Hereditary Hemorrhagic Telangiectasia (Osler-Weber-Rendu Syndrome)

Hereditary Hemorrhagic Telangiectasia (Osler-Weber-Rendu Syndrome) is a genetic disorder that affects the blood vessels throughout the body. It causes abnormal connections between arteries and veins called telangiectasias and larger arteriovenous malformations (AVMs). These abnormal vessels are fragile and prone to bleeding, leading to frequent nosebleeds, visible red spots on the skin, and bleeding in organs like the lungs, liver, and brain. The condition primarily involves the vascular system and can cause serious complications such as anemia from chronic blood loss or stroke from AVMs. It is inherited in an autosomal dominant pattern, meaning it often runs in families. People with this condition may notice symptoms starting in childhood or early adulthood.

Hereditary Hemorrhagic Telangiectasia (HHT) is an autosomal dominant disorder characterized by the development of multiple telangiectasias and arteriovenous malformations (AVMs) due to mutations in genes involved in TGF-β signaling such as ENG and ACVRL1. These mutations lead to abnormal vascular development and fragile blood vessels that lack a normal capillary bed, resulting in direct artery-to-vein shunts. The hallmark clinical features include recurrent epistaxis, mucocutaneous telangiectasias, and visceral AVMs affecting the lungs, liver, and brain. The disease is significant because these vascular malformations can cause life-threatening hemorrhages, high-output heart failure, and paradoxical emboli. Diagnosis is based on clinical criteria supported by family history and genetic testing. Management focuses on preventing and treating bleeding and complications from AVMs.