Our study (Figure 2) reported gene ontologies, including ‘positive regulation if BMP signaling pathway’ and ‘negative regulation of TGF-β signaling pathway,’ which confirmed the imbalance between the ALK5-Smad2/3 pathway and ALK1-Smad1/5/8 pathways in in these gene mutations, resulting in PAH. This evidence concerns the gene SMAD2 and pulmonary arterial hypertension.