Facts at a Glance

General Information

1. Hereditary Hemorrhagic Telangiectasia (also known as Osler-Weber-Rendu Syndrome) is a multi-system vascular dysplasia.
2. Approximately 1.2 million people world-wide have HHT which is uncommon, but not rare.
3. Telangiectases and arteriovenous malformations (AVMs) are the characteristic lesions.
4. Symptoms can be mild to severe.
5. Physicians frequently miss (do not make) the diagnosis in affected individuals.
6. Most commonly affected organs are the nose, lungs, GI tract, brain, and spine-in that order.
7. HHT is an autosomal dominant genetic disorder. Denovo mutations are rare. A targeted family history shows almost all cases to be familial.
8. HHT is heterogenic with defects in at least 3 genes.
9. It is extremely rare for any one individual to have all the manifestations of HHT.
10. The severity of one's nosebleeds does not predict the likelihood to have internal (i.e. brain and lung) manifestations.
11. Severity of the disorder varies tremendously, even between close relatives.
12. Treatments are available for all manifestations of HHT.
13. Men and women are affected with HHT in equal numbers.
14. The HHT Foundation recommends that people with HHT be assessed at a specialized HHT Center at least once as early in life as possible. Diagnosis and treatment for HHT is complex and has changed significantly in the last decade.

HHT Manifestations

1. 90-95% of individuals with HHT will have nosebleeds by adulthood, but they vary from infrequent and minor to daily and severe.
2. 90-95% develop at least a few telangiectasia (small red or purple spots) on the skin of the face and/or hands by middle age.
3. 20-25% develop bleeding in the stomach or intestines, but rarely before 50 unless affected with juvenile polyposis in conjunction with HHT.
4. 30-50% have an arteriovenous malformation (AVM) in their lungs. These are usually present at birth and pose significant risk if not treated properly.
5. 5-20% have at least one AVM in their brain. These are present at birth and pose significant risk if not treated properly.
6. Hepatic AVMs are relatively common, approximately 5% are symptomatic.
7. Abnormal blood vessels in the liver are relatively common, but most cause no symptoms. Biopsy or treatment should rarely be done and specifically, embolization should not be done.

HHT Resources

• Patient Resources
• Physician Resources