Prediction of dystrophin phenotype by DNA analysis in Duchenne/Becker muscular dystrophy.

Allele-specific molecular diagnosis of Duchenne and Becker muscular dystrophies (DMD and BMD) has been largely dependent upon muscle biopsy for dystrophin protein assay. We performed lymphocyte DNA mutation analysis by polymerase chain reaction on 14 boys presenting with a clinical picture compatible with DMD or BMD. DNA analysis revealed that 12 of 14 boys had a deletion of the dystrophin gene, thus establishing the diagnosis of DMD/BMD. Furthermore, genotypes for 9 of 12 deletion patients permitted prediction of the specific allelic disorder (i.e., DMD or BMD). Subsequent dystrophin testing confirmed all of the DNA-based diagnoses. We propose that DNA mutation analysis be included in the initial evaluation of patients suspected of having DMD/BMD, thus potentially eliminating the need for muscle biopsy in the majority of patients.

    Allele-specific molecular diagnosis
    PARACLINICAL

 of

    Duchenne and Becker muscular dystrophies (DMD and BMD)
    DIAGNOSIS

 has been largely dependent upon

    muscle biopsy
    PARACLINICAL

 for

    dystrophin protein assay
    PARACLINICAL

. We performed

    lymphocyte DNA mutation analysis by polymerase chain reaction
    PARACLINICAL

 on 14

    boys
    GENDER

 presenting with a clinical picture compatible with

    DMD
    DIAGNOSIS

 or

    BMD
    DIAGNOSIS

.

    DNA analysis
    PARACLINICAL

 revealed that 12 of 14

    boys
    GENDER

 had a

    deletion of the dystrophin gene
    GENETICS

, thus establishing the diagnosis of

    DMD/BMD
    DIAGNOSIS

. Furthermore, genotypes for 9 of 12 deletion patients permitted prediction of the specific allelic disorder (i.e.,

    DMD
    DIAGNOSIS

 or

    BMD
    DIAGNOSIS

). Subsequent

    dystrophin testing
    PARACLINICAL

 confirmed all of the DNA-based diagnoses. We propose that

    DNA mutation analysis
    PARACLINICAL

 be included in the initial evaluation of patients suspected of having

    DMD/BMD
    DIAGNOSIS

, thus potentially eliminating the need for

    muscle biopsy
    PARACLINICAL

 in the majority of patients.


Premature chain termination mutation causing Duchenne muscular dystrophy.

We identified a premature chain termination mutation in two brothers with Duchenne muscular dystrophy and correlated the mutation in one of the brothers with immunologic detection of dystrophin in skeletal muscle. Southern and polymerase chain reaction (PCR) studies of genomic DNA from the affected boys showed no major gene rearrangements. However, the noted absence of a HindIII Southern fragment containing the proximal portion of exon 48 led to the identification of a point mutation that creates a new HindIII restriction site in that exon. Exon 48 was amplified by PCR from DNA of the patients and other family members and digested with HindIII to show the mutation in the two boys and also in their mother and maternal grandmother. Direct DNA sequencing demonstrated a cytosine-to-thymine transition at nucleotide 7163 of dystrophin that converts a glutamine codon (CAA) to an ochre chain termination codon (UAA). This mutation predicts a truncated dystrophin missing the distal spectrin-like repeat region, the cysteine-rich domain, and the carboxy terminal. Immunohistochemistry of skeletal muscle from one of the affected boys revealed membrane-localized dystrophin in the majority of fibers detected by anti-dystrophin antibodies against (1) the amino terminal and (2) part of the spectrin-like repeat region; both regions would be present in the truncated dystrophin predicted by the chain termination mutation. This suggests that the carboxy terminal may not be an absolute requirement for dystrophin membrane localization. Very few muscle fibers also showed peripheral immunostaining using anti-dystrophin antibodies against the carboxy terminal, suggesting gene reversion, suppression, or read-through in these rare fibers.

We identified a

    premature chain termination mutation
    GENETICS

 in two

    brothers
    GENDER

 with

    Duchenne muscular dystrophy
    DIAGNOSIS

 and correlated the

    mutation in one of the brothers
    FAMILY

 with

    immunologic detection of dystrophin in skeletal muscle
    BIOCHEMICAL

.

    Southern and polymerase chain reaction (PCR) studies of genomic DNA from
    PARACLINICAL

 the affected

    boys
    GENDER

 showed

    no major gene rearrangements
    NEG_FINDINGS

. However, the noted

    absence of a HindIII Southern fragment containing the proximal portion of exon 48
    GENETICS

 led to the identification of a

    point mutation that creates a new HindIII restriction site in that exon
    GENETICS

.

    Exon 48 was amplified by PCR from DNA of the patients and other family members and digested with HindIII
    PARACLINICAL

 to show

    the mutation in the two boys
    FAMILY

    and also in their mother and maternal grandmother
    FAMILY

.

    Direct DNA sequencing
    PARACLINICAL

 demonstrated a

    cytosine-to-thymine transition at nucleotide 7163 of dystrophin that converts a glutamine codon (CAA) to an ochre chain termination codon (UAA)
    GENETICS

. This

    mutation predicts a truncated dystrophin missing the distal spectrin-like repeat region, the cysteine-rich domain, and the carboxy terminal
    GENETICS

.

    Immunohistochemistry of skeletal muscle
    PARACLINICAL

 from one of the affected

    boys
    GENDER

 revealed

    membrane-localized dystrophin in the majority of fibers
    MICROSCOPIC

 detected by

    anti-dystrophin antibodies
    BIOCHEMICAL

 against (1) the amino terminal and (2) part of the spectrin-like repeat region;

    both regions would be present in the truncated dystrophin predicted by the chain termination mutation
    GENETICS

. This suggests that the carboxy terminal may not be an absolute requirement for dystrophin membrane localization. Very few

    muscle fibers
    MICROSCOPIC

 also showed peripheral immunostaining using

    anti-dystrophin antibodies against the carboxy terminal
    BIOCHEMICAL

, suggesting

    gene reversion
    GENETICS

, suppression, or read-through in these rare fibers.


A case of atypical Duchenne type muscular dystrophy with fragile X.

The patient was a 9-year-old boy. He began to walk at the age 1 year and 8 months and began to speak at the age of 2 years, suggesting retarded mental and motor development. A diagnosis of DMD was made when he was 7 years old. On admission, the patient exhibited a peculiar thin and long face, large auricles, narrow palate, malalignment of the teeth, epicanthus, saddle nose, and simian lines in addition to symptoms consistent with DMD. Chromosome analysis showed fragile X at Xq27 at a frequency of 20%. His mother also showed fragile X at the same position. Since the atypical features of this DMD patient are all explained as fragile X syndrome, this case was considered to be a very rare instance of DMD whose clinical pictures were modified by fragile X syndrome.

The patient was a

    9-year-old
    AGE

    boy
    GENDER

.

    He
    GENDER

 began to walk

    at the age 1 year and 8 months
    AGE

 and began to

    speak at the age of 2 years
    AGE

, suggesting

    retarded mental and motor development
    SYMPTOMS

. A diagnosis of

    DMD
    DIAGNOSIS

 was made when

    he
    GENDER

 was

    7 years old
    AGE

. On admission, the patient exhibited a

    peculiar thin and long face
    SYMPTOMS

,

    large auricles
    SYMPTOMS

,

    narrow palate
    SYMPTOMS

,

    malalignment of the teeth
    SYMPTOMS

,

    epicanthus
    SYMPTOMS

,

    saddle nose
    SYMPTOMS

, and

    simian lines
    SYMPTOMS

 in addition to

    symptoms consistent with DMD
    SYMPTOMS

.

    Chromosome analysis
    PARACLINICAL

 showed

    fragile X at Xq27 at a frequency of 20%
    GENETICS

.

    His
    GENDER

    mother also showed fragile X at the same position
    FAMILY

. Since the atypical features of this

    DMD
    DIAGNOSIS

 patient are all explained as

    fragile X syndrome
    DIAGNOSIS

, this case was considered to be a very rare instance of

    DMD
    DIAGNOSIS

 whose clinical pictures were modified by

    fragile X syndrome
    DIAGNOSIS

.

retarded mental and motor development
peculiar thin and long face
large auricles
narrow palate
malalignment of the teeth
epicanthus
saddle nose
simian lines
symptoms consistent with DMD

DMD
DMD
fragile X syndrome
DMD
fragile X syndrome


Prenatal diagnosis of Duchenne muscular dystrophy by fetal muscle biopsy.

Prenatal diagnosis and carrier detection for Duchenne muscular dystrophy (DMD) usually can be performed using DNA analysis. When recombination occurs within the DMD gene, or DNA analysis is uninformative, or in pedigrees where it is unclear whether or not the consultand is a carrier, direct examination of muscle by dystrophin analysis may provide the only means of prenatal diagnosis. We present three cases representing each of these molecular genetic diagnostic dilemmas. In each instance, we used sonographically guided fetal muscle biopsy for dystrophin protein analysis to resolve the dilemma. In the first and third cases, the presence of normal dystrophin was shown by immunofluorescence and this was followed by delivery of an unaffected male fetus. In the second case, dystrophin was not found in fetal muscle tissue implying that this fetus was affected. The absence of dystrophin and affected status was confirmed in skeletal and cardiac muscle obtained after pregnancy termination.

    Prenatal diagnosis
    PARACLINICAL

 and carrier detection for

    Duchenne muscular dystrophy (DMD)
    DIAGNOSIS

 usually can be performed using

    DNA analysis
    PARACLINICAL

. When

    recombination occurs within the DMD gene
    GENETICS

, or

    DNA analysis is uninformative
    NEG_FINDINGS

, or in

    pedigrees
    FAMILY

 where it is unclear whether or not the

    consultand is a carrier
    FAMILY

,

    direct examination of muscle by dystrophin analysis
    PARACLINICAL

 may provide the only means of prenatal diagnosis. We present three cases representing each of these molecular genetic diagnostic dilemmas. In each instance, we used

    sonographically guided fetal muscle biopsy for dystrophin protein analysis
    PARACLINICAL

 to resolve the dilemma. In the first and third cases, the

    presence of normal dystrophin
    NEG_FINDINGS

 was shown by

    immunofluorescence
    PARACLINICAL

 and this was followed by

    delivery of an unaffected male fetus
    MEDICATION

. In the second case,

    dystrophin was not found in fetal muscle tissue
    NEG_FINDINGS

 implying that this

    fetus
    AGE

 was affected. The

    absence of dystrophin and affected status
    SYMPTOMS

 was confirmed in

    skeletal and cardiac muscle
    SYMPTOMS

 obtained after

    pregnancy termination
    MEDICATION

.

delivery of an unaffected male fetus
pregnancy termination


Anesthesia-induced rhabdomyolysis in infants with unsuspected Duchenne dystrophy.

Anesthesia-induced rhabdomyolysis in infancy may represent an unsuspected Duchenne dystrophy. In order to establish the diagnosis of this genetic disease more definitively, a dystrophin test is a requisite following the conventional creatine kinase test and light and electron microscopies of the muscle biopsy.

    Anesthesia-induced rhabdomyolysis
    DIAGNOSIS

 in

    infancy
    AGE

 may represent an unsuspected

    Duchenne dystrophy
    DIAGNOSIS

. In order to establish the diagnosis of this

    genetic disease
    DIAGNOSIS

 more definitively, a

    dystrophin test
    PARACLINICAL

 is a requisite following the

    conventional creatine kinase test
    PARACLINICAL

 and

    light and electron microscopies of the muscle biopsy
    PARACLINICAL

.

Anesthesia-induced rhabdomyolysis
Duchenne dystrophy
genetic disease


Identification of a new DMD gene deletion by ectopic transcript analysis.

