    DIAGNOSIS

 phenotype. All the cases of

    in-frame dystrophin deletions
    GENETICS

 reported so far, which involved

    more than 36 exons
    GENETICS

, invariably resulted in a

    severe phenotype
    SYMPTOMS

. Therefore, a threshold effect for dystrophin length may be reasonably suspected.

    Very short dystrophin molecules
    BIOCHEMICAL

 might induce a

    severe disarray of the dystrophin network
    SYMPTOMS

.

Duchenne muscular dystrophy
Becker muscular dystrophy
severe Duchenne


Duchenne muscular dystrophy in a female patient : a case report.

A female patient with Duchenne muscular dystrophy (DMD) with no prior family history of DMD is described. She presented with proximal muscle weakness, enlarged calf muscles and an elevated serum creatine kinase (CK). Histological examination of skeletal muscle revealed myopathic changes and immunoperoxidase examination for dystrophin in muscle biopsy demonstrated a mosaic pattern. Immunostaining of a muscle biopsy with anti-dystrophic serum proved to be valuable in the diagnosis of DMD in a symptomatic female carrier.

A

    female
    GENDER

 patient with

    Duchenne muscular dystrophy (DMD)
    DIAGNOSIS

 with

    no prior family history of DMD
    NEG_FINDINGS

 is described.

    She
    GENDER

 presented with

    proximal muscle weakness
    SYMPTOMS

,

    enlarged calf muscles
    SYMPTOMS

 and an

    elevated serum creatine kinase (CK)
    BIOCHEMICAL

.

    Histological examination of skeletal muscle
    PARACLINICAL

 revealed

    myopathic changes
    MICROSCOPIC

 and

    immunoperoxidase examination for dystrophin in muscle biopsy
    PARACLINICAL

 demonstrated a

    mosaic pattern
    MICROSCOPIC

.

    Immunostaining of a muscle biopsy with anti-dystrophic serum
    PARACLINICAL

 proved to be valuable in the diagnosis of

    DMD
    DIAGNOSIS

 in a symptomatic

    female
    GENDER

 carrier.

proximal muscle weakness
enlarged calf muscles


[Dystrophin abnormality in a patient with polymyositis associated with primary biliary cirrhosis and myocardial injury].

We have reported a 58-year-old Japanese female with polymyositis, primary biliary cirrhosis (PBC) and arrhythmia. In contrast to the previously reported 13 cases of polymyositis associated with PBC, symptoms and laboratory data abnormalities responded to oral administration of predonisolone. Interestingly, immunohistochemical and immunoblot analyses of biopsied skeletal muscle revealed diminished expression of dystrophin carboxyl-terminal domain in the sarcolemma, suggesting that, in analogy to Duchenne muscular dystrophy, secondary abnormality of the link between the basal lamina and cytoskeleton via the dystrophinglycoprotein complex may have played a role in the molecular pathogenesis of muscle fiber degeneration in this patient.

We have reported a

    58-year-old
    AGE

    Japanese
    ETHNICITY

    female
    GENDER

 with

    polymyositis
    DIAGNOSIS

,

    primary biliary cirrhosis (PBC)
    DIAGNOSIS

 and

    arrhythmia
    SYMPTOMS

. In contrast to the previously reported 13 cases of

    polymyositis
    DIAGNOSIS

 associated with

    PBC
    DIAGNOSIS

, symptoms and

    laboratory data abnormalities
    SYMPTOMS

 responded to

    oral administration of predonisolone
    MEDICATION

. Interestingly,

    immunohistochemical and immunoblot analyses of biopsied skeletal muscle
    PARACLINICAL

 revealed

    diminished expression of dystrophin carboxyl-terminal domain in the sarcolemma
    MICROSCOPIC

, suggesting that, in analogy to

    Duchenne muscular dystrophy
    DIAGNOSIS

,

    secondary abnormality of the link between the basal lamina and cytoskeleton via the dystrophinglycoprotein complex
    SYMPTOMS

 may have played a role in the molecular pathogenesis of

    muscle fiber degeneration
    SYMPTOMS

 in this patient.

polymyositis
primary biliary cirrhosis (PBC)
polymyositis
PBC
Duchenne muscular dystrophy


A case of Becker muscular dystrophy resulting from the skipping of four contiguous exons (71-74) of the dystrophin gene during mRNA maturation.

