In partnership with our HTC, UF Health is a Hereditary Hemorrhagic Telangectasia (HHT) Center of Excellence.
HHT is most commonly caused by a mutation in the either the ENG or ACVRL-1 (or ALK-1) genes which account for about 80% of cases. There are other genes that have been associated with HHT including SMAD4, GDF2, and RASA1. It occurs at a rate of 1 in 5,000 people. It is generally inherited in an autosomal dominant fashion, so both boys and girls can have it and there is not a carrier, or silent, state. HHT is associated with bleeding caused by abnormal blood vessel development where an artery grows directly into a vein without becoming a capillary first (an arteriovenous malformation or AVM). A telangiectasia looks like a web of small blood vessels on the surface of the skin because it is an AVM that occurs right underneath the skin. This transition point of the vessels is more fragile than the typical blood vessel and because of higher pressures exerted directly by the arterial circulation to the vein, it is more prone to rupturing and bleeding. If the AVM is large, the bleeding could be catastrophic.
In children, HHT presents most frequently as constantly recurring nose bleeds, and the AVM that are found are frequently relatively small. Other AVM in the lungs and brain may also be found during childhood and may occasionally rupture. In addition, children may develop iron deficiency as a result of frequent bleeding. We screen for these things during our clinic visits. Diagnosis is made with genetic testing and/or based on clinical criteria (Curacao Critera: 2-3 or more including nosebleeds, telangiectasia, AVM, and family history). Treatment is supportive with a reliance on prevention, local measures such as ice and pressure, antifibrinolytic drugs (aminocaproic acid and tranexamic acid), nasal cautery and antiangiogenic drugs. Dr. Ali Ataya is leading a study to look at the effectiveness of antiangiogenic therapy.