The following information may help to address your question:
What is hereditary hemorrhagic telangiectasia (HHT)?
Hereditary hemorrhagic telangiectasia
(HHT) is an inherited disorder of the blood vessels that can cause excessive bleeding. 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 parts of the body, such as the brain, lungs, liver, or intestines.
HHT is caused by mutations
in several genes
, including ACVRL1
, SMAD4, and GDF2
. At least 2 additional as-yet-unknown genes are also suspected.
It is inherited in an autosomal dominant
pattern, which means one copy of the altered gene in each cell is sufficient to cause the disorder.
There is no cure for HHT. Treatment is symptomatic and supportive, with a focus on controlling bleeding, either through surgery or medication.
Last updated: 4/20/2016
How might hereditary hemorrhagic telangiectasia (HHT) be treated?
Although there is not yet a way to prevent the telangiectases or AVMs associated with HHT, most can be treated once they occur. Management includes surveillance for undiagnosed AVMs and treatment for identified complications such as nosebleeds, gastrointestinal bleeding, anemia, pulmonary AVMs, cerebral AVMs, and hepatic AVMs.
Treatment of nosebleeds with humidification and nasal lubricants, laser ablation, septal dermoplasty, or estrogen-progesterone therapy can prevent anemia and allow individuals with HHT to pursue normal activities. In more severe cases, coagulation therapy may be needed.
Individuals with GI bleeding are treated with iron therapy to maintain hemoglobin concentration; endoscopic application of a heater probe, bicap, or laser; surgical removal of bleeding sites; and estrogen-progesterone therapy. Iron replacement and red blood cell transfusions are used to treat anemia.
Treatment of pulmonary AVMs is indicated for dyspnea, exercise intolerance, hypoxemia, and prevention of lung hemorrhage and the neurologic complications of brain abscess and stroke. Pulmonary AVMs with feeding vessels that exceed 1.0 mm in diameter require consideration of occlusion. Preventive measures should be undertaken by those who have pulmonary AVMs, including antibiotics prior to dental or surgical procedures, the implementation of IV filters, avoidance of blood thinners and non-steroidal anti-inflammatory medications, and regular monitoring by a qualified medical professional.
Cerebral AVMs greater than 1.0 cm in diameter are usually treated by surgery, embolotherapy, and/or stereotactic radiosurgery. Liver AVMs are currently treated only if a patient shows signs of heart failure or other significant health problems. Treatments might include liver transplantation or medications like bevacizumab.
Surveillance includes annual evaluations for anemia and neurologic conditions and re-evaluation for pulmonary AVMs every one to two years during childhood and every five years thereafter. Women with HHT considering pregnancy are screened and treated for pulmonary AVMs; if pulmonary AVMs are discovered during pregnancy, they are treated during the second trimester.
Last updated: 4/20/2016
What types of medical professionals can treat and provide ongoing care to individuals with hereditary hemorrhagic telangiectasia (HHT)?
The HHT Foundation recommends that people with HHT be assessed at least once at a specialized HHT Center. These centers facilitate the comprehensive coordination of care necessary for treating a patient who has HHT by proactively managing the care of patients with HHT. At these centers, a coordinated team of experts, knowledgeable about HHT, collectively cares for the patients seen at the Center. In most cases, a full-time nurse works closely with the specialists to care for the patient. Usually there is a coordinator on site to ensure proper follow up and coordination of patients care throughout the Center.
Each Center provides medical services that are currently being provided at that facility, but will provide these services in a more organized and consistent fashion. The patients have access to physicians who specialize in all aspects of HHT.
To locate an HHT Treatment Center near you, visit the following link:
If you are not able to get to a HHT Center, a genetics professional can help to coordinate your care. You may also benefit from seeing specialists in pulmonary medicine, gastroenterology, and an ears, nose and throat specialist (ENT). Other specialists may be appropriate, depending on your symptoms.
Last updated: 4/20/2016
How can I find a genetics professional in my area?
Last updated: 8/23/2016
We hope this information is helpful. We strongly recommend you discuss this information with your doctor. If you still have questions, please
GARD Information Specialist
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