The detailed genetic analysis of the Duchenne/Becker muscular dystrophy gene is hindered by the large number of exons involved and their separation by huge introns. These problems can be overcome by the analysis of mRNA rather than genomic DNA and ectopic transcripts derived from peripheral blood lymphocytes provide a convenient source of material. Using reverse transcription and nested PCR, we show here a comprehensive strategy for the rapid and complete analysis of the coding sequences from complex genes and illustrate its potential by the identification of a hitherto undescribed single exon deletion.

The

    detailed genetic analysis
    PARACLINICAL

 of the

    Duchenne/Becker muscular dystrophy gene
    DIAGNOSIS

 is hindered by the large number of exons involved and their

    separation by huge introns
    GENETICS

. These problems can be overcome by the

    analysis of mRNA
    PARACLINICAL

 rather than

    genomic DNA
    PARACLINICAL

 and

    ectopic transcripts
    PARACLINICAL

 derived from

    peripheral blood lymphocytes
    MICROSCOPIC

 provide a convenient source of material. Using

    reverse transcription and nested PCR
    PARACLINICAL

, we show here a comprehensive strategy for the

    rapid and complete analysis of the coding sequences from complex genes
    PARACLINICAL

 and illustrate its potential by the identification of a

    hitherto undescribed single exon deletion
    GENETICS

.


An intact cysteine-rich domain is required for dystrophin function.

The carboxyl terminus of dystrophin is encoded by a highly conserved, alternatively spliced region of the gene. The few rare mutations reported in this region are of interest in unraveling the function of the dystrophin molecule. An unusual case of infantile onset Duchenne muscular dystrophy (DMD) with an internal 3' genomic deletion, and a membrane localized non-functional dystrophin protein, was used to explore the functional activity of this region. The patient's cDNA sequence showed an intragenic 1824-bp deletion precisely excising the cysteine rich and alternatively spliced COOH-terminal domains of dystrophin. The unaltered final 2.7 kb of the patients transcript was defined as a single exon localized to two genomic fragments, with the 5.9 kb HindIII fragment containing the stop codon. To understand the significance of deletions in this important region of the dystrophin gene, we mapped the order and cDNA coordinates for the 3' genomic HindIII fragments encoding the cysteine rich and alternative splicing domains. This 3' gene map was used to compare the clinical phenotype of the other reported COOH-terminal deletions in the literature. Our analysis concludes that the cysteine-rich domain confers an important function for the dystrophin protein.

The

    carboxyl terminus of dystrophin is encoded by a highly conserved, alternatively spliced region of the gene
    GENETICS

. The few rare mutations reported in this region are of interest in unraveling the function of the dystrophin molecule. An unusual case of

    infantile onset Duchenne muscular dystrophy (DMD)
    DIAGNOSIS

 with an

    internal 3' genomic deletion
    GENETICS

, and a

    membrane localized non-functional dystrophin protein
    MICROSCOPIC

, was used to explore the functional activity of this region. The patient's

    cDNA sequence
    PARACLINICAL

 showed an

    intragenic 1824-bp deletion precisely excising the cysteine rich and alternatively spliced COOH-terminal domains of dystrophin
    GENETICS

. The

    unaltered final 2.7 kb of the patients transcript was defined as a single exon localized to two genomic fragments, with the 5.9 kb HindIII fragment containing the stop codon
    GENETICS

. To understand the significance of

    deletions in
    GENETICS

 this important region

    of the dystrophin gene
    GENETICS

, we mapped the order and cDNA coordinates for the 3' genomic

    HindIII fragments encoding the cysteine rich and alternative splicing domains
    GENETICS

. This 3' gene map was used to compare the clinical phenotype of the other reported

    COOH-terminal deletions
    GENETICS

 in the literature. Our analysis concludes that the cysteine-rich domain confers an important function for the dystrophin protein.


Investigation of a female manifesting Becker muscular dystrophy.

Females manifesting Becker muscular dystrophy (BMD) are even more rarely observed than for the allelic condition Duchenne muscular dystrophy. The male proband has typical BMD with greatly raised CK activity and a myopathic muscle biopsy. His mother experienced walking difficulties from 35 years of age and has a myopathy with marked calf hypertrophy, a raised CK, and a myopathic muscle biopsy. Dystrophin analysis was undertaken on both the proband and his mother. Immunoblotting showed a protein of normal size but of reduced abundance in both. Immunocytochemical analysis in the proband indicated that the majority of the fibres showed weak dystrophin labelling and in his mother both dystrophin positive and dystrophin negative fibres were present. Non-random X inactivation at locus DXS255, was observed in DNA isolated from peripheral lymphocytes of the mother. Neither extended multiplex PCR performed on DNA from the proband nor analysis of lymphocyte derived mRNA showed a structural alteration in the dystrophin gene suggesting that an unusual mutation was responsible for BMD in this family.

    Females
    GENDER

 manifesting

    Becker muscular dystrophy (BMD)
    DIAGNOSIS

 are even more rarely observed than for the allelic condition

    Duchenne muscular dystrophy
    DIAGNOSIS

. The

    male
    GENDER

 proband has typical

    BMD
    DIAGNOSIS

 with

    greatly raised CK activity
    BIOCHEMICAL

 and a

    myopathic muscle biopsy
    SYMPTOMS

.

    His
    GENDER

    mother
    GENDER

 experienced

    walking difficulties
    SYMPTOMS

    from 35 years of age
    AGE

 and has a

    myopathy
    DIAGNOSIS

 with

    marked calf hypertrophy
    SYMPTOMS

, a

    raised CK
    BIOCHEMICAL

, and a

    myopathic muscle biopsy
    SYMPTOMS

.

    Dystrophin analysis
    PARACLINICAL

 was undertaken on both the proband and his

    mother
    GENDER

.

    Immunoblotting
    PARACLINICAL

 showed a

    protein of normal size but of reduced abundance in both
    BIOCHEMICAL

.

    Immunocytochemical analysis
    PARACLINICAL

 in the proband indicated that

    the majority of the fibres showed weak dystrophin labelling
    MICROSCOPIC

 and in his mother

    both dystrophin positive and dystrophin negative fibres were present
    MICROSCOPIC

.

    Non-random X inactivation at locus DXS255, was observed in DNA isolated from peripheral lymphocytes of the mother
    GENETICS

.

    Neither extended multiplex PCR performed on DNA from the proband
    PARACLINICAL

 nor

    analysis of lymphocyte derived mRNA
    PARACLINICAL

 showed a

    structural alteration in the dystrophin gene
    GENETICS

 suggesting that an

    unusual mutation
    GENETICS

 was responsible for

    BMD
    DIAGNOSIS

 in this family.

Becker muscular dystrophy (BMD)
Duchenne muscular dystrophy
BMD
myopathy
BMD

myopathic muscle biopsy
walking difficulties
marked calf hypertrophy
myopathic muscle biopsy


[Muscular dystrophy as a risk factor in anesthesia].

Three cases of muscular dystrophy are reported on (8 years, 4 months, 10 months) in which serious conditions arose under anaesthetic (bradycardia, asystolia, hyperkalemia, rising CPK). In the first two cases there was no way of avoiding a fatal outcome, but in the third case the child survived with no permanent damage. The cause of incidents of this kind is discussed first as being hyperkalemia due to acute rhabdomyolysis, and secondly malign hyperthermia. There were no indications of malign hyperthermia in this case. It is hardly possible to distinguish this in an acute clinical ward, as the clinical symptoms are very similar. If it is known that muscular dystrophy is present, depolarising relaxants should be given sparingly. This also applies, as the first case shows, for muscular dystrophy of the Becker type, which can on the whole be regarded as benign in comparison with progressive muscular dystrophy of the Duchenne type. In this instance a forensic and anaesthetic expert's opinion even had to be produced at the request of the Public Prosecutor. The post mortem was carried out under the heading of a possible "mistaken medical treatment" but there was no evidence to justify such an assumption.

Three cases of

    muscular dystrophy
    DIAGNOSIS

 are reported on (

    8 years, 4 months, 10 months
    AGE

) in which

    serious conditions
    SYMPTOMS

 arose under

    anaesthetic
    MEDICATION

 (

    bradycardia
    SYMPTOMS

,

    asystolia
    SYMPTOMS

,

    hyperkalemia
    BIOCHEMICAL

,

    rising CPK)
    BIOCHEMICAL

. In the first two cases there was

    no way of avoiding a fatal outcome
    NEG_FINDINGS

, but in the third case the

    child
    AGE

 survived with

    no permanent damage
    SYMPTOMS

. The cause of incidents of this kind is discussed first as being

    hyperkalemia
    BIOCHEMICAL

 due to

    acute rhabdomyolysis
    DIAGNOSIS

, and secondly

    malign hyperthermia
    DIAGNOSIS

. There were

    no indications of malign hyperthermia
    NEG_FINDINGS

 in this case. It is hardly possible to distinguish this in an acute clinical ward, as the

    clinical symptoms are very
    SYMPTOMS

 similar. If it is known that

    muscular dystrophy
    DIAGNOSIS

 is present,

    depolarising relaxants
    MEDICATION

 should be given sparingly. This also applies, as the first case shows, for

    muscular dystrophy of the Becker type
    DIAGNOSIS

, which can on the whole be regarded as

    benign
    DIAGNOSIS

 in comparison with

    progressive muscular dystrophy of the Duchenne type
    DIAGNOSIS

. In this instance a

    forensic and anaesthetic expert
    PARACLINICAL

's opinion even had to be produced at the request of the Public Prosecutor. The

    post mortem
    PARACLINICAL

 was carried out under the heading of a possible "

    mistaken medical treatment
    NEG_FINDINGS

" but there was

    no evidence to justify such an assumption
    NEG_FINDINGS

.

serious conditions
bradycardia
asystolia
no permanent damage
clinical symptoms are very


X inactivation and dystrophin studies in a t(X;12) female: evidence for biochemical normalization in Duchenne muscular dystrophy carriers.

A 4-year-old girl was identified with high creatine kinase (CK) values, and mild muscle weakness in a limb-girdle distribution. Results of dystrophin analysis of the muscle biopsy were consistent with a manifesting heterozygote for Duchenne muscular dystrophy. In peripheral lymphocytes she had a t(X;12) (p21.2;q24.33). Late DNA replication studies demonstrated inactivation of the normal X chromosome in 99.4% of cells. Dystrophin immunofluorescence showed 64% dystrophin-negative muscle fibers. Dystrophin content of muscle by immunoblot was approximately 5% of normal. The discordance between the percent of normal X inactivation and percent of dystrophin-negative cells may be explained by compensatory protection of dystrophin by rare nuclei with the normal X active in multi-nucleated muscle fibers with shared cytoplasm.

A

    4-year-old
    AGE

    girl
    GENDER

 was identified with

    high creatine kinase (CK) values
    BIOCHEMICAL

, and

    mild muscle weakness in a limb-girdle distribution
    SYMPTOMS

. Results of

    dystrophin analysis of the muscle biopsy
    PARACLINICAL

 were consistent with a

    manifesting heterozygote for Duchenne muscular dystrophy
    GENETICS

. In peripheral lymphocytes

    she
    GENDER

 had a

    t(X;12) (p21.2;q24.33)
    GENETICS

.

    Late DNA replication studies
    PARACLINICAL

 demonstrated

    inactivation of the normal X chromosome in 99.4% of cells
    GENETICS

.

    Dystrophin immunofluorescence
    PARACLINICAL

 showed

    64% dystrophin-negative muscle fibers
    MICROSCOPIC

.

