Mutations in ENG and ACVRL1 genes disrupt TGF-β signalling, altering EC tubulogenesis and pericyte recruitment causing abnormal capillary formation and maturation leading to venous enlargement, vascular hyperbranching, and arteriovenous malformations explaining the abnormal morphogenesis of vasculature in HHT [24,31]. Here, ENG is linked to hereditary hemorrhagic telangiectasia.