HHT: What is Hereditary Hemorrhagic Telangiectasia?

Hereditary Hemorrhagic Telangiectasia (HHT) is a genetic disorder of the blood vessels that results from a missing or broken gene. This causes the development of multiple abnormalities in the blood vessels. HHT was first described as a hereditary disorder in 1896 by Dr. Rendu.

There are four different types of the disorder. Those with Type 1 may develop symptoms earlier. Type 2 patients have a higher risk of liver involvement. The fourth type is called Juvenile Polyposis/Hereditary Hemorrhagic Telangiectasia syndrome.

Children with HHT form blood vessels that lack the capillaries between an artery and vein. Capillaries are small blood vessels where the arteries drop off oxygen and then flow into the veins. When the capillaries are not there the arterial blood flows directly into the vein at full force and the pressure can rupture the vessels and result in bleeding.

The symptoms of HHT include frequent nosebleeds and telangiectases (red-violet spots) that may bleed easily and may be seen on the tongue, lips, nasal mucosa, face, ears, fingertips, nails, whites of eyes and skin. In HHT the spots occur because the blood vessel is fragile and bleeds easily. Lesions can occur in the digestive tract and there is also a possibility for GI bleeding. Seizures or small strokes can also occur because of bleeding into the brain.

A physical examination is usually the only thing needed to make a diagnosis. There is often a family history of HHT and an experienced physician can detect telangiectases during a physical examination. X-rays, echocardiogram, blood tests, blood gas tests and endoscopies are other tests that may be used to help in the diagnosis of HHT.

Hereditary Hemorrhagic Telangiectasia affects 1 in 5,000 people and affects all genders and races equally. Genetic Counseling may be needed for parents who have a family history of the disorder.