C9orf72 and fragile X-associated tremor/ataxia syndrome: Distinct repeat motifs and/or lengths have been associated with the same MoA in other pathologies, like CGG in fragile-X-associated tremor/ataxia syndrome (FXTAS), CCTG in myotonic dystrophy type 2 (DM2), TGGAA in SCA31, and recently, a complex repeat motif, GGGGCC, (G4C2) hexanucleotide repeat in the chromosome 9 ORF 72 (c9orf72) gene as the most common genetic cause of amyotrophic lateral sclerosis (ALS) with frontotemporal dementia (C9-ALS/FTD) [64,65,66,67].