Hereditary hemorrhagic telangiectasia (HHT) is a genetic disorder that affects about one in 5,000 people, or 1.4 million people worldwide. It causes abnormal connections between arteries and veins called vascular malformations that form throughout your body. These vascular malformations can increase your risk of bleeding, stroke, infections, and other complications.
At UPMC, our clinical goals include managing symptoms of HHT and preventing long-term complications, such as stroke and brain abscesses. We also focus on treating bleeding symptoms of HHT, which most often occur in the nose or gastrointestinal (GI) tract.
On this page:
What Is Hereditary Hemorrhagic Telangiectasia (HHT)?
Hereditary hemorrhagic telangiectasia (HHT) is a genetic disorder that affects about one in 5,000 people, or 1.4 million people worldwide. It causes abnormal connections between arteries and veins called vascular malformations that form throughout your body. These vascular malformations can increase your risk of bleeding, stroke, infections, and other complications.
What are the types of HHT?
Types of HHT include:
- Type 1 (HHT1) — Commonly causes pulmonary and cerebral arteriovenous malformations (AVMs), with symptoms appearing earlier in life.
- Type 2 (HHT2) — Commonly causes vascular malformations in the liver.
- JP-HHT — Causes HHT symptoms, as well as polyps in the gastrointestinal tract.
What is the difference between HHT type 1 and type 2?
HHT type 1 and type 2 affect different areas of the body. HHT type 1 typically causes AVMs in the lungs and brain, while HHT type 2 causes vascular malformations in the liver. Symptoms of HHT type 1 also tend to appear earlier in life.
How common is HHT?
HHT is a rare disease that affects about one in 5,000 people, or 1.4 million people worldwide.
What causes HHT?
HHT is a genetic condition that is passed from biological parent to child and is present at birth. Gene mutations (changes) cause abnormal connections between arteries and veins to develop throughout the body.
These abnormal connections can lead to:
- Telangiectasias — Malformations of small blood vessels in the skin, nose, stomach, and intestines.
- Arteriovenous malformations (AVMs) — Abnormal connections in larger arteries or veins in the brain, spinal cord, lung, and liver.
Genetic causes of HHT
People with HHT inherit it in an autosomal dominant fashion. This means that you only need one parent to carry the mutated gene to develop HHT. The abnormal or mutated gene produces a protein that leads to abnormal blood vessel development.
Most often, people with HHT have a mutation in one of three genes:
- Endoglin (ENG), which causes HHT1.
- Activin receptor type II-like kinase 1 (ACVRL1), which causes HHT2.
- SMAD4, which causes a combined syndrome of juvenile polyposis (multiple polyps in the intestine) and HHT, known as JP-HHT.
Your first-degree relatives (biological parents, brothers and sisters, and children) have a 50% chance of having the disease if you have the disease, regardless of whether they are symptomatic.
It's rare — but not impossible — to develop HHT even if one of your parents does not have the disease.
HHT risk factors
HHT is a genetic condition that is passed from biological parent to child and is present at birth. If you have a parent or another relative with HHT, you have a higher risk of developing the condition.
Complications of HHT
Complications of HHT may include:
- Stroke — Ruptured brain AVMs may result in hemorrhagic (bleeding) stroke. Lung AVMs can result in embolic stroke. This happens when a blood clot, which the small lung capillaries would usually trap, passes into the lung veins through an AVM and lodges in and blocks small vessels in your brain.
- Brain abscess — Occurs when bacteria, which the lung capillaries normally filter out of circulation, pass through lung AVMs and into your brain, causing an infection.
- Heart failure — This is a possible long-term effect of liver AVMs.
Is HHT serious?
Without treatment and follow-up care, HHT can lead to serious complications, such as stroke, bleeding, infection, and heart failure. However, most people's symptoms can be managed with ongoing treatment and follow-up care.
How can I prevent HHT?
HHT is a genetic condition, so there's nothing you can do to prevent it.
However, if you have a family member with HHT, you should consider diagnostic or genetic testing. Early diagnosis, follow-up care, and long-term monitoring can help reduce the risk of complications from HHT.
What Are the Signs and Symptoms of HHT?
HHT may cause different symptoms in different families, and even in different people within the same family.
The most common HHT symptoms include:
- Nosebleeds — More than 90% of people with HHT have recurrent nosebleeds ranging from mild to severe. Nosebleeds occur when nasal telangiectasias rupture.
- Visible telangiectasias — These often occur on the fingertips, lips, and tongue. They look like small red dots. When you pressure them, they turn white because pressure prevents the high-flow blood from moving through the malformation.
Some rare but serious symptoms of HHT include:
- Fatigue and shortness of breath —Some people with HHT may experience these symptoms because of anemia due to blood loss from nasal and/or gastrointestinal telangiectasias. The presence of lung AVMs can also cause fatigue and shortness of breath.
- Blood in stool — Ruptured telangiectasias in the stomach and intestines can cause blood in your stool.