    Dystrophin content of muscle by immunoblot was approximately 5% of normal
    BIOCHEMICAL

. The discordance between the

    percent of normal X inactivation
    BIOCHEMICAL

 and percent of

    dystrophin-negative cells
    BIOCHEMICAL

 may be explained by

    compensatory protection of dystrophin
    BIOCHEMICAL

 by

    rare nuclei with the normal X active in multi-nucleated muscle fibers with shared cytoplasm
    MICROSCOPIC

.


Case of the month: germline mosaicism in carriers of Duchenne muscular dystrophy.

Carrier testing in a Duchenne muscular dystrophy (DMD) family resulted in the identification of a case of germline mosaicism. Using dystrophin cDNA probes, this phenomenon was ascertained by the demonstration of a deletion junction fragment present in the DNA of the affected patient and one sister but absent in the mother's DNA. As a result of this finding carrier risk estimations, based on restriction fragment length polymorphism (RFLP) studies, were significantly altered. The case demonstrates the importance of cDNA deletion carrier testing and the counseling implications of germline mosaicism.

    Carrier testing
    PARACLINICAL

 in a

    Duchenne muscular dystrophy (DMD)
    DIAGNOSIS

 family resulted in the identification of a case of

    germline mosaicism
    GENETICS

. Using

    dystrophin cDNA probes
    PARACLINICAL

, this phenomenon was ascertained by the demonstration of a

    deletion junction fragment present in the DNA of the affected patient and one sister but absent in the mother's DNA
    FAMILY

. As a result of this finding carrier risk estimations, based on

    restriction fragment length polymorphism (RFLP) studies
    PARACLINICAL

, were significantly altered. The case demonstrates the importance of

    cDNA deletion carrier testing
    PARACLINICAL

 and the counseling implications of

    germline mosaicism
    GENETICS

.


Optimization of DNA extraction from formalin-fixed tissue and its clinical application in Duchenne muscular dystrophy.

The authors report a case of Duchenne muscular dystrophy in which a deletion was determined by multiplex polymerase chain reaction using postmortem tissue from a proband who died in 1985, 2 years before the cloning of the dystrophin gene. Several extraction methods were analyzed to determine optimal conditions for recovery of DNA from fixed tissue. Variables examined were tissue lysis times and temperatures, a simple salting-out procedure for purification of DNA, polymerase chain reaction amplification of crude lysate versus purified DNA, and lysis of different tissues and tissue quantities. Extracted DNA was analyzed spectrophotometrically, electrophoretically, and by its suitability for polymerase chain reaction amplification using exon flanking primers of the dystrophin gene. Lysis at 37 degrees C for less than 24 hours led to the recovery of predominantly low-molecular-weight DNA, which was unsuitable for polymerase chain reaction in this experience. Lysis at 54 degrees C consistently yielded visible, spoolable quantities of high-molecular-weight DNA in as little as 24 hours. Direct amplification of crude, unpurified lysates was unsuccessful. However, purified samples yielded consistent amplification products. The purification step was simplified by substituting a rapid salting-out procedure for organic extractions.

The authors report a case of

    Duchenne muscular dystrophy
    DIAGNOSIS

 in which a deletion was determined by

    multiplex polymerase chain reaction
    PARACLINICAL

 using

    postmortem tissue
    PARACLINICAL

 from a

    proband
    GENDER

 who

    died
    SYMPTOMS

 in 1985, 2 years before the cloning of the dystrophin gene. Several extraction methods were analyzed to determine optimal conditions for

    recovery of DNA from fixed tissue
    PARACLINICAL

. Variables examined were

    tissue lysis
    MEDICATION

 times and temperatures, a

    simple salting-out procedure for purification of DNA
    MEDICATION

,

    polymerase chain reaction amplification of crude lysate versus purified DNA
    PARACLINICAL

, and lysis of different tissues and tissue quantities.

    Extracted DNA was analyzed spectrophotometrically, electrophoretically
    PARACLINICAL

, and by its suitability for

    polymerase chain reaction amplification using exon flanking primers of the dystrophin gene
    PARACLINICAL

.

    Lysis at 37 degrees C for less than 24 hours
    MEDICATION

 led to the

    recovery of predominantly low-molecular-weight DNA
    MICROSCOPIC

, which was

    unsuitable for polymerase chain reaction
    NEG_FINDINGS

 in this experience.

    Lysis at 54 degrees C
    MEDICATION

 consistently yielded

    visible, spoolable quantities of high-molecular-weight DNA
    MICROSCOPIC

 in as little as 24 hours.

    Direct amplification of crude, unpurified lysates
    PARACLINICAL

    was unsuccessful
    NEG_FINDINGS

. However,

    purified samples
    PARACLINICAL

 yielded consistent amplification products. The purification step was simplified by substituting a

    rapid salting-out procedure for organic extractions
    MEDICATION

.


Phenotypic Duchenne muscular dystrophy with C-terminal domain.

We report a patient with X-linked muscular dystrophy who had rapidly progressive muscle weakness and became wheelchair-bound at age 10 years. Clinically, he was diagnosed as having Duchenne muscular dystrophy; however, he was diagnosed as having Becker muscular dystrophy by dystrophin tests using a C-terminal monoclonal antibody. No immunolabelling was observed with a monoclonal antibody against the N-terminal domain. Multiplex polymerase chain reaction analysis revealed the deletion of exons 3-19. The data suggest that the deletion of the N-terminal domain of dystrophin can cause a severe phenotype even when the C-terminus of the protein is well preserved.

We report a patient with

    X-linked
    GENETICS

    muscular dystrophy
    DIAGNOSIS

 who had

    rapidly progressive muscle weakness
    SYMPTOMS

 and became

    wheelchair-bound
    MEDICATION

 at

    age 10 years
    AGE

. Clinically,

    he
    GENDER

 was diagnosed as having

    Duchenne muscular dystrophy
    DIAGNOSIS

; however,

    he
    GENDER

 was diagnosed as having

    Becker muscular dystrophy
    DIAGNOSIS

 by

    dystrophin tests
    PARACLINICAL

 using a

    C-terminal monoclonal antibody
    PARACLINICAL

.

    No immunolabelling was observed with a monoclonal antibody against the N-terminal domain
    NEG_FINDINGS

.

    Multiplex polymerase chain reaction analysis
    PARACLINICAL

 revealed the

    deletion of exons 3-19
    GENETICS

. The data suggest that the

    deletion of the N-terminal domain of dystrophin
    GENETICS

 can cause a severe phenotype even when the C-terminus of the protein is well preserved.

muscular dystrophy
Duchenne muscular dystrophy
Becker muscular dystrophy


[The two brothers' case of dilated cardiomyopathy with benign Duchenne type of progressive muscular dystrophy (Becker's type)].

The presence of myocardial involvement is rare in benign Duchenne type of progressive muscular dystrophy (Becker's muscular dystrophy). We describe two brothers suffering from Becker's muscular dystrophy, both of whom presented with dilated cardiomyopathy. The first case is a 39-year-old male who had suffered from gait disturbance from the age of 17. When 37 years old, he was found to have heart disease. When he first came to our hospital, pseudohypertrophy of the calves was present. Chest radiography, electrocardiogram, ultrasonocardiography and clinical feature indicated Becker's muscular dystrophy with dilated cardiomyopathy. The second case is the younger brother of the 37-year old male. He suffered from leg weakness. He came to our hospital with the chief complaint of discomfort of the anterior chest. Pseudohypertrophy of the calves was present. Chest radiography, electrocardiogram, ultrasonogram indicated dilated cardiomyopathy.

The presence of

    myocardial involvement
    SYMPTOMS

 is rare in

    benign Duchenne type of progressive muscular dystrophy (Becker's muscular dystrophy)
    DIAGNOSIS

. We describe two

    brothers
    GENDER

 suffering from

    Becker's muscular dystrophy
    DIAGNOSIS

, both of whom presented with

    dilated cardiomyopathy
    DIAGNOSIS

. The first case is a

    39-year-old
    AGE

    male
    GENDER

 who had suffered from

    gait disturbance
    SYMPTOMS

 from the

    age of 17
    AGE

. When

    37 years old
    AGE

,

    he
    GENDER

 was found to have

    heart disease
    DIAGNOSIS

. When

    he
    GENDER

 first came to our hospital,

    pseudohypertrophy of the calves
    SYMPTOMS

 was present.

    Chest radiography
    PARACLINICAL

,

    electrocardiogram
    PARACLINICAL

,

    ultrasonocardiography
    PARACLINICAL

 and clinical feature indicated

    Becker's muscular dystrophy
    DIAGNOSIS

 with

    dilated cardiomyopathy
    DIAGNOSIS

. The second case is the

    younger brother
    AGE

 of the

    37-year old
    AGE

    male
    GENDER

.

    He
    GENDER

 suffered from

    leg weakness
    SYMPTOMS

.

    He
    GENDER

 came to our hospital with the chief complaint of

    discomfort of the anterior chest
    SYMPTOMS

.

    Pseudohypertrophy of the calves
    SYMPTOMS

 was present.

    Chest radiography
    PARACLINICAL

,

    electrocardiogram
    PARACLINICAL

,

    ultrasonogram
    PARACLINICAL

 indicated

    dilated cardiomyopathy
    DIAGNOSIS

.

myocardial involvement
gait disturbance
pseudohypertrophy of the calves
leg weakness
discomfort of the anterior chest
Pseudohypertrophy of the calves


Common sequence motifs at the rearrangement sites of a constitutional X/autosome translocation and associated deletion.

Reciprocal chromosome translocations are common de novo rearrangements that occur randomly throughout the human genome. To learn about causative mechanisms, we have cloned and sequenced the breakpoints of a cytologically balanced constitutional reciprocal translocation, t(X;4)(p21.2;q31.22), present in a girl with Duchenne muscular dystrophy (DMD). Physical mapping of the derivative chromosomes, after their separation in somatic cell hybrids, reveals that the translocation disrupts the DMD gene in Xp21 within the 18-kb intron 16. Restriction mapping and sequencing of clones that span both translocation breakpoints as well as the corresponding normal regions indicate the loss of approximately 5 kb in the formation of the derivative X chromosome, with 4-6 bp deleted from chromosome 4. RFLP and Southern analyses indicate that the de novo translocation is a paternal origin and that the father's X chromosome contains the DNA that is deleted in the derivative X. Most likely, deletion and translation arose simultaneously from a complex rearrangement event that involves three chromosomal breakpoints. Short regions of sequence homology were present at the three sites. A 5-bp sequence, GGAAT, found exactly at the translocation breakpoints on both normal chromosomes X and 4, has been preserved only on the der(4) chromosome. It is likely that the X-derived sequence GGAATCA has been lost in the formation of the der(X) chromosome, as it matches an inverted GAATCA sequence present on the opposite strand exactly at the other end of the deleted 5-kb fragment. These findings suggest a possible mechanism which may have juxtaposed the three sites and mediated sequence-specific breakage and recombination between nonhomologous chromosomes in male meiosis.

    Reciprocal chromosome translocations
    GENETICS

 are common

    de novo rearrangements
    GENETICS

 that occur randomly throughout the human genome. To learn about causative mechanisms, we have

    cloned and sequenced the
    PARACLINICAL

 breakpoints of a

    cytologically balanced constitutional reciprocal translocation, t(X;4)(p21.2;q31.22)
    GENETICS

, present in a

    girl
    GENDER

 with

    Duchenne muscular dystrophy (DMD)
    DIAGNOSIS

.

    Physical mapping of the derivative chromosomes
    PARACLINICAL

, after their separation in

    somatic cell hybrids
    MICROSCOPIC

, reveals that the

    translocation disrupts the DMD gene in Xp21 within the 18-kb intron 16
    GENETICS

.

    Restriction mapping and sequencing of clones that span both translocation breakpoints as well as the corresponding normal regions
    PARACLINICAL

 indicate the

    loss of approximately 5 kb in the formation of the derivative X chromosome, with 4-6 bp deleted from chromosome 4
    GENETICS

.

