Hereditary hemorrhagic telangiectasia (HHT) is an inherited disorder of the blood vessels that can cause excessive bleeding.

HHT; Osler-Weber-Rendu syndrome; Osler-Weber-Rendu disease; Rendu-Osler-Weber syndrome

HHT is passed down through families in an autosomal dominant pattern. This means the abnormal gene is needed from only one parent in order to inherit the disease.

Scientists have identified four genes involved in this condition. All of these genes appear to be important for blood vessels to develop properly. A mutation in any one of these genes is responsible for HHT.

People with HHT can develop abnormal blood vessels in several areas of the body. These vessels are called arteriovenous malformations (AVMs).

If they are on the skin, they are called telangiectasias. The most common sites include the lips, tongue, ears, and fingers. The abnormal blood vessels can also develop in the brain, lungs, liver, intestines, or other areas.

Symptoms of this syndrome include:

• Frequent nosebleeds in children
• Bleeding in the gastrointestinal tract (GI), including loss of blood in the stool, or dark or black stools
• Seizures or unexplained, small strokes (from bleeding into the brain)
• Shortness of breath
• Enlarged liver
• Heart failure
• Anemia caused by low iron

Treatments may include:

• Surgery to treat bleeding in some areas
• Electrocautery (heating tissue with electricity) or laser surgery to treat frequent or heavy nosebleeds
• Endovascular embolization (injecting a substance through a thin tube) to treat abnormal blood vessels in the brain and other parts of the body

Some people respond to estrogen therapy, which can reduce bleeding episodes. Iron may also be given if there is a lot of blood loss, leading to anemia. Avoid taking blood-thinning medicines. Some drugs that affect blood vessel development are being studied as possible future treatments.

Some people may need to take antibiotics before having dental work or surgery. People with lung AVMs should avoid scuba diving to prevent decompression sickness (the bends). Ask your provider what other precautions you should take.

More information and support for people with HHT disorder and their families can be found at:

• Cure HHT -- curehht.org/
• National Organization for Rare Disorders -- rarediseases.org/rare-diseases/hereditary-hemorrhagic-telangiectasia/

People with this syndrome can live a completely normal lifespan, depending on where in the body the AVMs are located.

These complications can occur:

• Heart failure
• High blood pressure in the lungs (pulmonary hypertension)
• Internal bleeding
• Shortness of breath
• Stroke

Call your provider if you or your child has frequent nose bleeds or other signs of this disease.

Genetic counseling is recommended for couples who want to have children and who have a family history of HHT. If you have this condition, medical treatments can prevent certain types of strokes and heart failure.

Published Date: May 02, 2021
Published By: Anna C. Edens Hurst, MD, MS, Associate Professor in Medical Genetics, The University of Alabama at Birmingham, Birmingham, AL. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.

Centers for Disease Control and Prevention website. Blood disorders: facts about hereditary hemorrhagic telangiectasia (hht). www.cdc.gov/ncbddd/hht/. Updated October 27, 2020. Accessed June 11, 2021.

Cappell MS, Lebwohl O. Hereditary hemorrhagic telangiectasia. In: Lebwohl MG, Heymann WR, Berth-Jones J, Coulson IH, eds. Treatment of Skin Disease: Comprehensive Therapeutic Strategies. 5th ed. Philadelphia, PA: Elsevier; 2018:chap 102.

Kwah J, Brandt LJ. Vascular lesions of the gastrointestinal tract. In: Feldman M, Friedman LS, Brandt LJ, eds. Sleisenger and Fordtran's Gastrointestinal and Liver Disease. 11th ed. Philadelphia, PA: Elsevier; 2021:chap 38.

McDonald J, Pyeritz RE. Hereditary hemorrhagic telangiectasia. In: Adam MP, Ardinger HH, Pagon RA, et al, eds. GeneReviews [Internet]. Seattle, WA: University of Washington, Seattle; 1993-2021. www.ncbi.nlm.nih.gov/books/NBK1351/. Updated February 2, 2017. Accessed June 11, 2021.