While DNMT1, DNMT3a, and DNMT3b expression increased in leukocytes from PAH patients as compared to healthy controls, our data showing higher DNMT1 expression and PCWP in Caucasian than Hispanic/African American PAH patients suggests Caucasian patients with higher DNMT1 appear to have more severe PAH. The gene discussed is DNMT1; the disease is pulmonary arterial hypertension.