Similar to C9ORF72-S, C9ORF72-AS also forms RNA foci in brain regions such as the frontal cortex and cerebellum, as well as the spinal cord (in MNs and occasionally in interneurons) of ALS [49, 163] and FTD patients [36, 49, 92]. This evidence concerns the gene C9orf72 and amyotrophic lateral sclerosis.