    RFLP and Southern analyses
    PARACLINICAL

 indicate that

    the de novo translocation is a paternal origin
    GENETICS

 and that the father's X chromosome contains the DNA that is deleted in the derivative X. Most likely,

    deletion and translation
    GENETICS

 arose simultaneously from a complex rearrangement event that involves three chromosomal breakpoints.

    Short regions of sequence homology were present at the three
    GENETICS

 sites.

    A 5-bp sequence, GGAAT, found exactly at the translocation breakpoints on both normal chromosomes X and 4, has been preserved only on the der(4) chromosome
    GENETICS

. It is likely that

    the X-derived sequence GGAATCA has been lost in the formation of the der(X) chromosome, as it matches an inverted GAATCA sequence present on the opposite strand exactly at the other end of the deleted 5-kb fragment
    GENETICS

. These findings suggest a possible mechanism which may have juxtaposed the three sites and mediated

    sequence-specific breakage and recombination between nonhomologous chromosomes
    GENETICS

 in

    male meiosis
    GENETICS

.


Point mutations in the dystrophin gene.

Defining the range of mutations in genes that cause human disease is essential to determine the mechanisms of genetic variation and the function of gene domains and to perform precise carrier and prenatal diagnosis. The mutations in one-third of Duchenne muscular dystrophy patients remain unknown as they do not involve gross rearrangements of the dystrophin gene. The size and complexity of the gene have prohibited the systematic definition of point mutations. We have developed a method for the identification of these mutations by nested amplification, chemical mismatch detection, and sequencing of reverse transcripts of trace amounts of dystrophin mRNA from peripheral blood lymphocytes. Analysis of the entire coding region (11 kilobases) in seven patients has resulted in detection of a sequence change in each case that is clearly sufficient to cause the disease. All mutations should cause premature translational termination, and the resulting phenotypes are thus equivalent to those caused by frameshifting deletions. The results support a particular functional importance for the C-terminal region of dystrophin. Application of this approach to mutation detection will extend direct carrier and prenatal diagnosis to virtually every affected family.

Defining the range of mutations in genes that cause human disease is essential to determine the mechanisms of genetic variation and the function of gene domains and to perform precise carrier and prenatal diagnosis. The mutations in one-third of

    Duchenne muscular dystrophy
    DIAGNOSIS

 patients remain unknown as they do not involve

    gross rearrangements of the dystrophin gene
    GENETICS

. The size and complexity of the gene have prohibited the systematic definition of point mutations. We have developed a method for the identification of these mutations by

    nested amplification
    PARACLINICAL

,

    chemical mismatch detection
    PARACLINICAL

, and

    sequencing of reverse transcripts of trace amounts of dystrophin mRNA from peripheral blood lymphocytes
    PARACLINICAL

.

    Analysis of the entire coding region (11 kilobases)
    PARACLINICAL

 in seven patients has resulted in detection of a

    sequence change in
    GENETICS

 each case that is clearly sufficient to cause the disease. All mutations should cause

    premature translational termination
    GENETICS

, and the resulting phenotypes are thus equivalent to those caused by

    frameshifting deletions
    GENETICS

. The results support a particular functional importance for the C-terminal region

    of dystrophin
    GENETICS

. Application of this approach to

    mutation detection
    PARACLINICAL

 will extend direct carrier and prenatal diagnosis to virtually every affected family.


[Intramuscular degeneration process in Duchenne muscular dystrophy--investigation by longitudinal MR imaging of the skeletal muscles].

Intramuscular degeneration process of Duchenne dystrophy skeletal muscles was investigated by longitudinal skeletal muscle imaging with high-field-strength NMR-CT of 1.5 Tesla. Thigh muscles in 10 cases ranging in age from 4 to 19 years were examined by T1-weighed longitudinal images (TR = 215-505 ms, TE = 19-20 ms). Following results were obtained: (1) Skeletal muscle degeneration was depicted as high signal intensity area reflecting its high fat contents. (2) These high signal intensity areas had a longitudinally streaky appearance in parallel direction with myofibers. (3) These findings were more prominent toward myotendon junction than muscle bellies. (4) Skeletal muscle degeneration progressed rapidly between 7 to 10 years of age, and reached a plateau after that.

    Intramuscular degeneration process
    MICROSCOPIC

 of

    Duchenne dystrophy skeletal muscles
    DIAGNOSIS

 was investigated by

    longitudinal skeletal muscle imaging
    PARACLINICAL

 with high

    -field-strength NMR-CT of 1.5 Tesla
    PARACLINICAL

.

    Thigh muscles
    PARACLINICAL

 in 10 cases ranging in

    age from 4 to 19 years
    AGE

 were examined by

    T1-weighed longitudinal images
    PARACLINICAL

 (TR = 215-505 ms, TE = 19-20 ms). Following results were obtained: (1)

    Skeletal muscle degeneration
    SYMPTOMS

 was depicted as

    high signal intensity area reflecting its high fat contents
    SYMPTOMS

. (2) These

    high signal intensity areas had a longitudinally streaky appearance in parallel direction with myofibers
    SYMPTOMS

. (3) These findings were more prominent

    toward myotendon junction than muscle bellies
    SYMPTOMS

. (4)

    Skeletal muscle degeneration
    SYMPTOMS

 progressed rapidly

    between 7 to 10 years of age
    AGE

, and reached a plateau after that.


A truncated dystrophin lacking the C-terminal domains is localized at the muscle membrane.

A Duchenne muscular dystrophy patient who displayed near-normal dystrophin staining at the sarcolemma with N-terminal, but not with C-terminal, anti-dystrophin monoclonal antibodies was found to have a frameshift deletion of exons 42 and 43. This deletion introduces an early termination codon, and a 225-kD protein was detected by western blotting with N-terminal antibodies only. The results suggest that an N-terminal truncated dystrophin fragment encoded by exon 1-41 is able to associate with the muscle cell membrane. The current idea that the C-terminal domains of dystrophin are important or essential for its integration with the sarcolemma may have to be reexamined in the light of these observations.

A

    Duchenne muscular dystrophy
    DIAGNOSIS

 patient who displayed

    near-normal dystrophin staining at the sarcolemma with N-terminal, but not with C
    NEG_FINDINGS

-terminal,

    anti-dystrophin monoclonal antibodies
    BIOCHEMICAL

 was found to have a

    frameshift deletion of exons 42 and 43
    GENETICS

. This

    deletion introduces an early termination codon
    GENETICS

, and a

    225-kD
    BIOCHEMICAL

 protein was detected by

    western blotting
    PARACLINICAL

 with

    N-terminal antibodies
    BIOCHEMICAL

 only. The results suggest that an

    N-terminal truncated dystrophin fragment encoded by exon 1-41
    GENETICS

 is able to associate with the

    muscle cell membrane
    MICROSCOPIC

. The current idea that the C-terminal domains of dystrophin are important or essential for its integration with the sarcolemma may have to be reexamined in the light of these observations.

anti-dystrophin monoclonal antibodies
225-kD
N-terminal antibodies


A homologue of dystrophin is expressed at the blood vessel membrane of DMD and BMD patients: immunological evidence.

Muscles from Becker muscular dystrophy (BMD) and Duchenne muscular dystrophy (DMD) patients were analysed using monoclonal and polyclonal antibodies raised against different regions of the dystrophin molecule. On blot, two of the antibodies detected a protein of Mr 400K in muscle extracts from all patients, including a BMD patient with a deletion which spanned more than 40% of the central rod domain of the Xp21 encoded dystrophin. Immunocytochemical labelling of tissue sections from the same patients showed that the same two antibodies labelled a protein at the surface membrane of smooth muscle fibers in blood vessels of both BMD and DMD muscles. Thus we have demonstrated a 400K blood vessel-associated protein, which is immunologically homologous with dystrophin, for at least two epitopes from the carboxy terminal and the central rod domains must be encoded by another gene than the dystrophin gene.

Muscles from

    Becker muscular dystrophy (BMD)
    DIAGNOSIS

 and

    Duchenne muscular dystrophy (DMD)
    DIAGNOSIS

 patients were analysed using monoclonal and polyclonal antibodies raised against different regions of the dystrophin molecule. On

    blot
    PARACLINICAL

, two of the antibodies detected a protein of Mr 400K

    in muscle extracts
    MICROSCOPIC

 from all patients, including a

    BMD
    DIAGNOSIS

 patient with a

    deletion which spanned more than 40% of the central rod domain of the Xp21 encoded dystrophin
    GENETICS

.

    Immunocytochemical labelling of tissue sections
    PARACLINICAL

 from the same patients showed that the same two antibodies

    labelled a protein at the surface membrane of smooth muscle fibers in blood vessels of both BMD and DMD muscles
    MICROSCOPIC

. Thus we have demonstrated a 400K

    blood vessel-associated
    MICROSCOPIC

 protein, which is immunologically homologous with dystrophin, for at least two epitopes

    from the carboxy terminal and the central rod
    GENETICS

 domains must be encoded by another

    gene than the dystrophin gene
    GENETICS

.

Becker muscular dystrophy (BMD)
Duchenne muscular dystrophy (DMD)
BMD


Dystrophin deficiency in a case of congenital myopathy.

We studied a 5-year-old boy who had the "floppy infant syndrome" and a dystrophic pattern on muscle biopsy. According to the clinical presentation and the histopathological findings the diagnosis of congenital muscular dystrophy with associated intellectual retardation was made. Immunohistochemical and immunoblot studies using anti-dystrophin antibodies showed complete absence of the protein in the patient's muscle. DNA analysis using cDNA probes showed a deletion at the 5' end of the dystrophin gene. Our observations on this patient suggest a new phenotypical variant of Duchenne muscular dystrophy.

We studied a

    5-year-old
    AGE

    boy
    GENDER

 who had the "

    floppy infant syndrome"
    SYMPTOMS

 and a

    dystrophic pattern
    SYMPTOMS

 on

    muscle biopsy
    PARACLINICAL

. According to the clinical presentation and the histopathological findings the diagnosis of

    congenital muscular dystrophy
    DIAGNOSIS

 with

    associated intellectual retardation
    SYMPTOMS

 was made.

    Immunohistochemical and immunoblot studies
    PARACLINICAL

 using

    anti-dystrophin antibodies
    PARACLINICAL

 showed

    complete absence of the protein in the patient's muscle
    MICROSCOPIC

.

    DNA analysis using cDNA probes
    PARACLINICAL

 showed a

    deletion at the 5' end of the dystrophin gene
    GENETICS

. Our observations on this patient suggest a new phenotypical variant of

    Duchenne muscular dystrophy
    DIAGNOSIS

.

floppy infant syndrome"
dystrophic pattern
associated intellectual retardation

congenital muscular dystrophy
Duchenne muscular dystrophy


Becker muscular dystrophy: detection of unusual disease courses by combined approach to dystrophin analysis.

The rapid progress of research on the structure of the dystrophin gene has enormously increased our understanding of the molecular basis of Duchenne (DMD) and Becker (BMD) muscular dystrophy. Apart from "classical" clinical presentations, asymptomatic or only mildly affected individuals with deletions in the dystrophin gene have now been reported. We describe two families which were initially classified as metabolic myopathies, until the diagnosis of atypical BMD was established after dystrophin analysis at the protein and DNA level. A modern diagnostic approach to myopathies should, therefore, not only include morphological and biochemical investigations, but also be extended to the analysis of the dystrophin gene.

