We found that expression levels of DNA methyltransferase DNMT3A and histone deacetylases HDAC1/2/6/11 were significantly different between PAH and controls (all p < 0.05) and that there were significant correlations between the CpG markers and several of the epigenetic regulators (e.g. cg04917472 vs TET2 Rho = −0.29, p = 1.32 × 10−7, Supplementary Data 7). The gene discussed is HDAC1; the disease is pulmonary arterial hypertension.