In recent times, the CpG island on the BMPR2 promoter was found to be hypermethylated in scleroderma endothelial cells, whereas treatment with a DNMT inhibitor and/or HDAC inhibitor reversed the enhanced apoptosis of the cells, illuminating the possible contribution of abnormal DNA methylation in scleroderma pathogenesis.66 These epigenetic contributions might also have a relation to other cardiovascular disorders, including PAH, and should be addressed further in PAEC and PASMC beds, to reveal possible roles in PAH. Here, DNMT1 is linked to pulmonary arterial hypertension.