C9orf72 and amyotrophic lateral sclerosis: Expanded pre/mRNA in repeat disorders were reported to form RNA foci and avidly bind/sequester splicing factors such as SRSF1 in SCA31/C9ORF72-related ALS [85,91,92], SRSF2 in SCA36/C9ORF72-related ALS [88,91,92] and MBNL1 in HD/SCA8 [46,96].