The rapid progress of research on the structure of the dystrophin gene has enormously increased our understanding of the molecular basis of

    Duchenne (DMD)
    DIAGNOSIS

 and

    Becker (BMD) muscular dystrophy
    DIAGNOSIS

. Apart from "classical" clinical presentations,

    asymptomatic
    SYMPTOMS

 or only mildly affected individuals with

    deletions in the dystrophin gene
    GENETICS

 have now been reported. We describe two families which were

    initially classified as metabolic myopathies
    NEG_FINDINGS

, until the diagnosis of

    atypical BMD
    DIAGNOSIS

 was established after

    dystrophin analysis at the protein and DNA level
    PARACLINICAL

. A modern diagnostic approach to

    myopathies
    DIAGNOSIS

 should, therefore, not only include

    morphological and biochemical investigations
    PARACLINICAL

, but also be extended to the

    analysis of the dystrophin gene
    PARACLINICAL

.

Duchenne (DMD)
Becker (BMD) muscular dystrophy
atypical BMD
myopathies


Somatic mosaicism for a deletion of the dystrophin gene in a carrier of Becker muscular dystrophy.

Duchenne muscular dystrophy (DMD) and the allelic milder form of Becker muscular dystrophy (BMD) are caused by mutations of the dystrophin gene on the short arm of the X chromosome. One third of affected individuals are expected to result from de novo mutations. Genetic counselling of families with sporadic cases is complicated by the potential meiotic origin of the mutation in the mother resulting in germline mosaicism. Here we present direct evidence for combined somatic and germline mosaicism for a deletion of the dystrophin gene, thereby proving the mitotic origin of this deletion and pinpointing a further potential pitfall for genetic counselling. The mother of a BMD son and a BMD carrier daughter, both carrying a deletion of dystrophin cDNA 7 (0.5 kb Hind III fragment) and cDNA 8, was herself clinically healthy and had normal creatine kinase levels. A muscle specimen of the mother showed mild overall pathology as well as focal dystrophin deficiency. In contrast chromosomal in situ suppression (CISS) hybridization of metaphase chromosomes using a cosmid clone of the corresponding cDNA deleted in her son revealed no evidence of somatic mosaicism in their lymphocytes. These results emphasize the value of an approach correlating genetic and immunological data for the definition of a carrier state in BMD or DMD. The possibility of somatic mosaicism should be considered when genetic counselling of a family with a sporadic case of BMD or DMD is performed.

    Duchenne muscular dystrophy (DMD)
    DIAGNOSIS

 and the

    allelic milder form of Becker muscular dystrophy (BMD)
    DIAGNOSIS

 are caused by

    mutations of the dystrophin gene on the short arm of the X chromosome
    GENETICS

. One third of affected individuals are expected to result from

    de novo mutations
    GENETICS

.

    Genetic counselling
    PARACLINICAL

 of families with sporadic cases is complicated by the

    potential meiotic origin of the mutation in the mother
    GENETICS

 resulting in

    germline mosaicism
    GENETICS

. Here we present direct evidence for

    combined somatic and germline mosaicism for a deletion of the dystrophin gene
    GENETICS

, thereby proving the

    mitotic origin of this deletion
    GENETICS

 and pinpointing a further potential pitfall for genetic counselling. The

    mother of a BMD son and a BMD carrier daughter, both carrying a deletion of dystrophin cDNA 7 (0.5 kb Hind III fragment) and cDNA 8
    FAMILY

, was

    herself clinically healthy
    NEG_FINDINGS

 and had

    normal creatine kinase levels
    NEG_FINDINGS

. A

    muscle specimen of the mother
    PARACLINICAL

 showed

    mild overall pathology
    SYMPTOMS

 as well as

    focal dystrophin deficiency
    BIOCHEMICAL

. In contrast

    chromosomal in situ suppression (CISS) hybridization of metaphase chromosomes using a cosmid clone of the corresponding cDNA deleted in her son
    PARACLINICAL

 revealed

    no evidence of somatic mosaicism in their lymphocytes
    NEG_FINDINGS

. These results emphasize the value of an approach correlating genetic and immunological data for the definition of a carrier state in

    BMD
    DIAGNOSIS

 or

    DMD
    DIAGNOSIS

. The possibility of

    somatic mosaicism
    GENETICS

 should be considered when

    genetic counselling
    MEDICATION

 of a

    family with a sporadic case of BMD
    FAMILY

 or

    DMD
    DIAGNOSIS

 is performed.


Possible influences on the expression of X chromosome-linked dystrophin abnormalities by heterozygosity for autosomal recessive Fukuyama congenital muscular dystrophy.

Abnormalities of dystrophin, a cytoskeletal protein of muscle and nerve, are generally considered specific for Duchenne and Becker muscular dystrophy. However, several patients have recently been identified with dystrophin deficiency who, before dystrophin testing, were considered to have Fukuyama congenital muscular dystrophy (FCMD) on the basis of clinical findings. Epidemiologic data suggest that only 1/3500 males with autosomal recessive FCMD should have abnormal dystrophin. To explain the observation of 3/23 FCMD males with abnormal dystrophin, we propose that dystrophin and the FCMD gene product interact and that the earlier onset and greater severity of these patients' phenotype (relative to Duchenne muscular dystrophy) are due to their being heterozygous for the FCMD mutation in addition to being hemizygous for Duchenne muscular dystrophy, a genotype that is predicted to occur in 1/175,000 Japanese males. This model may help explain the genetic basis for some of the clinical and pathological variability seen among patients with FCMD, and it has potential implications for understanding the inheritance of other autosomal recessive disorders in general. For example, sex ratios for rare autosomal recessive disorders caused by mutations in proteins that interact with X chromosome-linked gene products may display predictable deviation from 1:1.

    Abnormalities of dystrophin
    BIOCHEMICAL

, a

    cytoskeletal protein of muscle and nerve
    MICROSCOPIC

, are generally considered specific for

    Duchenne
    DIAGNOSIS

 and

    Becker muscular dystrophy
    DIAGNOSIS

. However, several patients have recently been identified with

    dystrophin deficiency
    BIOCHEMICAL

 who, before

    dystrophin testing
    PARACLINICAL

, were considered to have

    Fukuyama congenital muscular dystrophy (FCMD)
    DIAGNOSIS

 on the basis of clinical findings. Epidemiologic data suggest that only 1/3500

    males
    GENDER

 with

    autosomal recessive FCMD
    DIAGNOSIS

 should have

    abnormal dystrophin
    BIOCHEMICAL

. To explain the observation of 3/23

    FCMD
    DIAGNOSIS

    males
    GENDER

 with

    abnormal dystrophin
    BIOCHEMICAL

, we propose that

    dystrophin and the FCMD gene product
    GENETICS

 interact and that the earlier onset and greater severity of these patients' phenotype (relative to

    Duchenne muscular dystrophy
    DIAGNOSIS

) are due to their being

    heterozygous for the FCMD mutation
    GENETICS

 in addition to being

    hemizygous for Duchenne muscular dystrophy
    FAMILY

, a genotype that is predicted to occur in 1/175,000

    Japanese
    ETHNICITY

    males
    GENDER

. This model may help explain the genetic basis for some of the clinical and pathological variability seen among patients with

    FCMD
    DIAGNOSIS

, and it has potential implications for understanding the inheritance of other

    autosomal recessive disorders
    GENETICS

 in general. For example, sex ratios for

    rare autosomal recessive disorders
    GENETICS

 caused by

    mutations in proteins that interact with X chromosome-linked gene products
    GENETICS

 may display predictable deviation from 1:1.

Abnormalities of dystrophin
dystrophin deficiency
abnormal dystrophin
abnormal dystrophin


Absence of malignant hyperthermia contractures in Becker-Duchenne dystrophy at age 2.

Two 2-year-old males underwent muscle biopsy that established the histopathologic diagnosis of Becker dystrophy in one, and Duchenne dystrophy in the other. Concomitant contracture testing with caffeine or halothane was normal for malignant hyperthermia (MH). The results suggest that acute hypermetabolism or acute rhabdomyolysis during anesthesia, in patients with these disorders, is related to the X-linked myopathy and its associated muscle deterioration, rather than to the autosomal dominant MH.

Two

    2-year-old
    AGE

    males
    GENDER

 underwent

    muscle biopsy
    PARACLINICAL

 that established the histopathologic diagnosis of

    Becker dystrophy
    DIAGNOSIS

 in one, and

    Duchenne dystrophy
    DIAGNOSIS

 in the other.

    Concomitant contracture testing with caffeine or halothane was normal for malignant hyperthermia (MH)
    NEG_FINDINGS

. The results suggest that

    acute hypermetabolism
    SYMPTOMS

 or

    acute rhabdomyolysis
    SYMPTOMS

 during

    anesthesia
    MEDICATION

, in patients with these disorders, is related to the

    X-linked myopathy
    GENETICS

 and its associated

    muscle deterioration
    SYMPTOMS

, rather than to the

    autosomal dominant MH
    DIAGNOSIS

.

Becker dystrophy
Duchenne dystrophy
autosomal dominant MH

acute hypermetabolism
acute rhabdomyolysis
muscle deterioration


Malignant hyperthermia and neuromuscular disease.

Malignant hyperthermia (MH) is a rare clinical syndrome characterized by hypermetabolism and triggered by specific anesthetic agents. The mechanism of this abnormal reaction is due to uncontrolled calcium flux in the skeletal muscles resulting in a variable clinical syndrome of muscle rigidity, respiratory and metabolic acidosis, and elevation of temperature. The specific genetic defect underlying this condition has not been identified in humans, though in susceptible swine a mutation of the gene for the ryanodine receptor, a large protein which comprises the calcium channel in the sarcoplasmic reticulum, has been identified recently. Inheritance in humans appears to be autosomal dominant with variable penetrance. Patients with MH rarely have physical or laboratory signs of muscle disease. However, scattered case reports and investigations of individuals with known myopathies and other muscle related problems, such as acute rhabdomyolysis or idiopathic persistently elevated creatine kinase, suggest a possible association of MH with a variety of neuromuscular diseases and stress syndromes. This association is very strong in the case of central core disease (CCD) where it is supported by clinical and laboratory evidence, including the proximity of the CCD gene to the ryanodine receptor gene on chromosome 19. A variety of other diseases have been implicated and can be classified as possibly associated (King-Denborough syndrome, Duchenne muscular dystrophy) or unlikely to be associated (myotonia congenita, sudden infant death syndrome, limb girdle dystrophy, neuroleptic malignant syndrome, etc.).(ABSTRACT TRUNCATED AT 250 WORDS)

    Malignant hyperthermia (MH)
    DIAGNOSIS

 is a rare clinical syndrome characterized by

    hypermetabolism
    SYMPTOMS

 and triggered by

    specific anesthetic agents
    MEDICATION

. The mechanism of this abnormal reaction is due to

    uncontrolled calcium flux in the skeletal muscles
    MICROSCOPIC

 resulting in a variable clinical syndrome of

    muscle rigidity
    SYMPTOMS

,

    respiratory and metabolic acidosis
    SYMPTOMS

, and

    elevation of temperature
    SYMPTOMS

. The specific

    genetic defect
    GENETICS

 underlying this condition has not been identified in humans, though in susceptible swine a

    mutation of the gene for the ryanodine receptor, a large protein which comprises the calcium channel in the sarcoplasmic reticulum
    GENETICS

, has been identified recently.

