Telangiectasia, hereditary hemorrhagic

A genetic disease characterized by the presence of multiple direct connections between arteries and veins called arteriovenous malformations (AVMs). The small AVMs close to the surface of skin and mucous membranes (as in the mouth) are the telangiectases that often rupture and bleed after even slight trauma. The recurrent nosebleeds begin at about 12 years of age. About a quarter of patients with hereditary hemorrhagic telangiectasia (HHT) have gastrointestinal bleeding, usually after age 50. It can be life-threatening. Large AVMs may also bleed in the brain, lung, or other sites and pose major problems. HHT is inherited as an autosomal dominant trait. Most patients have a parent with HHT. Each child of a person with HHT has a 50 percent risk of inheriting the condition. HHT is unusual in that it can be caused by a mutation in one of two different genes: the endoglin gene on chromosome 9 or the activin receptor gene on chromosome 12. HHT is also known as Osler-Rendu-Weber and Rendu- Osler-Weber disease or syndrome. Although his name was never given to the disorder, it was first described in 1865 by the British physician Benjamin Guy Babbington (who also invented the laryngoscope).