Hereditary Hemorrhagic Telangiectasia (Arteriovenous Malformation)

Hereditary Hemorrhagic Telangiectasia (HHT) is a genetic disorder that affects the blood vessels, causing them to develop abnormally. This condition leads to the formation of fragile, enlarged blood vessels called telangiectasias and larger abnormal connections known as arteriovenous malformations (AVMs). These abnormal vessels can cause frequent nosebleeds, visible red spots on the skin, and bleeding in various organs. The main health concern is that these fragile vessels can rupture, leading to bleeding and complications such as anemia or stroke. HHT primarily involves the vascular system and can affect the skin, mucous membranes, lungs, liver, and brain.

Hereditary Hemorrhagic Telangiectasia (HHT) is an autosomal dominant disorder characterized by the presence of multiple telangiectasias and arteriovenous malformations (AVMs) due to mutations in genes such as ENG and ACVRL1 that disrupt TGF-β signaling in vascular endothelial cells. The core pathology involves direct connections between arteries and veins without an intervening capillary bed, leading to fragile vessels prone to rupture. Clinically, HHT manifests with recurrent epistaxis, mucocutaneous telangiectasias, and visceral AVMs that can cause serious complications like hemorrhage, stroke, or high-output heart failure. The disorder is significant for its variable expressivity and potential for life-threatening bleeding or embolic events. Diagnosis often involves clinical criteria supported by imaging studies to detect AVMs.