C9orf72 and Fuchs endothelial corneal dystrophy: Nuclear retention of introns has also been implicated in the pathogenesis of human hereditary disorders, including myotonic dystrophy type 2 (DM2, CNBP locus with CCTGexp), Fuchs endothelial corneal dystrophy (FECD, TCF4 locus with CTGexp), and amyotrophic lateral sclerosis/ frontotemporal dementia (C9-ALS/FTD, C9orf72 locus with GGGGCCexp) (Sznajder et al. 2018).