Compared to matched controls, C9orf72 HRE carriers had a higher cumulative incidence by age 80 of ALS [21% (95% CI 16%–27%) versus 0.4% (0.1%–0.7%), Plog-rank < 0.001], FTD [10% (5.4%–15%) versus < 0.1% (0%–0.2%), Plog-rank <0.001] and any-cause dementia [59% (49%–67%) versus 5.4% (4.1%–6.7%), Plog-rank <0.001] (Table 1 and Fig. 1). This evidence concerns the gene C9orf72 and frontotemporal dementia.