American Angus cattle affected with pulmonary hypertension at altitudes of 1,478 to 2,618 m had a higher frequency of the endothelial PAS domain-containing protein 1 gene (EPAS1) encoding a hypoxia-inducible factor 2 alpha (HIF2α) missense variant. This evidence concerns the gene EPAS1 and pulmonary arterial hypertension.