In PAH, DNA methylation mediates CpG site methylation in gene promoters and enhancer regions via DNA methyltransferases (DNMTs), leading to hypermethylation or hypomethylation of immune-metabolic related genes such as EIF2AK4, TCF7, and SOCS3 with concomitant abnormal expression, which enriches functions like T cell differentiation and participates in the pathological process of PAH (Benincasa et al., 2023; Hindmarch et al., 2025). The gene discussed is TCF7; the disease is pulmonary arterial hypertension.