Mutations in the human ENDOGLIN gene (ENG) are responsible for Hereditary Hemorrhagic Telangiectasia (HHT) type 1, a disease characterized by frequent nose bleeds, telangiectases on skin and mucosa and arteriovenous malformations in lung, liver and brain [4], [5], [6]. The gene discussed is ENG; the disease is arteriovenous hemangioma/malformation.