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]. This evidence concerns the gene TGFB1 and pulmonary arterial hypertension.