In the C9orf72 group, 10 out of 66 rated patients (15.2%), were consistent with diagnosis of FTD in neuropsychological examination which was higher compared to sporadic amyotrophic lateral sclerosis (18/304 (5.9%); P = 0.02) and SOD1 (0/11 (0%), P = 0.34). Here, SOD1 is linked to amyotrophic lateral sclerosis.