ACVRL1 and hereditary hemorrhagic telangiectasia: That is, hereditary hemorrhagic telangiectasia (or HHT) caused by mutations in ACVRL1 and ENG, involves arteriovenous malformations mainly affecting the lungs and liver; or, mutations in BMPR2 may lead to pulmonary hypertension with no impairment of the endothelium in other organs [143].