Two more separate identities in PAH WHO Group 1 are pulmonary veno-occlusive disease (PVOD), which can be heritable (eukaryotic translation initiation factor 2α kinase EIF2AK4 mutation), associated with autoimmune diseases or idiopathic, and persistent pulmonary hypertension of the newborn (PPHN). The gene discussed is EIF2AK4; the disease is pulmonary venoocclusive disease.