The relevance of endoglin in the cardiovascular system is reflected by the fact that mutations in the endoglin gene cause a vascular disease called the Rendu-Osler-Weber syndrome or HHT1 [11], which is characterized by vascular dysplasia, frequent episodes of epistaxis, mucocutaneous telangiectases and arteriovenous malformations of the lung, brain, liver and gastrointestinal tract [43]. The gene discussed is ENG; the disease is telangiectasia, hereditary hemorrhagic, type 1.