Does Somatic Mosaicism Account For Some Sporadic Als?

Amyotrophic lateral sclerosis (ALS) is characterized by degeneration of motor neurons in the brain, brainstem, and spinal cord, resulting in muscle atrophy and weakness. Progression of the disease eventually leads to respiratory failure and death, usually within 3-5 years of symptom onset. Most ALS cases are sporadic, with approximately 5%-10% being familial.(1) To date, mutations in more than 120 genes have been shown to cause or increase the risk of ALS (), with mutations in about 20 genes being linked to monogenic forms of ALS. It is estimated that 40%-60% of individuals with familial ALS have an identified genetic mutation, depending on the population studied. The causes of the other familial ALS and more than 90% of sporadic ALS cases remain unknown.(2)