Osler-Weber-Rendu syndrome is an inherited disorder of the blood vessels that can cause excessive bleeding.

Hereditary hemorrhagic telangiectasia; HHT

Osler-Weber-Rendu syndrome is an inherited condition. It can affect males or females of any ethnic or racial group.

People with this condition can develop abnormal blood vessels called arteriovenous malformations (AVMs) in several areas of the body. If they are on the skin, they are called telangiectasias. The AVMs can also develop in other areas of the body, such as the brain, lungs, liver, or intestines.

The syndrome is genetic, which means it results from an abnormality in one of a few genes. Scientists have identified some of the genes involved. However, they do not know exactly how the gene defects lead to the abnormal blood vessels seen in persons with this syndrome.

• Frequent nosebleeds in children
• GI bleeding, including loss of blood in the stool or dark black stools
• Port wine stain
• Seizures or unexplained, small strokes (from bleeding into the brain)
• Shortness of breath
• Telangiectases on the tongue, lips, nasal mucosa, face, ears, fingertips, nails, whites of the eyes, and skin (they may bleed easily)

An experienced health care provider can detect telangiectases during a physical examination. There is often a family history of hereditary hemorrhagic telangiectasia.

Signs include:

• Abnormal blood vessels that bleed easily in the throat, bowels, or airways
• AVM seen on chest x-ray
• Decreased oxygen levels in the blood
• Heart failure
• Hepatomegaly
• Iron deficiency anemia

Tests include:

• Blood gas tests
• Blood tests
• Echocardiogram
• Endoscopy

Genetic testing may be available for changes (mutations) in the endoglin or ALK1 genes.

Treatments include:

• Surgery to treat bleeding in some areas
• Electrocautery or laser surgery to treat frequent or heavy nosebleeds
• Endovascular embolization to treat abnormal blood vessels in the brain and other parts of the body

Some patients respond to estrogen therapy, which can reduce bleeding episodes. Avoid taking blood-thinning medications.

Some patients may need to take antibiotics before having dental work or surgery. Ask your doctor what precautions you should take.

HHT Foundation International -- www.hht.org

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

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

Call your health care provider if 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 hereditary hemorrhagic telangiectasia. Medical treatments can prevent certain types of strokes and heart failure.

Azuma H: Genetic and molecular pathogenesis of hereditary hemorrhagic telangiectasia. J Med Invest. 2000 Aug; 47(3-4): 81-90.

Faughnan ME, Hyland RH, Nanthakumar K, Redelmeier DA: Screening in hereditary hemorrhagic telangiectasia patients. Chest. 2000 Aug; 118(2): 566-7.

Govani FS, Shovlin CL. Hereditary haemorrhagic telangiectasia: a clinical and scientific review. Eur J Hum Genet. 2009 Apr 1. [Epub ahead of print]