SMAD1 and pulmonary arterial hypertension: The other previously identified PAH‐associated genes: ACVRL1, BMPR1B, CAV1, KCNA5, KCNK3, SMAD1, SMAD4, SMAD9, TBX4, TOPBP1, ENG, GDF2, and EIF2AK4 included 45 (missense=40 and nonsense=5) of the 180 missense/nonsense PAH‐associated variants (Table 1).