Hereditary Hemorrhagic Telangiectasia (HHT), called Osler-Weber-Rendu (OWR),  is a genetic disorder of the blood vessels which affects one in 5,000 people.

A person with HHT forms blood vessels that lack the capillaries that connect an artery and a vein. This type of abnormality involving small blood vessels is called telangiectasis (tel-AN-jee-eck-TAZE-ee-ya); the abnormality in large abnormal blood vessels is called arterioveneous malformation (AVM). The telangiectases and AVMs of HHT occur primarily in the nose, face, hands, mouth and the lining of the stomach and intestines, lungs and brain.

Telangiectases near the surface of skin and mucous membranes often rupture and bleed after slight trauma. The most common feature of this condition is spontaneous and recurrent nosebleeds, beginning around age 12.  About 25 percent of people with HHT have intestinal bleeding, which most commonly begins after age 50.  Symptoms are common in people who have large AVMs in the brain, lungs or gastrointestinal tract; complications from bleeding or shunting may be sudden and catastrophic.

The disorder is best managed through annual check-ups to monitor undiagnosed AVMs and treatment of complications.