HDAC9 and scleroderma: 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.