- Anemia — Anemia is a common complication of HHT, resulting from nosebleeds and gastrointestinal bleeding. Your doctor will typically start with iron supplementation (oral or intravenous) to manage blood-loss anemia. In more severe cases, a transfusion may be necessary.
What is the age of onset for HHT?
The age at which people begin having HHT symptoms varies. Most experience some symptoms by the age of 20, and almost all affected individuals will have some signs or symptoms by age 50.
When should I see a doctor about my HHT symptoms?
If you have a biological parent or another relative who has been diagnosed with HHT or if you have symptoms, you should see a doctor right away for testing. If you are having severe symptoms such as uncontrollable bleeding or signs of stroke, you should dial 911.
How Do You Diagnose HHT?
Your doctor will review your family history and symptoms before performing a physical exam and ordering tests to help diagnose your condition.
What to expect during your visit
At your first visit, your doctor may not know if you have internal AVMs. If your doctor suspects HHT, he or she will:
- Ask about your symptoms.
- Perform a physical exam.
- Order other tests.
- Review your health history and medications.
Tests to diagnose HHT
Your doctor may perform or order tests to diagnose HHT, including:
Curaçao criteria
UPMC doctors use the “curaçao criteria” to diagnose HHT.
The four criteria include:
- Recurrent nosebleeds, also known as epistaxis.
- Telangiectasias, mainly on the hands, face, and in the mouth.
- Arteriovenous malformations (AVMs) in major organs, such as the liver, lung, or brain.
- A family history of HHT.
If you meet 0-1 criteria, you are unlikely to have HHT.
If you meet 2-3 criteria, there is a chance that you have HHT.
If you meet 3-4 criteria, you are highly likely to have HHT.
Noninvasive diagnostic tests
Imaging tests for HHT include:
- CT scan — A test that creates images of your body's organs, bones, and tissues.
- Echocardiogram (ECHO) — A noninvasive test that uses sound waves to create images of your heart, which can help to identify abnormalities.
- MRI — Uses a combination of large magnets, radio frequencies, and a computer to produce detailed images of your organs and tissues.
Genetic tests
Your doctor may suggest genetic testing to find out if you have a gene mutation that causes HHT, including:
- Activin receptor type II-like kinase 1 (ACVRL1).
- Endoglin (ENG).
- SMAD4.
HHT prognosis
Early diagnosis and treatment can reduce your risk of complications from HHT.
What is the life expectancy of someone with HHT?
If left untreated, HHT can increase your risk of a life-threatening stroke and bleeding. However, with ongoing treatment and follow-up care, most people with HHT can live a normal life with a normal life expectancy.
How Do You Treat HHT?
The goals of HHT treatment are to manage the current symptoms of HHT and prevent long-term complications, including stroke and brain abscesses.
Treatment for HHT depends on what areas of your body are affected and may include:
Preventive screening and treatment for HHT
Screening for lung and brain vascular malformations is the most important step in preventing neurological problems. Preventive screening tests include:
- An echocardiogram (ultrasound) of your heart.
- An MRI of your brain.
Treatments to control nosebleeds
Nasal bleeding and internal bleeding from the GI tract are the most common causes of chronic HHT symptoms. Your doctor may recommend keeping your nose moisturized to prevent dryness that may lead to bleeding.
If this is not effective, our ENT specialists can destroy the vascular malformations with laser surgery. After laser surgery, the surgeons may inject a drug called bevacizumab (Avastin®) into the malformations to prevent the growth of new vessels.
Treatments to control gastrointestinal (GI) bleeding
We treat bleeding from vascular malformations in the GI tract by destroying the bleeding vessels during endoscopy and colonoscopy procedures. Your doctor will use a flexible tube with a light and camera on the end to look for and destroy vascular malformations in your digestive tract.
Treatment for lung vascular malformations
If you have lung vascular malformations, you may be referred to a specialist called an interventional radiologist for treatment. Lung vascular malformations are treated by blocking them off with coils during a procedure called embolization. This prevents blood clots and bacteria from passing through and causing strokes and brain abscesses.
Treatment for brain vascular malformations
Treatment of brain vascular malformations may include:
- Neurosurgery to repair or remove the vascular malformation.
- Occlusion (blocking) with coils, which is performed during a minimally invasive procedure.
- Radiosurgery, which uses precisely focused radiation beams to treat AVMs.
Treatment of liver complications
Vascular malformations can affect your liver. These require treatment only if they cause severe liver problems or heart failure. A liver transplant may be the best treatment option in these cases.
Why Choose UPMC for HHT Care?
When you choose UPMC for HHT care, you will receive:
- Access to world-class HHT expertise — Our world-renowned experts specialize in diagnosing HHT and will develop a comprehensive treatment plan to manage all related symptoms and complications.
- A full range of treatment options — We offer nonsurgical care, as well as minimally invasive and traditional open surgical procedures, allowing us to effectively treat HHT while reducing your risk of serious complications.
- Multidisciplinary care — We partner with ENT, neurosurgery, pulmonary, and gastrointestinal specialists, as well as other medical experts, to provide complete care that improves your quality of life.
