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hereditary hemorrhagic telangiectasia
MIM.187300 9q34.1
Friday 3 October 2003
Definition: Hereditary hemorrhagic telangiectasia (HHT) is a genetic angiodysplasia affecting multiple organs, characterized by cutaneous, mucosal, and visceral vascular anomalies.
Hereditary hemorrhagic telangiectasia (HHT) is an autosomal dominant vascular dysplasia leading to telangiectases and arteriovenous malformations of skin, mucosa, and viscera. Epistaxis and gastrointestinal bleeding are frequent complications of mucosal involvement. Visceral involvement includes that of the lung, liver, and brain.
The most frequent form of hereditary hemorrhagic telangiectasia maps to the long arm of chromosome 9 (HHT1) and is due to mutations in the ENG gene coding for endoglin.
Types
hereditary haemorrhagic telangiectasia (HHT)
- HHT1 at 9q34.1 (MIM.187300) : endoglin (ENG) (MIM.131195)
- HHT2 at 12q11-q14 (MIM.600376) : ACVRL1 gene (MIM.601284)
hereditary haemorrhagic telangiectasia with digestive juvenile polyposis (JHPT)
Synopsis
vascular lesions (26%) (12843319)
- telangiectases
- mucosal telangiectases
- conjunctival telangiectases
- nail bed telangiectases
- finger pad telangiectases
- digestive angiodysplastic lesions (esophagus, stomach, small intestine colon) (14%) (12843319)
- arteriovenous malformations (AVM)
- pulmonary arteriovenous malformation (PAVM) (4%) (12843319)
- cerebral arteriovenous malformation (CAVM) (3%) (12843319)
- coronary arteriovenous malformation (9671858)
- celiac arterioveinous malformation
- mesenteric arterioveinous malformation
- hepatic arterioveinous malformation (and cirrhosis)
- cerebral arterioveinous malformation
- spinal arterioveinous malformation
- pulmonary capillary hemangiomatosis (14991548)
- arterial aneurysms
- venous varicosities
hemorrhages
- epistaxis
- subarachnoid hemorrhage
- intracerebral hemorrhage
- digestive hemorrhages
Variants
HHT and digestive juvenile polyposis (JHT syndrome) (MIM.175050) (11795766, 9892274, 8165825)
- MADH4 (SMAD4) mutations (MIM.600993) at 18q21.1
Etiology
Locus HHT1: mutation in the gene encoding endoglin (ENG) (MIM.131195) at 9q34.1
Locus HHT2: mutations in the activin receptor-like kinase-1 gene (ACVRLK1) (MIM.601284) at 12q11-q14
Locus HHT3 (localization unknown; gene unknown)
Locus JP-HHT (juvenile polyposis and HHT): MADH4 mutations (MIM.600993) at 18q21.1