C9orf72 and spinocerebellar ataxia type 8: The accumulation of RAN proteins has been found in the disease-relevant tissue of a growing number of repeat expansion disorders, including spinocerebellar ataxia type 8 (SCA8), Huntington’s disease (HD), C9orf72 ALS/FTD, and myotonic dystrophy type 1 and type 2.