Hereditary hemorrhagic telangiectasia
Hereditary hemorrhagic telangiectasia Causes
Hereditary hemorrhagic telangiectasia type 1 is brought about by mutations in the gene ENG. Type 2 is brought about by mutations in the gene ACVRL1. Juvenile polyposis/hereditary hemorrhagic telangiectasia syndrome is brought about by mutations in the gene SMAD4. All these genes provide instructions for producing proteins that are found in the lining of the blood vessels. These proteins interact with growth factors that control the development of blood vessels. The gene involved in hereditary hemorrhagic telangiectasia type 3 is unknown, but is believed to be located on chromosome 5.
Hereditary hemorrhagic telangiectasia Definition
Hereditary hemorrhagic telangiectasia (HHT) is a disorder that leads to the development of multiple abnormalities in the blood vessels.
Hereditary hemorrhagic telangiectasia Diagnosis
When HHT is suspected, physical examination concentrates on inspecting the whole skin for teleangiectasias, auscultation of the lungs and liver, and neurological examination.
Hereditary hemorrhagic telangiectasia Symptoms and Signs
HHT is marked by telangiectasia (small vascular malformations) on the skin and mucosal linings, epistaxis (nosebleeds), and arteriovenous malformations (AVMs) in various internal organs. Skin and mucosa telangiectasias are most pronounced on the tongue, hands/fingers, nose, lips, mouth/throat and conjunctiva.
Hereditary hemorrhagic telangiectasia Treatment
There is no specific treatment for HHT. Anemia as a result of bleeding from digestive tract AVMs often necessitates repeated blood transfusions. AVMs in critical organs often require surgery.