While studies have associated EIF2AK4 genetic mutations with PVOD/PCH [139, 140, 141, 142, 143, 144, 145, 146, 147, 148], in a large cohort study, biallelic EIF2AK4 mutations were identified in patients clinically diagnosed with idiopathic and heritable PAH, suggesting a misclassification of some cases that resemble PVOD/PCH. The gene discussed is EIF2AK4; the disease is pulmonary venoocclusive disease.