Furthermore, a small sample size in Caucasian and non‐Caucasian (Hispanic/African American) precludes us from affirmatively suggesting that differences in the epigenetics between the groups is a cause of the severity of PAH, the statistically significant differences between the groups certainly hints DNA methyltransferases and demethylases must be important to eliciting the severity of PAH in Caucasian group and this must be further studied. Here, MBD2 is linked to pulmonary arterial hypertension.