The second group, ‘Aged SOD1′ were SOD1 mice at the age of 5–7 months, which showed symptoms of ALS (Symptomatic group, n = 55), including rigid paralysis and minimal joint movement of the limbs, corresponding to neurological score (NS) 2 as described by refs. 12,13. This evidence concerns the gene SOD1 and amyotrophic lateral sclerosis.