C9orf72 and fragile X-associated tremor/ataxia syndrome: When repeat expansions are located in non-coding regions, diseases such as myotonic dystrophy types 1 and 2 (DM1/2), C9orf72-amyotrophic lateral sclerosis/frontotemporal dementia (C9orf72-ALS/FTD), fragile-X tremor ataxia syndrome (FXTAS), spinocerebellar ataxias types 8, 10, 12, 31, and 36 (SCA 8/10/12/31/36), Huntington’s disease-like 2 (HDL2), and Fuch’s endothelial corneal dystrophy (FECD) occur (Mohan et al., 2014; Rohilla and Gagnon, 2017; Zhang and Ashizawa, 2017).