    Inheritance
    GENETICS

 in humans appears

    to be autosomal dominant
    GENETICS

 with

    variable penetrance
    GENETICS

. Patients with

    MH
    DIAGNOSIS

    rarely have physical or laboratory signs of muscle disease
    NEG_FINDINGS

. However, scattered case reports and investigations of individuals with known

    myopathies
    DIAGNOSIS

 and other

    muscle related problems
    SYMPTOMS

, such as

    acute rhabdomyolysis
    SYMPTOMS

 or

    idiopathic persistently elevated creatine kinase
    BIOCHEMICAL

, suggest a possible association of

    MH
    DIAGNOSIS

 with a variety of

    neuromuscular diseases
    DIAGNOSIS

 and

    stress syndromes
    DIAGNOSIS

. This association is very strong in the case of

    central core disease (CCD)
    DIAGNOSIS

 where it is supported by clinical and laboratory evidence, including the

    proximity of the CCD gene to the ryanodine receptor gene on chromosome 19
    GENETICS

. A variety of other diseases have been implicated and can be classified as possibly associated (

    King-Denborough syndrome
    DIAGNOSIS

,

    Duchenne muscular dystrophy
    DIAGNOSIS

) or unlikely to be associated (

    myotonia congenita
    DIAGNOSIS

,

    sudden infant death syndrome
    DIAGNOSIS

,

    limb girdle dystrophy
    DIAGNOSIS

,

    neuroleptic malignant syndrome
    DIAGNOSIS

, etc.).(ABSTRACT TRUNCATED AT 250 WORDS)

Malignant hyperthermia (MH)
MH
myopathies
MH
neuromuscular diseases
stress syndromes
central core disease (CCD)
King-Denborough syndrome
Duchenne muscular dystrophy
myotonia congenita
sudden infant death syndrome
limb girdle dystrophy
neuroleptic malignant syndrome

hypermetabolism
muscle rigidity
respiratory and metabolic acidosis
elevation of temperature
muscle related problems
acute rhabdomyolysis


A deletion including the brain promoter of the Duchenne muscular dystrophy gene is not associated with mental retardation.

A total of 161 unrelated Duchenne (DMD) and Becker muscular dystrophy (BMD) patients were screened for deletions in the brain promoter region of the dystrophin gene. Southern blot analysis using a probe for the brain promoter detected a deletion in this region in only one of the DMD families, in a patient with normal intelligence. This deletion also included the promoter of the muscle-type dystrophin and the exons encoding the actin-binding and part of the spectrin-like domains. Our data suggest that deletions in the brain promoter region are rare in DMD and are compatible with normal intelligence.

A total of 161 unrelated

    Duchenne (DMD)
    DIAGNOSIS

 and

    Becker muscular dystrophy (BMD)
    DIAGNOSIS

 patients were screened for

    deletions in the brain promoter region of the dystrophin gene
    GENETICS

.

    Southern blot analysis using a probe for the brain promoter
    PARACLINICAL

 detected a

    deletion in this
    GENETICS

 region in only one of the

    DMD
    DIAGNOSIS

 families, in a patient with

    normal intelligence
    NEG_FINDINGS

. This

    deletion also included the promoter of the muscle-type dystrophin and the exons encoding the actin-binding and part of the spectrin-like domains
    GENETICS

. Our data suggest that

    deletions in the brain promoter region
    GENETICS

 are rare in

    DMD
    DIAGNOSIS

 and are compatible with

    normal intelligence
    NEG_FINDINGS

.

Duchenne (DMD)
Becker muscular dystrophy (BMD)
DMD
DMD


A symptomatic female patient with Duchenne muscular dystrophy diagnosed by dystrophin-staining: a case report.

We report a case of symptomatic carrier of Duchenne muscular dystrophy (DMD) in a 14-year-old girl with no prior family history of DMD. She presented with chest pain, enlarged calf muscles, an elevated serum creatine kinase (CK), and decreased left ventricular function. Histological examination of skeletal muscle revealed myopathic changes and immunostaining with anti-dystrophin antiserum demonstrated a mosaic pattern which are compatible with the observations in carriers of DMD. Southern blots using the dystrophin cDNA revealed no evidence of a deletion within the DMD gene in the patient or in her mother. We found this observation interesting for two reasons: 1. Cardiomyopathy is rare in female DMD patients. 2. Immunostaining of a muscle biopsy with anti-dystrophin serum proved to be valuable in the diagnosed for symptomatic carriers of the dystrophin gene mutation.

We report a case of

    symptomatic carrier of Duchenne muscular dystrophy (DMD)
    DIAGNOSIS

 in a

    14-year-old
    AGE

    girl
    GENDER

 with

    no prior family history of DMD
    NEG_FINDINGS

.

    She
    GENDER

 presented with

    chest pain
    SYMPTOMS

,

    enlarged calf muscles
    SYMPTOMS

, an

    elevated serum creatine kinase (CK)
    BIOCHEMICAL

, and

    decreased left ventricular function
    SYMPTOMS

.

    Histological examination of skeletal muscle
    PARACLINICAL

 revealed

    myopathic changes
    MICROSCOPIC

 and

    immunostaining with anti-dystrophin antiserum
    PARACLINICAL

 demonstrated a

    mosaic pattern
    MICROSCOPIC

 which are compatible with the observations in carriers of

    DMD
    DIAGNOSIS

.

    Southern blots using the dystrophin cDNA
    PARACLINICAL

 revealed

    no evidence of a deletion within the DMD gene in the patient or in her mother
    NEG_FINDINGS

. We found this observation interesting for two reasons: 1.

    Cardiomyopathy
    DIAGNOSIS

 is rare in

    female
    GENDER

    DMD
    DIAGNOSIS

 patients. 2.

    Immunostaining of a muscle biopsy with anti-dystrophin serum
    PARACLINICAL

 proved to be valuable in the diagnosed for symptomatic carriers of the

    dystrophin gene mutation
    GENETICS

.

chest pain
enlarged calf muscles
decreased left ventricular function


[Surgical treatment of spinal deformities in Duchenne muscular dystrophy].

Forty seven Duchenne Muscular Dystrophy patients, operated on for spinal deformity with segmental spinal instrumentation according to Luque's technique, are reviewed with a mean post-operative follow up of 4 years 4 months. The study of the results obviously showed the interest of Luque Galveston technique for the treatment of severe curves with pelvic obliquity, whereas Dove's rectangle is an interesting choice for the early instrumentation. A total spinal arthrodesis can probably be avoided in these patients, which often demonstrate a satisfying spontaneous fusion after instrumentation. The general and mechanical complications are described, according to the consequences they have on the management technique of these patients.

Forty seven

    Duchenne Muscular Dystrophy
    DIAGNOSIS

 patients,

    operated on
    MEDICATION

 for

    spinal deformity
    DIAGNOSIS

 with

    segmental spinal instrumentation according to Luque's technique
    MEDICATION

, are reviewed with a mean post-operative follow up of 4

    years 4 months
    AGE

. The study of the results obviously showed the interest of

    Luque Galveston technique
    MEDICATION

 for the treatment of

    severe curves
    SYMPTOMS

 with

    pelvic obliquity
    SYMPTOMS

, whereas

    Dove's rectangle
    MEDICATION

 is an interesting choice for the

    early instrumentation
    MEDICATION

. A

    total spinal arthrodesis
    MEDICATION

 can probably be avoided in these patients, which often demonstrate a

    satisfying spontaneous fusion
    SYMPTOMS

 after

    instrumentation
    MEDICATION

. The general and mechanical complications are described, according to the consequences they have on the management technique of these patients.

Duchenne Muscular Dystrophy
spinal deformity

severe curves
pelvic obliquity
satisfying spontaneous fusion


Autosomal recessive Duchenne-like muscular dystrophy: molecular and histochemical results.

An autosomal recessive disorder which mimics Duchenne muscular dystrophy has long been suspected as a cause of muscular dystrophy in karyotypically normal girls and in both boys and girls with consanguineous parents. Analysis of dystrophin now allows confirmation of the existence of this disorder. We report the results of this analysis in a brother and sister who have the typical clinical features of Duchenne muscular dystrophy, but no demonstrable abnormality in dystrophin or its gene.

An

    autosomal recessive disorder
    GENETICS

 which mimics

    Duchenne muscular dystrophy
    DIAGNOSIS

 has long been suspected as a cause of

    muscular dystrophy
    DIAGNOSIS

 in

    karyotypically normal
    NEG_FINDINGS

    girls
    GENDER

 and in both

    boys
    GENDER

 and

    girls
    GENDER

 with

    consanguineous parents
    FAMILY

.

    Analysis of dystrophin
    PARACLINICAL

 now allows confirmation of the existence of this disorder. We report the results of this analysis in a

    brother and sister who have the typical clinical features of Duchenne muscular dystrophy
    FAMILY

, but

    no demonstrable abnormality in dystrophin or its gene
    NEG_FINDINGS

.

Duchenne muscular dystrophy
muscular dystrophy


Continuous subarachnoid analgesia in two adolescents with severe scoliosis and impaired pulmonary function.

We report postoperative pain management of two adolescents after upper abdominal procedures, one with Hurler-Scheie syndrome and a second with Duchenne muscular dystrophy, and both had progressive spinal scoliosis with poor pulmonary function. A combined technique of subarachnoid and general anesthesia was used during surgery. Postoperative administration of small intermittent doses of subarachnoid morphine produced profound analgesia, which eliminated the need for systemic opioids, restored preoperative arterial oxygenation within 48 hours after the operation, and expedited postoperative recovery.

We report

    postoperative pain management
    MEDICATION

 of two

    adolescents
    AGE

 after

    upper abdominal procedures
    MEDICATION

, one with

    Hurler-Scheie syndrome
    DIAGNOSIS

 and a second with

    Duchenne muscular dystrophy
    DIAGNOSIS

, and both had

    progressive spinal scoliosis
    SYMPTOMS

 with

    poor pulmonary function
    SYMPTOMS

. A

    combined technique of subarachnoid and general anesthesia
    MEDICATION

 was used during

    surgery
    MEDICATION

.

    Postoperative administration of small intermittent doses of subarachnoid morphine
    MEDICATION

 produced

    profound analgesia
    MEDICATION

, which

    eliminated the need for systemic opioids
    NEG_FINDINGS

,

    restored preoperative arterial oxygenation within 48 hours after the operation
    SYMPTOMS

, and

    expedited postoperative recovery
    MEDICATION

.

Hurler-Scheie syndrome
Duchenne muscular dystrophy


[Exercise-induced myalgia and high CKemia with a deletion in the dystrophin gene].

A 30-year-old man showed exercise-induced myalgia, calf muscle hypertrophy and high serum creatine kinase level, without muscular weakness. The symptoms began in childhood and did not progress. Electromyographic findings were consistent with myopathy, and the muscle histology showed nonspecific myopathic changes without evidence of storage of glycogen or lipid. Immunohistochemical staining with antibodies raised against three different dystrophin peptides revealed proper subcellular localization of dystrophin at the sarcolemma of all myofibers, but the intensity of the stain was decreased. Western blot analysis using the same antibodies revealed normal dystrophin in size, but showed the reduced amount of the protein. The DNA obtained from the patient's peripheral leukocyte showed a deletion of the dystrophin gene including exon 45 by using PCR technique. Though the detailed size and portion of the deleted gene are not ascertained, the deletion in this case may not severely affect the function of dystrophin, unlike cases of Duchenne or Becker muscular dystrophy. Dystrophin analysis is useful for the etiologic diagnosis in cases of myalgia and high CKemia.

A

    30-year-old
    AGE

    man
    GENDER

 showed

    exercise-induced myalgia
    SYMPTOMS

,

    calf muscle hypertrophy
    SYMPTOMS

 and

    high serum creatine kinase level
    BIOCHEMICAL

,

    without muscular weakness
    NEG_FINDINGS

. The symptoms began in

    childhood
    AGE

 and did not progress.

    Electromyographic findings
    PARACLINICAL

 were consistent with

    myopathy
    DIAGNOSIS

, and the

    muscle histology
    PARACLINICAL

 showed

    nonspecific myopathic changes
    SYMPTOMS

    without evidence of storage of glycogen or lipid
    NEG_FINDINGS

.

    Immunohistochemical staining
    PARACLINICAL

 with antibodies raised against three different dystrophin peptides revealed

    proper subcellular localization of dystrophin at the sarcolemma of all myofibers
    MICROSCOPIC

, but the

    intensity of the stain was decreased
    SYMPTOMS

.

