Notably, demethylation in the promoters of key ALS-associated genes, including SOD1, FUS, TARDBP, and C9orf72, has been observed in both healthy and affected subjects (Coppedè et al., 2018), suggesting that major ALS causative genes undergo common epigenetic reprogramming. Here, C9orf72 is linked to amyotrophic lateral sclerosis.