C9orf72 and frontotemporal dementia: For example, in C9orf72 amyotrophic lateral sclerosis and frontotemporal dementia (C9-ALS/FTD), the C9orf72 intron 1 GGGGCC expansion (GGGGCCexp) results in alternative first exon selection, intron 1 retention, altered sense and antisense transcription, sequestration of multiple repeat-binding proteins (e.g., HNRNPH1, RanGAP1) and RAN translation of dipeptide repeats (DPRs) [64].