TBX4 and pulmonary arterial hypertension: However, 17 other PAH-predisposing genes have recently been identified, including EIF2AK4, ACVRL1, TBX4, GDF2, SOX17, ENG, KCNK3, ABCC8, ATP13A3, SMAD9, AQP1, CAV1, BMP10, SMAD4, SMAD1, G6PD, and KDR [9,10,11].