C9orf72 and amyotrophic lateral sclerosis: Cumulative incidence of ALS and dementia in individuals carrying more than 30 repeats in C9orf72 was 58% (50%–65%) at age 80 compared to 5.8% (4.6%–7.0%) in controls (Plog-rank < 0.001) (Supplementary Table 7 and Supplementary Fig. 7), assuming survival to this age.