ATRX and deafness: In addition to the ATR-X epi-signature described here, our group has recently demonstrated unique DNA methylation signatures in patients with two other conditions, including Floating–Harbor syndrome, which is caused by mutation in the SRCAP gene, as well as cerebellar ataxia, deafness and narcolepsy syndrome, which is caused by mutations in the DNMT1 gene [44, 45].