An illustrative example is that of myelin genes, such as myelin oligodendrocyte glycoprotein (MOG), 2′,3′‐cyclic nucleotide 3′ phosphodiesterase (CNP), proteolipid protein 1 (PLP1), myelin basic protein (MBP), myelin‐associated oligodendrocyte basic protein (MOBP) or myelin associated glycoprotein (MAG), which were hypomethylated in OLs and were found to be hypermethylated in X‐ALD, both in the childhood and adult phenotypes (Supporting Information Table S5). The gene discussed is PLP1; the disease is adrenoleukodystrophy.