Hereditary hemorrhagic telangiectasia (tuh-lan-jee-uk-TAY-zhuh) is a disorder that affects blood vessels. It can cause bleeding in the digestive tract, anemia, increased risk of stroke and other symptoms. In most cases, hereditary hemorrhagic telangiectasis (HHT) isn't life-threatening and symptoms can be effectively managed.

With HHT, also known as Osler-Weber-Rendu disease, some of the networks of blood vessels that join arteries to veins (capillaries) aren't correctly formed. In small blood vessels, these abnormalities are called telangiectases. When they occur in larger vessels, they're called arteriovenous malformations (AVMs). People who have HHT may have both kinds of malformations.

HHT is genetic and can affect people at any age. Its severity can vary greatly from person to person, even within the same family.

HHT care at Mayo Clinic