Heterozygous mutations in the gene-encoding bonemorphogentic protein receptor type 2 (BMPR2) are the most common genetic causeof PAH, occurring in ∼15% of cases,185 and have been associated with worse RV function on cardiac MRI.305 Bi-allelic mutations in the eukaryotic translation initiation factor 2alpha 5 kinase 4 gene (EIF2AK4) are described in PVOD and PCH,306,307 whichare important to diagnose given their worse prognosis and poorer response to PAHtherapies. Here, EIF2AK4 is linked to pulmonary venoocclusive disease.