Although ALS mostly affects patients without disease family histories, about 10% of ALS subjects show a familial form of this disease (fALS), mainly due to different gain-of-function mutations of SOD1 enzyme; indeed, the presence of a sporadic ALS (sALS), not clearly associated with SOD1 defects [27], has been described. The gene discussed is SOD1; the disease is amyotrophic lateral sclerosis.