GDF2 and pulmonary arterial hypertension: Heterozygous germ‐line BMP9 (GDF2) missense, truncating, and deletion mutations have been reported in patients with PAH on four separate occasions, bringing the total number of reported cases to 32 (Eyries et al., 2019; Gräf et al., 2018; Wang et al., 2016; Wang et al., 2019).