Hereditary Hemorrhagic Telangiectasia (HHT), also known as Osler-Weber-Rendu syndrome, is a rare genetic disorder characterized by abnormal blood vessel formation. This condition primarily affects the blood vessels in various organs, leading to the development of fragile, enlarged, and abnormal blood vessels called telangiectasias. These telangiectasias can occur in multiple areas of the body, including the skin, mucous membranes, and internal organs.
HHT is an autosomal dominant disorder, meaning that a person only needs to inherit one copy of the mutated gene from either parent to develop the condition. The most common genes associated with HHT are ENG and ACVRL1, which are involved in the formation and maintenance of blood vessels. Mutations in these genes disrupt the normal signaling pathways that regulate blood vessel development, leading to the characteristic vascular abnormalities seen in HHT.
The symptoms of HHT can vary widely among affected individuals. Common signs include recurrent nosebleeds (epistaxis), telangiectasias on the skin and mucous membranes, and arteriovenous malformations (AVMs) in various organs such as the lungs, liver, brain, and gastrointestinal tract. These AVMs can cause serious complications, including internal bleeding, stroke, and organ dysfunction.
Diagnosis of HHT involves a combination of clinical evaluation, family history assessment, and genetic testing. Treatment aims to manage the symptoms and prevent complications. This may involve interventions such as laser therapy to treat telangiectasias, embolization or surgery to address AVMs, and medications to control bleeding and other associated symptoms.
It is important for individuals with HHT to receive regular medical monitoring and care from a multidisciplinary team of specialists, including geneticists, hematologists, pulmonologists, and gastroenterologists. Genetic counseling is also recommended for affected individuals and their families to understand the inheritance pattern and potential risks.