Also, since C9orf72-associated amyotrophic lateral sclerosis generally affects older patients if compared to SOD1, and due to the steadily increasing life expectancy, it is possible that ancestors of actual C9orf72 patients may not have reached the respective age to develop clinical signs of amyotrophic lateral sclerosis. This evidence concerns the gene C9orf72 and amyotrophic lateral sclerosis.