Hereditary Hemorrhagic Telangiectasia (HHT)

Hereditary hemorrhagic telangiectasia (HHT), formerly Osler-Weber-Rendu, is an inherited (autosomal dominant) disease that results in malformed blood vessels (see Telangiectasia on the Tongue). The disease is named after the physicians who first independently described the condition: Henri Jules Louis Marie Rendu in 1896, William Osler in 1901, and Frederick Parkes Weber in 1907. The malformations typically manifest as mucocutaneous telangiectasias and visceral arteriovenous malformations (AVMs). These vascular malformations are responsible for much of the clinical bleeding associated with this disease, ranging from mild epistaxis to life-threatening intracranial bleeds. Some patients with HHT develop pulmonary hypertension, a prothrombotic state, or immune dysfunction. The earliest clinical sign of HHT, often occurring by the second decade of life, is recurrent epistaxis. Telangiectasias, which are dilated blood vessels, are frequently present on the skin and buccal mucosa in the third decade of life. The number of telangiectasias increases with age, accompanied by increased frequency of epistaxis or gastrointestinal (GI) bleeds, leading to anemia, poorer quality of life, and increased healthcare resource utilization, including iron or blood transfusions and hospitalizations.