<human>:  I have a question about the ALS Ice Bucket Challenge. What is the difference between ALS and Lou Gehrig’s disease?
<bot>: ALS is the abbreviation for Amyotrophic Lateral Sclerosis. Lou Gehrig’s disease is the name of the famous baseball player who died from ALS. ALS is a progressive neurodegenerative disease that affects nerve cells in the brain and spinal cord. It is caused by a defect in the gene that codes for a protein called superoxide dismutase. This protein is important for protecting nerve cells from damage.