In C9ORF72 familial cases of ALS, there is also an increase in chromatin suppressive marks such as trimethylation at residues H3K9, H3K27, H3K79 and H4K20 (Belzil et al., 2013) and a TAD boundary is located at the C9ORF72 locus (Sun et al., 2018). Here, C9orf72 is linked to amyotrophic lateral sclerosis.