Telangiectasia, hereditary hemorrhagic (HHT)

Telangiectasia, hereditary hemorrhagic (HHT): A genetic vascular disease with dilatation (widening) of capillaries and small arteries (arterioles) producing characteristic small red spots (called telangectases) in the skin and mucous membranes, particularly in the nose and gastrointestinal tract. These spots are fragile and bleed easily. Recurrent nosebleeds and chronic gastrointestinal bleeding are the usual major problems. Other organs may have the spots and bleed. HHT is an autosomal dominant disorder, meaning that the HHT gene is on a nonsex (autosomal) chromosome (in chromosome 9q34.1) and one copy of this gene is enough to cause the disease. HHT is also known as Osler-Rendu-Weber and Rendu- Osler-Weber disease or syndrome.