Hereditary Hemorrhagic Telangiectasias (HHT), also known as Osler-Weber-Rendu syndrome, is a rare genetic disorder characterized by the development of abnormal blood vessels called telangiectasias throughout various organs of the body. These blood vessels are fragile and prone to rupture, leading to recurrent nosebleeds, gastrointestinal bleeding, and arteriovenous malformations (AVMs).
HHT is an autosomal dominant disorder, meaning that an affected individual has a 50% chance of passing the condition onto their children. It is caused by mutations in genes involved in the formation and maintenance of blood vessels, particularly the endoglin (ENG) and activin receptor-like kinase 1 (ACVRL1) genes. These mutations disrupt the normal signaling pathways responsible for blood vessel formation and stability.
The most common symptoms of HHT include frequent and severe nosebleeds (epistaxis), often beginning in childhood, and telangiectasias on the skin and mucous membranes. These small, reddish-purple clusters of blood vessels may appear on the lips, tongue, fingertips, and the linings of the nose, mouth, gastrointestinal tract, and lungs.
HHT can affect multiple organs, leading to various complications such as iron deficiency anemia due to chronic bleeding, digestive tract hemorrhage, stroke or brain abscess caused by AVMs in the brain, and the development of pulmonary AVMs, which can increase the risk of stroke or brain abscess if left untreated.
Diagnosis of HHT is typically based on clinical criteria, including the presence of characteristic symptoms and findings on examination. Genetic testing can confirm the diagnosis and identify the specific gene mutation involved.
Treatment focuses on managing symptoms and preventing complications. This includes regular monitoring, medication
