Hereditary Hemorrhagic Telangiectasia

Abstract Hereditary hemorrhagic telangiectasia is an autosomal dominant disease of blood vessels, affecting approximately 1 in 8000 individuals. It is characterized by mucocutaneous telangiectases, recurrent epistaxes, gastrointestinal bleeding, and arteriovenous malformations in the lungs, brain, and liver. Hereditary hemorrhagic telangiectasia can be caused by mutations in either the endoglin gene or theALK1gene, both of which encode proteins involved in serine‐threonine kinase signaling in the endothelial cell. These genes are thought to account for the majority of cases. Currently, the diagnosis is made using published clinical diagnostic criteria. Affected younger adults may be presymptomatic, so mutation analysis, where available, is an important adjunct to clinical diagnosis.