More importantly, the analysis of differential methylated m6A sites in this study showed that multiple genes related to PAH, including ACVRL1, ENG, SMAD6 and SMAD9, had down-regulated methylation, and those genes have been found related to TGF-β signal pathway in molecular function, biological process or KEGG pathway. The gene discussed is SMAD6; the disease is pulmonary arterial hypertension.