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 the ACVRL1, ENG, and SMAD4 genes. 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. Source: Genetic and Rare Diseases Information Center (GARD), supported by ORDR-NCATS and NHGRI.