Splicing misregulation has been widely reported in noncoding repeat expansion diseases, such as in C9Orf72-FTD/ALS, in which RBP sequestration by RNA aggregates has been shown to be responsible for the formation of a variety of mRNA isoforms, completely changing the transcriptome in neuronal cells [144], while abnormal alternative polyadenylation has been reported for OPMD, in which the PAPBN1 mutation leads to 3′-UTR shortening, and for FXS, caused by a repeat expansion in FMR1 that affects the choice of polyA signals [145]. The gene discussed is FMR1; the disease is fragile X syndrome.