Nine expansion disorders have been added since the first discovery of RAN translation in SCA8 and DM1: C9orf72 amyotrophic lateral sclerosis/frontotemporal dementia [20,21,22], fragile X tremor/ataxia syndrome [23], Huntington’s disease (HD) [24,25], spinocerebellar ataxia 3 and 31 [26,27], Fuchs’ endothelial corneal dystrophy [28] and myotonic dystrophy type 2 (DM2) [29]. The gene discussed is RAN; the disease is juvenile Huntington disease.