TGFB1 and idiopathic pulmonary arterial hypertension: Several authors hypothesized a central role of TGF-β signaling pathway components known to be involved in HHT gene mutations (ENG, ACVRL 1) and implicated in the pathophysiology of atherosclerosis, and other hereditary diseases like primary pulmonary hypertension and aortic aneurysm syndromes (Marfan, type IV Ehlers-Danlos and Loeys-Dietz syndromes) [20,28].