Dr. Pyeritz focuses his research in two areas: Mendelian disorders of the cardiovascular system, especially those involving defects of connective tissue, and ethical, legal and social implications of human genetics. He is continuing his studies, begun over 20 years ago, of Marfan syndrome and related conditions, diseases in which the aorta and occasionally major arterial branches, gradually enlarge and dissect, leading to early demise if untreated. Current efforts include the identification of additional genes that predispose to arteriopathy, and improving methods for diagnosis and treating arterio-venous malformations, especially in hereditary hemorrhagic telangiectasia (HHT).