Angus cattle affected with pulmonary hypertension had a higher frequency of the endothelial PAS domain-containing protein 1 gene (EPAS1) encoding a hypoxia-inducible factor 2 alpha (HIF2α) double variant with threonine (T) at position 606 and serine (S) at 610. The gene discussed is EPAS1; the disease is pulmonary arterial hypertension.