    Western blot analysis
    PARACLINICAL

 using the same antibodies revealed

    normal dystrophin in size
    NEG_FINDINGS

, but showed the

    reduced amount of the protein
    BIOCHEMICAL

. The

    DNA obtained from the patient's peripheral leukocyte
    PARACLINICAL

 showed a

    deletion of the dystrophin gene including exon 45
    GENETICS

 by using

    PCR technique
    PARACLINICAL

. Though the detailed size and portion of the deleted gene are not ascertained, the deletion in this case may

    not severely affect the function of dystrophin
    NEG_FINDINGS

, unlike cases of

    Duchenne
    DIAGNOSIS

 or

    Becker muscular dystrophy
    DIAGNOSIS

.

    Dystrophin analysis
    PARACLINICAL

 is useful for the etiologic diagnosis in cases of

    myalgia
    SYMPTOMS

 and

    high CKemia
    BIOCHEMICAL

.

exercise-induced myalgia
calf muscle hypertrophy
nonspecific myopathic changes
intensity of the stain was decreased
myalgia

high serum creatine kinase level
reduced amount of the protein
high CKemia

myopathy
Duchenne
Becker muscular dystrophy


Is the carboxyl-terminus of dystrophin required for membrane association? A novel, severe case of Duchenne muscular dystrophy.

Duchenne muscular dystrophy is a lethal X-linked recessive disorder caused by the deficiency of a component of the muscle fiber membrane cytoskeleton called dystrophin. Becker muscular dystrophy, a clinically milder disorder, results from dystrophin abnormalities rather than deficiency. We identified the first patient who is clearly an exception to these established clinical and biochemical correlates. The patient described clinically had particularly severe Duchenne dystrophy. Biochemically, his muscle contained substantial amounts of abnormal dystrophin (Becker-like). Characterization of the dystrophin protein and gene revealed a unique intragenic gene deletion resulting in a dystrophin protein missing the carboxyl-terminal domain. This patient's dystrophin seemed to have a deleterious "dominant" effect on his muscle: The presence of this abnormal protein was more damaging to the myofibers than the absence of dystrophin would have been. This patient challenges the current hypothesis that dystrophin associates with the plasma membrane solely via its carboxyl-terminus, yet supports the hypothesis that an intact carboxyl-terminus is crucial for correct dystrophin function.

    Duchenne muscular dystrophy
    DIAGNOSIS

 is a

    lethal X-linked recessive disorder
    GENETICS

 caused by the

    deficiency of
    BIOCHEMICAL

 a component

    of the muscle fiber membrane cytoskeleton
    MICROSCOPIC

 called

    dystrophin
    BIOCHEMICAL

.

    Becker muscular dystrophy
    DIAGNOSIS

, a clinically milder disorder, results from

    dystrophin abnormalities
    BIOCHEMICAL

 rather than

    deficiency
    BIOCHEMICAL

. We identified the first patient who is clearly an exception to these established clinical and biochemical correlates. The patient described clinically had

    particularly severe Duchenne dystrophy
    DIAGNOSIS

. Biochemically, his

    muscle contained substantial amounts of abnormal dystrophin (Becker-like)
    MICROSCOPIC

.

    Characterization of the dystrophin protein and gene
    PARACLINICAL

 revealed a

    unique intragenic gene deletion resulting in a dystrophin protein missing the carboxyl-terminal domain
    GENETICS

. This patient's dystrophin seemed

    to have a deleterious "dominant" effect on his muscle
    SYMPTOMS

: The

    presence of this abnormal protein was more damaging to the myofibers
    SYMPTOMS

 than the

    absence of dystrophin
    NEG_FINDINGS

 would have been. This patient challenges the current hypothesis that dystrophin associates with the plasma membrane solely via its carboxyl-terminus, yet supports the hypothesis that an intact carboxyl-terminus is crucial for correct dystrophin function.

Duchenne muscular dystrophy
Becker muscular dystrophy
particularly severe Duchenne dystrophy

deficiency of
dystrophin
dystrophin abnormalities
deficiency


Dystrophin immunohistochemistry in a symptomatic carrier of Becker muscular dystrophy.

Immunohistochemical localization of dystrophin was studied in a symptomatic carrier of Becker muscular dystrophy (BMD). Muscle biopsy specimens from a female carrier showed findings compatible with slowly progressive muscular dystrophy by ordinary histochemical examinations. Immunohistochemical study, using an antiserum raised against a synthetic peptide fragment of dystrophin, demonstrated a mixture of staining patterns, including continuous but faint positive fibres, partially disrupted fibres and negative fibres. These findings were identical to those of patients with BMD and appear to differ from previous findings in female carriers of Duchenne muscular dystrophy. This report is the first immunohistochemical study of a symptomatic female proven by molecular genetic analysis to be a carrier of BMD.

    Immunohistochemical localization of dystrophin
    PARACLINICAL

 was studied in a symptomatic carrier of

    Becker muscular dystrophy (BMD)
    DIAGNOSIS

.

    Muscle biopsy specimens
    PARACLINICAL

 from a

    female
    GENDER

 carrier showed findings compatible with

    slowly progressive muscular dystrophy
    DIAGNOSIS

 by

    ordinary histochemical examinations
    PARACLINICAL

.

    Immunohistochemical study
    PARACLINICAL

, using an antiserum raised against a synthetic peptide fragment of dystrophin, demonstrated a

    mixture of staining patterns, including continuous but faint positive fibres, partially disrupted fibres and negative fibres
    MICROSCOPIC

. These findings were identical to those of patients with

    BMD
    DIAGNOSIS

 and appear to differ from previous findings in

    female
    GENDER

 carriers of

    Duchenne muscular dystrophy
    DIAGNOSIS

. This report is the first

    immunohistochemical study
    PARACLINICAL

 of a symptomatic

    female
    GENDER

 proven by

    molecular genetic analysis
    PARACLINICAL

 to be a carrier of

    BMD
    DIAGNOSIS

.

Becker muscular dystrophy (BMD)
slowly progressive muscular dystrophy
BMD
Duchenne muscular dystrophy
BMD


In utero fetal muscle biopsy for the diagnosis of Duchenne muscular dystrophy.

Deoxyribonucleic acid techniques can be used to diagnose Duchenne muscular dystrophy prenatally in male fetuses that are at risk. Deoxyribonucleic acid-based prenatal diagnosis can be impossible when there is only one prior affected male and there is no identifiable deletion or alteration. We performed fetal muscle biopsy in utero in such a case and documented the presence of dystrophin, thereby confirming normality in a male fetus at risk. This first in utero experience adds fetal muscle biopsy to the available procedures for fetal tissue diagnosis.

    Deoxyribonucleic acid techniques
    PARACLINICAL

 can be used to diagnose

    Duchenne muscular dystrophy
    DIAGNOSIS

    prenatally
    AGE

 in

    male
    GENDER

    fetuses
    AGE

 that are at risk.

    Deoxyribonucleic acid-based prenatal diagnosis
    PARACLINICAL

 can be impossible when there is only one prior affected

    male
    GENDER

 and there is

    no identifiable deletion or alteration
    NEG_FINDINGS

. We performed

    fetal muscle biopsy
    PARACLINICAL

 in

    utero
    AGE

 in such a case and documented the

    presence of dystrophin
    BIOCHEMICAL

, thereby confirming normality in a

    male
    GENDER

    fetus
    AGE

 at risk. This first in utero experience adds

    fetal muscle biopsy
    PARACLINICAL

 to the available procedures for

    fetal tissue diagnosis
    PARACLINICAL

.


The impact of Duchenne muscular dystrophy on families.

To understand the experiences of families having a child with Duchenne muscular dystrophy, the investigator studied three families for 10 weeks with a follow-up at 1 year. Six themes recurred in the common experiences in the families: the erosion of hope for normalcy; society's confirmation of the impossibility of normalcy; the dynamics of the family; a smaller world; letting go or hanging on; and things must change. This article illustrates these six themes, compares them to Roy's Adaptation Model, and discusses nursing interventions.

To understand the experiences of families having a

    child
    AGE

 with

    Duchenne muscular dystrophy
    DIAGNOSIS

, the investigator studied three families for 10 weeks with a

    follow-up
    PARACLINICAL

 at 1 year. Six themes recurred in the common experiences in the families: the

    erosion of hope for normalcy
    SYMPTOMS

; society's

    confirmation of the impossibility of normalcy
    SYMPTOMS

; the dynamics of the family; a smaller world; letting go or hanging on; and things must change. This article illustrates these six themes, compares them to Roy's Adaptation Model, and discusses

    nursing interventions
    MEDICATION

.


Duchenne muscular dystrophy in a girl identified by dystrophin deficiency.

We report an isolated case of a girl aged three years six months with Duchenne muscular dystrophy. Analysis of the patient's DNA with a probe covering the DNA gene revealed no deletion. Dystrophin, studied in biopsied muscle from the patient, using antidystrophin antibody in combination with immunofluorescence, was nearly completely absent. In this sporadic case of female muscular dystrophy, the identification of dystrophin-deficient muscle fibers made it possible to establish an accurate diagnosis of DMD affected female.

We report an isolated case of a

    girl
    GENDER

    aged three years six months
    AGE

 with

    Duchenne muscular dystrophy
    DIAGNOSIS

.

    Analysis of the patient's DNA with a probe covering the DNA gene
    PARACLINICAL

 revealed

    no deletion
    GENETICS

. Dystrophin,

    studied in biopsied muscle
    PARACLINICAL

 from the patient, using

    antidystrophin antibody in combination with immunofluorescence
    PARACLINICAL

,

    was nearly completely absent
    BIOCHEMICAL

. In this sporadic case of

    female
    GENDER

    muscular dystrophy
    DIAGNOSIS

, the identification of

    dystrophin-deficient muscle fibers
    MICROSCOPIC

 made it possible to establish an accurate diagnosis of

    DMD
    DIAGNOSIS

 affected

    female
    GENDER

.

Duchenne muscular dystrophy
muscular dystrophy
DMD


Immunohistochemical studies show truncated dystrophins in the myotubes of three fetuses at risk for Duchenne muscular dystrophy.

We have performed immunohistochemical studies on muscle tissue of three 12 week old fetuses at risk for DMD, using antisera directed against regions located NH2-proximally and centrally in the rod shaped spectrin-like domain and against the COOH-terminus of dystrophin. All three fetuses had a family history of DMD. Truncated dystrophins were identified in all three cases by a positive reaction with the NH2-proximal antibody, different reactions with the central antibody, and a negative reaction with the COOH-terminal antibody. These data indicate that a panel of antibodies would, in principle, permit 'immunological' mapping of dystrophin mutations. This is diagnostically important in the 35% of families where no mutation is detectable at the DNA level. Secondly, by using this mapping technique it may also become possible to identify the at risk haplotype when DNA analysis is not informative. This may be of great value in DMD carrier detection.

We have performed

    immunohistochemical studies on muscle tissue
    PARACLINICAL

 of three

    12 week old
    AGE

    fetuses
    AGE

 at risk for

    DMD
    DIAGNOSIS

, using antisera directed against regions located NH2-proximally and centrally in the rod shaped spectrin-like domain and against the COOH-terminus of dystrophin. All three

    fetuses
    AGE

    had a family history of DMD
    FAMILY

.