The mutations in one-third of both Duchenne and Becker muscular dystrophy patients remain unknown because they do not involve gross rearrangements of the dystrophin gene. Here we report the first example of multiple exon skipping during the splicing of dystrophin mRNA precursor encoded by an apparently normal dystrophin gene. A 9-year-old Japanese boy exhibiting excessive fatigue and high serum creatine kinase activity was examined for dystrophinopathy. An immunohistochemical study of muscle tissue biopsy disclosed faint and discontinuous staining of the N-terminal and rod domains of dystrophin but no staining at all of the C-terminal domain of dystrophin. The dystrophin transcript from muscle tissue was analyzed by the reverse transcriptase polymerase chain reaction. An amplified product encompassing exons 67-79 of dystrophin cDNA was found to be smaller than that of the wild-type product. Sequence analysis of this fragment showed that the 3' end of exon 70 was directly connected to the 5' end of exon 75 and, thus, that exons 71-74 were completely absent. As a result, a truncated dystrophin protein lacking 110 amino acids from the C-terminal domain should result from translation of this truncated mRNA, and the patient was diagnosed as having Becker muscular dystrophy at the molecular level. Genomic DNA was analyzed to identify the cause of the disappearance of these exons. Every exon-encompassing region could be amplified from genomic DNA, indicating that the dystrophin gene is intact. Furthermore, sequencing of these amplified products did not disclose any particular nucleotide change that could be responsible for the multiple exon skipping observed. Considering that exons 71-74 are spliced out alternatively in some tissue-specific isoforms, to suppose that the alternative splicing machinery is present in the muscle tissue of the index case and that it is activated by an undetermined mechanism is reasonable. These results illustrate a novel genetic anomaly that results in dystrophinopathy.

The mutations in one-third of both

    Duchenne
    DIAGNOSIS

 and

    Becker muscular dystrophy
    DIAGNOSIS

 patients remain unknown because they do not involve

    gross rearrangements of the dystrophin gene
    NEG_FINDINGS

. Here we report the first example of

    multiple exon skipping during the splicing of dystrophin mRNA precursor
    GENETICS

 encoded by an

    apparently normal dystrophin gene
    GENETICS

. A

    9-year-old
    AGE

    Japanese
    ETHNICITY

    boy
    GENDER

 exhibiting

    excessive fatigue
    SYMPTOMS

 and

    high serum creatine kinase activity
    BIOCHEMICAL

 was examined for

    dystrophinopathy
    DIAGNOSIS

. An

    immunohistochemical study of muscle tissue biopsy
    PARACLINICAL

 disclosed

    faint and discontinuous staining of the N-terminal and rod domains of dystrophin
    SYMPTOMS

 but

    no staining at all of the C-terminal domain of dystrophin
    NEG_FINDINGS

.

    The dystrophin transcript from muscle tissue
    PARACLINICAL

 was

    analyzed by the reverse transcriptase polymerase chain reaction
    PARACLINICAL

. An

    amplified product encompassing exons 67-79 of dystrophin cDNA
    GENETICS

 was found

    to be smaller than that of the wild-type product
    GENETICS

.

    Sequence analysis of this fragment
    PARACLINICAL

 showed that

    the 3' end of exon 70 was directly connected to the 5' end of exon 75 and
    GENETICS

, thus,

    that exons 71-74 were completely absent
    GENETICS

. As a result, a

    truncated dystrophin protein lacking 110 amino acids from the C-terminal domain
    GENETICS

 should result from translation of this truncated mRNA, and the patient was diagnosed as having

    Becker muscular dystrophy
    DIAGNOSIS

 at the molecular level.

    Genomic DNA was analyzed
    PARACLINICAL

 to identify the cause of the

    disappearance of these exons
    GENETICS

.

    Every exon-encompassing region could be amplified from genomic DNA
    GENETICS

, indicating that the

    dystrophin gene is intact
    NEG_FINDINGS

. Furthermore,

    sequencing of these amplified products
    PARACLINICAL

 did

    not disclose any particular nucleotide change that could be responsible for the multiple exon skipping observed
    NEG_FINDINGS

. Considering that

    exons 71-74 are spliced out alternatively in some tissue-specific isoforms
    GENETICS

, to suppose that the alternative splicing machinery is present in the muscle tissue of the index case and that it is activated by an undetermined mechanism is reasonable. These results illustrate a

    novel genetic anomaly
    GENETICS

 that results in

    dystrophinopathy
    DIAGNOSIS

.

Duchenne
Becker muscular dystrophy
dystrophinopathy
Becker muscular dystrophy
dystrophinopathy


Genetic counseling of isolated carriers of Duchenne muscular dystrophy.

It has recently become possible to detect female carriers of Duchenne muscular dystrophy with no affected male relative in the family. These "isolated carriers" represent about 10% of women with high serum creatine phosphokinase (CPK) levels and clinical evidence of a muscle disease. Most isolated carriers ascertained by clinical and/or CPK levels and diagnosed by dystrophin immunostaining of muscle biopsy show symptoms of a muscular dystrophy, and often carry the diagnosis of recessive "limb-girdle muscular dystrophy" prior to dystrophin analysis. It has been difficult to offer genetic counseling and prenatal diagnosis for Duchenne muscular dystrophy in the families of these isolated carriers, largely due to the difficulty in determining which of the dystrophin alleles segregating in the family harbors the mutation in the heterozygote. Here we report genetic counseling of three isolated carriers and their families. In two cases, prenatal diagnosis of at-risk pregnancies was conducted. We determined X inactivation patterns and inheritance of X chromosomes in each family, and used this information to define the at-risk dystrophin gene. In all three families, the mutation was a de novo event, two in the paternal germ-line, and one in the maternal germ-line. In each case we show that sibs of the heterozygous woman are at population risk, while pregnancies of each propositus are at high risk. Our results show that accurate genetic counseling and prenatal diagnosis can be offered to these families.

