Hereditary Hemorrhagic Telangiectasia (Osler-Weber-Rendu Syndrome)

Hereditary hemorrhagic telangiectasia (Osler-Weber-Rendu syndrome) is a rare genetic disorder that affects the blood vessels in the body.

In a normal circulatory system, the blood moves at high pressure through the larger blood vessels (arteries) into smaller vessels (arterioles and capillaries) before finally making its way into the small veins. The high pressure allows the blood to reach the veins, but in a healthy system, the pressure is much lower by the time the blood gets there.

Hereditary hemorrhagic telangiectasia occurs when the arteries are directly connected to the veins, meaning that blood flows at high pressure into the veins, which are less flexible than the other blood vessels. This can result in the veins bursting (hemorrhage). When this happens near the surface of the skin, small red marks (telangiectases) appear on the skin.

There are four types of hereditary hemorrhagic telangiectasia that are classified based on the area of the body affected and the genes involved. These are:

  • Type 1 — symptoms occur earlier in life and are more likely to involve the blood vessels of the brain and lungs
  • Type 2 and Type 3 — more likely to involve the blood vessels of the liver
  • Juvenile polyposis/hereditary hemorrhagic telangiectasia syndrome — associated with abnormal blood vessel development and the development of growths called polyps in the digestive tract


Symptoms of hereditary hemorrhagic telangiectasia vary depending on the severity of the condition and the location of the affected blood vessels. Red lines or patterns on the skin (telangiectasia) and nosebleeds are the most common symptoms. The bleeding associated with the condition usually becomes more severe as the patient ages.

When the blood vessels of the brain are affected, the patient may experience a stroke. If you notice one or more of these signs in another person or in yourself, do not wait to seek help. Call 9-1-1 immediately.

The signs of a stroke are:

  • Sudden numbness or weakness of the face, arm or leg, especially on one side of the body
  • Sudden confusion
  • Sudden trouble speaking
  • Sudden trouble seeing in one or both eyes
  • Sudden trouble walking
  • Sudden dizziness, loss of balance or coordination
  • Sudden, severe headache with no known cause

If the digestive tract is affected, the disease is usually not detected until the patient is in their 40s. Symptoms associated with the condition in the digestive tract often go unnoticed, but in rare cases, patients may experience blood in the stool or vomit.

Due to repeated blood loss, patients with the condition also tend to have a shortage of red blood cells (anemia), which can cause fatigue, weakness and pale skin.


Causes and Risk Factors

Hereditary hemorrhagic telangiectasia is a type of arteriovenous malformation (AVM) caused by a change in the genes known as ACVRL1, ENG and SMAD4. The condition is inherited, and the patient needs to have only one copy of the abnormal gene from one parent in order to develop it.

The condition is underdiagnosed, because some individuals have mild or no symptoms. Hereditary hemorrhagic telangiectasia is diagnosed in 1 out of every 5,000 people. The condition affects men and women equally and can be diagnosed at any age.


Diagnosis of hereditary hemorrhagic telangiectasia usually begins with a physical exam and a review of the patient's medical history and symptoms. A positive diagnosis is based on identifying at least three of the four main criteria, as well as the findings of imaging tests. The four main criteria are:

  • Repeated nosebleeds
  • Multiple telangiectases in characteristic locations
  • Internal (visceral) telangiectases or arteriovenous malformations
  • A family history of the condition

Imaging tests, such as magnetic resonance imaging (MRI) and computed tomography (CT), are used to look at the cerebrovascular system (the blood vessels in the brain) and gastrointestinal system (the stomach and intestines). An MRI or CT scan also may be used to look for areas of that may have been damaged by a stroke.


There is no cure for hereditary hemorrhagic telangiectasia. Treatment for the condition generally is focused on managing the symptoms.

Nosebleeds are managed through the use of humidifiers, nasal lubrication or applying pressure to the affected area. Severe cases may require surgery to stop the bleeding.

If the gastrointestinal tract is affected by the condition, iron replacement therapy is used as treatment. Other medicines may be prescribed for the condition, and endoscopic ablation (removal of diseased tissue) may also be used. Some patients with severe cases of anemia may need a blood transfusion. When the condition affects blood vessels in the brain, treatment may include surgery, intentional blockage of an artery (embolotherapy) and stereotactic radiosurgery.

For patients who have experienced a stroke, the Stroke Program at Cedars-Sinai provides a multidisciplinary treatment approach through a treatment plan tailored to each patient. Patient care is generally broken down into three categories: stroke prevention, treatment immediately after a stroke and post-stroke rehabilitation.

For patients with a hereditary condition, genetic counseling, available through the Cedars-Sinai Medical Genetics Institute, can help identify families at risk and provide referrals to specialized health care providers.