Hereditary Haemorrhagic Telangiectasia

Also known as: Osler-Rendu-Weber; Rendu-Osler-Weber


Hereditary haemorrhagic telangiectasia (HHT) is a genetic disorder that leads to the development of abnormally wide and fragile blood vessels.


Medical text written May 2001 by Dr C Shovlin, Senior Lecturer and Honorary Consultant Respiratory Physician, Respiratory Medicine Unit, Hammersmith Hospital, London, UK. Last updated November 2005 by Dr M Porteous, Consultant Clinical Geneticist and Reader in Clinical Genetics, Western General Hospital, Edinburgh, UK.

What are the symptoms?

Most people affected by HHT experience two problems:

  • the fragile blood vessels are prone to bleed, for example, in the nose causing nose bleeds, and less frequently in the gut. Generally, this bleeding settles down on its own, but if it leads to anaemia, it may need treatment with iron tablets, or with a blood transfusion if severe
  • the abnormal blood vessels may become visible as blood spots, for example on the lips or fingertips.

A few people will have abnormal vessels elsewhere. The lungs are affected in 1 in 5 individuals with HHT and it is important that this is recognised (see below). For other sites, such as the liver and brain, it is not clear that any specific tests or treatment are needed if they are not causing problems already.

About 1 in 5 individuals with HHT develops abnormal vessels in the lungs. These are called pulmonary arteriovenous malformations (PAVMs). These malformations let blood bypass or ‘shunt’ past the lung airsacs. They are particularly important because individuals who have PAVMs are at risk of having a ministroke or brain abscess even if they feel well. In addition, a few women with PAVMs have complications during pregnancy. It is therefore important to check whether or not PAVMs are present and, if so, arrange for a simple treatment to close them off.

Inheritance patterns and prenatal diagnosis

Inheritance patterns
Autosomal dominant. The earliest sign of HHT in children is usually nose bleeds, but nose bleeds may not develop until middle age. Because HHT may not become apparent until late in life, we are unable to say that younger members of a family are definitely unaffected. It is sensible for their medical records to include the fact that they have a parent with HHT, and for them to be screened for lung involvement.

Prenatal diagnosis 
This is possible in families where a genetic change has been identified.

Is there support?

Telangiectasia Self Help Group

Tel: 01494 528 047

The Group was established in 1985. It offers contact with others affected by the condition where possible. The Group has over 600 members, publishes a periodic newsletter and has information available.

Group details last updated September 2014.

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