    Truncated dystrophins
    BIOCHEMICAL

 were identified in all three cases by a

    positive reaction with the NH2-proximal antibody
    BIOCHEMICAL

, different reactions with the central antibody, and a

    negative reaction with the COOH-terminal antibody
    NEG_FINDINGS

. These data indicate that a panel of antibodies would, in principle, permit '

    immunological' mapping of dystrophin mutations
    PARACLINICAL

. This is diagnostically important in the 35% of families where

    no mutation is detectable at the DNA level
    NEG_FINDINGS

. Secondly, by using this mapping technique it may also become possible to identify the at risk haplotype when

    DNA analysis is not informative
    NEG_FINDINGS

. This may be of great value in

    DMD
    DIAGNOSIS

 carrier detection.


Dystrophin deficiency in young girls with sporadic myopathy and normal karyotype.

We studied dystrophin in three young girls with a sporadic myopathy of early onset, manifested by mild to severe limb weakness, calf hypertrophy, high serum creatine kinase, normal karyotype, and morphologic features in muscle consistent with muscular dystrophy. DNA analysis did not reveal a deletion of the dystrophin gene. Immunohistochemical studies of dystrophin in muscle biopsies showed a mosaic of fibers with and without dystrophin, and immunoblot analysis showed partial dystrophin deficiency in all three patients, more severe in the patient with the highest proportion of dystrophin-deficient fibers. These observations suggest that the patients are Duchenne muscular dystrophy carriers. The data also support the concept that uneven lyonization in muscle is responsible for the clinical myopathy in these patients. We suggest that any girl with sporadic proximal limb weakness should be evaluated as a possible Duchenne carrier by dystrophin studies.

We studied dystrophin in three

    young
    AGE

    girls
    GENDER

 with a

    sporadic myopathy
    DIAGNOSIS

    of early onset
    SYMPTOMS

, manifested by

    mild to severe limb weakness
    SYMPTOMS

,

    calf hypertrophy
    SYMPTOMS

,

    high serum creatine kinase
    BIOCHEMICAL

,

    normal karyotype
    NEG_FINDINGS

, and

    morphologic features in muscle consistent with muscular dystrophy
    SYMPTOMS

.

    DNA analysis
    PARACLINICAL

    did not reveal a deletion of the dystrophin gene
    NEG_FINDINGS

.

    Immunohistochemical studies of dystrophin in muscle biopsies
    PARACLINICAL

 showed a

    mosaic of fibers with and without dystrophin
    MICROSCOPIC

, and

    immunoblot analysis
    PARACLINICAL

 showed

    partial dystrophin deficiency
    BIOCHEMICAL

 in all three patients, more severe in the patient with the

    highest proportion of dystrophin-deficient fibers
    MICROSCOPIC

. These observations suggest that the patients are

    Duchenne muscular dystrophy
    DIAGNOSIS

 carriers. The data also support the concept that

    uneven lyonization in muscle
    MICROSCOPIC

 is responsible for the

    clinical myopathy
    SYMPTOMS

 in these patients. We suggest that any

    girl
    GENDER

 with

    sporadic proximal limb weakness
    SYMPTOMS

 should be evaluated as a possible

    Duchenne
    DIAGNOSIS

 carrier by

    dystrophin studies
    PARACLINICAL

.

sporadic myopathy
Duchenne muscular dystrophy
Duchenne

high serum creatine kinase
partial dystrophin deficiency


Congenital muscular dystrophy in Marinesco-Sjögren syndrome.

The histochemical and immunocytochemical findings of biopsied muscle in a 2-year-old girl with Marinesco-Sjögren syndrome are reported. Muscle histology consisted of mild muscular dystrophy, such as that found in limb-girdle or non-Fukuyama congenital muscular dystrophy. By immunocytochemical stain using anti-dystrophin antibody, Duchenne and Becker muscular dystrophies were excluded. In addition to characteristic clinical features, including ataxia, congenital cataract, and psychomotor retardation, muscle involvement is essential to the diagnosis of Marinesco-Sjögren syndrome.

The

    histochemical and immunocytochemical findings of biopsied muscle
    PARACLINICAL

 in a

    2-year-old
    AGE

    girl
    GENDER

 with

    Marinesco-Sjögren syndrome
    DIAGNOSIS

 are reported.

    Muscle histology
    PARACLINICAL

 consisted of

    mild muscular dystrophy
    DIAGNOSIS

    , such as that found in limb-girdle or non-Fukuyama congenital muscular dystrophy
    SYMPTOMS

. By

    immunocytochemical stain using anti-dystrophin antibody
    PARACLINICAL

,

    Duchenne and Becker muscular dystrophies were excluded
    NEG_FINDINGS

. In addition to characteristic clinical features, including

    ataxia
    SYMPTOMS

,

    congenital cataract
    SYMPTOMS

, and

    psychomotor retardation
    SYMPTOMS

,

    muscle involvement
    SYMPTOMS

 is essential to the diagnosis of

    Marinesco-Sjögren syndrome
    DIAGNOSIS

.

Marinesco-Sjögren syndrome
mild muscular dystrophy
Marinesco-Sjögren syndrome


A Japanese family with two types of muscular dystrophy: DNA analysis and the dystrophin test.

A unique Japanese family with both Fukuyama type congenital muscular dystrophy (FCMD) and Duchenne muscular dystrophy (DMD) is described. Four boys, all from the sixth generation of the same family, were afflicted with severe neuromuscular diseases beginning in early life, three of them presenting the typical phenotype of FCMD and one, that of DMD. Although DNA analysis by Southern blotting with complementary DNAs representing the whole of the dystrophin coding sequence detected neither gross deletions nor duplications, immunohistochemistry and Western blotting of the biopsied skeletal muscle with an antidystrophin monoclonal antibody (dystrophin test) showed that the approximately 400-kd dystrophin was expressed normally at the sarcoplasmic membrane of the FCMD phenotype patient but was completely absent in the DMD phenotype patient. From these results, it was presumed that two different childhood muscular dystrophies, FCMD and DMD, coexisted in this family. This unique case illustrates the efficacy of the dystrophin test in the differential diagnosis of the two diseases even when conventional means of diagnosis do not give definite answers and DNA analysis of the dystrophin gene is not informative.

A unique

    Japanese
    ETHNICITY

    family with both Fukuyama type congenital muscular dystrophy (FCMD) and Duchenne muscular dystrophy (DMD)
    FAMILY

 is described. Four

    boys
    GENDER

,

    all from the sixth generation of the same family
    FAMILY

, were afflicted with

    severe neuromuscular diseases
    DIAGNOSIS

 beginning

    in early life
    AGE

, three of them presenting the typical phenotype of

    FCMD
    DIAGNOSIS

 and one, that of

    DMD
    DIAGNOSIS

. Although

    DNA analysis by Southern blotting with complementary DNAs representing the whole of the dystrophin coding sequence
    PARACLINICAL

 detected

    neither gross deletions nor duplications
    NEG_FINDINGS

,

    immunohistochemistry and Western blotting of the biopsied skeletal muscle with an antidystrophin monoclonal antibody (dystrophin test)
    PARACLINICAL

 showed that

    the approximately 400-kd dystrophin was expressed normally at the sarcoplasmic membrane of the FCMD
    MICROSCOPIC

 phenotype patient but

    was completely absent in the DMD
    NEG_FINDINGS

 phenotype patient. From these results, it was presumed that two different

    childhood muscular dystrophies
    DIAGNOSIS

,

    FCMD
    DIAGNOSIS

 and

    DMD
    DIAGNOSIS

, coexisted in this family. This unique case illustrates the efficacy of the

    dystrophin test
    PARACLINICAL

 in the

    differential diagnosis
    PARACLINICAL

 of the two diseases even when conventional means of diagnosis do not give definite answers and

    DNA analysis of the dystrophin gene is not informative
    NEG_FINDINGS

.

severe neuromuscular diseases
FCMD
DMD
childhood muscular dystrophies
FCMD
DMD


[A two-year-old clinically manifesting carrier of Duchenne muscular dystrophy].

A two-year-old symptomatic carrier of Duchenne muscular dystrophy (DMD) confirmed by dystrophin immunohistochemical study was reported. She had mild proximal muscular weakness and elevated serum creatine kinase (CK) level. There were no family members of DMD. CT examination revealed low density areas in the muscles similar to that seen in the early stage of DMD. Biopsied specimen of muscle showed myopathic changes with necrotic and regenerating fibers. The immunohistochemical study using an antiserum against dystrophin showed the mosaic expression of the surface membrane, with positive and negative patches. Accordingly, she was strongly suggested to be a DMD carrier. This case shows that dystrophin immunohistochemistry is useful for diagnosis of a DMD carrier without affected family members.

A

    two-year-old
    AGE

 symptomatic carrier of

    Duchenne muscular dystrophy (DMD)
    DIAGNOSIS

 confirmed by

    dystrophin immunohistochemical study
    PARACLINICAL

 was reported.

    She
    GENDER

 had

    mild proximal muscular weakness
    SYMPTOMS

 and

    elevated serum creatine kinase (CK) level
    BIOCHEMICAL

. There were

    no family members of DMD
    FAMILY

.

    CT examination
    PARACLINICAL

 revealed

    low density areas in the muscles similar to that seen in the early stage of DMD
    SYMPTOMS

.

    Biopsied specimen of muscle
    PARACLINICAL

 showed

    myopathic changes with necrotic and regenerating fibers
    MICROSCOPIC

. The

    immunohistochemical study
    PARACLINICAL

 using an

    antiserum against dystrophin
    PARACLINICAL

 showed the

    mosaic expression of the surface membrane, with positive and negative patches
    MICROSCOPIC

. Accordingly,

    she
    GENDER

 was strongly suggested to be a

    DMD
    DIAGNOSIS

 carrier. This case shows that

    dystrophin immunohistochemistry
    PARACLINICAL

 is useful for diagnosis of a

    DMD
    DIAGNOSIS

 carrier

    without affected family members
    FAMILY

.

Duchenne muscular dystrophy (DMD)
DMD
DMD


Point mutation in the human dystrophin gene: identification through western blot analysis.

Using antibodies directed against the amino-terminus of dystrophin, we identified a truncated protein in a Duchenne muscular dystrophy patient. Antibodies directed against the carboxy-terminus failed to identify any cross-reactive material, a result consistent with premature termination of dystrophin translation. The estimated molecular mass of 126 kDa predicted the approximate location of the mutation in the mRNA and in the gene. Sequencing of cloned PCR products from patient muscle cDNA revealed a nonsense mutation, which was confirmed by direct sequencing of amplified patient genomic DNA. The mutation, a G to T transversion, at position 3714 changes a glutamic acid codon to an Amber stop codon. Translation of mRNA containing this mutation would be expected to result in a truncated protein with a molecular mass of 133 kDa, in close agreement with the 126 kDa estimated by Western blot analysis. This is the first reported case of a point mutation in this very large human gene.

Using antibodies directed against the amino-terminus of dystrophin, we identified a

    truncated protein
    BIOCHEMICAL

 in a

    Duchenne muscular dystrophy
    DIAGNOSIS

 patient.

    Antibodies directed against the carboxy-terminus failed to identify any cross-reactive material
    NEG_FINDINGS

, a result consistent with

    premature termination of dystrophin translation
    NEG_FINDINGS

. The estimated molecular mass of 126 kDa predicted the approximate location of

    the mutation in the mRNA and in the gene
    GENETICS

.

    Sequencing of cloned PCR products from patient muscle cDNA
    PARACLINICAL

 revealed a

    nonsense mutation
    GENETICS

, which was confirmed by

    direct sequencing of amplified patient genomic DNA
    PARACLINICAL

. The

    mutation, a G to T transversion, at position 3714 changes a glutamic acid codon to an Amber stop codon
    GENETICS

. Translation of mRNA containing this mutation would be expected to result in a truncated protein with a molecular mass of 133 kDa, in close agreement with the 126 kDa estimated by

    Western blot analysis
    PARACLINICAL

. This is the first reported case of a

    point mutation in this very large human gene
    GENETICS

.