C9orf72 and amyotrophic lateral sclerosis: The reduced C9orf72 mRNA in the frontal cortices and cerebella of c9FTD/ALS patients is associated with increased binding of C9orf72 to H3K9me3, H3K27me3, and H4K20me3 marks [160], associated with heterochromatin and transcriptional repression [27].