C9orf72 and frontotemporal dementia: Characteristically, pedigrees in which the mutated allele of C9orf72 segregated from one generation to another, showed different affected phenotypes, ranging from amyotrophic lateral sclerosis (ALS) to frontotemporal dementia (FTD) sometimes with peculiar features (DeJesus-Hernandez et al., 2011; Renton et al., 2011).