It has recently become possible to detect

    female
    GENDER

 carriers of

    Duchenne muscular dystrophy
    DIAGNOSIS

 with

    no affected male relative in the family
    FAMILY

. These "isolated carriers" represent about 10% of

    women
    GENDER

 with

    high serum creatine phosphokinase (CPK) levels
    BIOCHEMICAL

 and

    clinical evidence of a muscle disease
    SYMPTOMS

. Most isolated carriers ascertained by clinical and/or

    CPK levels
    PARACLINICAL

 and diagnosed by

    dystrophin immunostaining of muscle biopsy
    PARACLINICAL

 show

    symptoms of a muscular dystrophy
    SYMPTOMS

, and often carry the diagnosis of

    recessive "limb-girdle muscular dystrophy"
    DIAGNOSIS

 prior to

    dystrophin analysis
    PARACLINICAL

. It has been difficult to offer

    genetic counseling
    MEDICATION

 and

    prenatal diagnosis
    MEDICATION

 for

    Duchenne muscular dystrophy
    DIAGNOSIS

 in the families of these isolated carriers, largely due to the difficulty in determining

    which of the dystrophin alleles segregating in the family harbors the mutation in the heterozygote
    GENETICS

. Here we report

    genetic counseling
    MEDICATION

 of three isolated carriers and their families. In two cases,

    prenatal diagnosis of at-risk pregnancies
    PARACLINICAL

 was conducted. We determined

    X inactivation patterns and inheritance of X chromosomes
    GENETICS

 in each family, and used this information to define the

    at-risk dystrophin gene
    GENETICS

. In all three families,

    the mutation was a de novo event, two in the paternal germ-line, and one in the maternal germ-line
    GENETICS

. In each case we show that

    sibs of the heterozygous woman are at population risk
    FAMILY

, while

    pregnancies of each propositus are at high risk
    FAMILY

. Our results show that

    accurate genetic counseling
    MEDICATION

 and

    prenatal diagnosis
    MEDICATION

 can be offered to these families.

clinical evidence of a muscle disease
symptoms of a muscular dystrophy

genetic counseling
prenatal diagnosis
genetic counseling
accurate genetic counseling
prenatal diagnosis


Coexistence of gene mutations causing Fabry disease and Duchenne muscular dystrophy in a Japanese boy.

Both Fabry disease and Duchenne muscular dystrophy were confirmed by gene analysis in a Japanese boy. He developed muscle weakness at 4 years of age. A muscle biopsy revealed lamellar inclusion bodies in vascular endothelial cells in addition to myopathic changes with negative dystrophin staining. The myopathic symptoms progressed, and he died of pneumonia at 24 years of age. No clinical manifestations of Fabry disease were observed except for hypohidrosis and angiokeratoma. However, glycolipid accumulation was found in biopsied renal tissue. Molecular analysis demonstrated two gene mutations; a novel single-base deletion in exon 3 of the alpha-galactosidase gene, and a dystrophin gene deletion extending from exon 46 to exon 50. His mother was confirmed to be heterozygous for both gene deletions.

Both

    Fabry disease
    DIAGNOSIS

 and

    Duchenne muscular dystrophy
    DIAGNOSIS

 were confirmed by

    gene analysis
    PARACLINICAL

 in a

    Japanese
    ETHNICITY

    boy
    GENDER

.

    He
    GENDER

 developed

    muscle weakness
    SYMPTOMS

 at

    4 years of age
    AGE

. A

    muscle biopsy
    PARACLINICAL

 revealed

    lamellar inclusion bodies in vascular endothelial cells
    MICROSCOPIC

 in addition to

    myopathic changes
    MICROSCOPIC

 with

    negative dystrophin staining
    NEG_FINDINGS

. The

    myopathic symptoms
    SYMPTOMS

 progressed, and

    he
    GENDER

    died
    SYMPTOMS

 of

    pneumonia
    DIAGNOSIS

 at

    24 years of age
    AGE

.

    No clinical manifestations of Fabry disease were observed
    NEG_FINDINGS

 except for

    hypohidrosis
    SYMPTOMS

 and

    angiokeratoma
    SYMPTOMS

. However,

    glycolipid accumulation was found in biopsied renal tissue
    MICROSCOPIC

.

    Molecular analysis
    PARACLINICAL

 demonstrated

    two gene mutations; a novel single-base deletion in exon 3 of the alpha-galactosidase gene, and a dystrophin gene deletion extending from exon 46 to exon 50
    GENETICS

.

    His
    GENDER

    mother was confirmed to be heterozygous for both gene deletions
    FAMILY

.

Fabry disease
Duchenne muscular dystrophy
pneumonia

muscle weakness
myopathic symptoms
died
hypohidrosis
angiokeratoma