Hereditary Hemorrhagic Telangiectasia: On the Brink of a New Treatment Era?

Hereditary hemorrhagic telangiectasia (HHT) is an inherited vascular disorder with highly variable penetrance, affecting up to 1 in 5,000 individuals. It is characterized by the presence of abnormal blood vessels that can lead to excessive bleeding-most frequently recurrent nosebleeds (epistaxis), skin and mucosal telangiectasias (small, dilated blood vessels), as well as arteriovenous malformations (AVMs) that can form in various organs, particularly the lungs, liver, and brain. HHT is caused by loss-of-function mutations in the BMP9-10/ENG/ALK1/SMAD4 signaling pathway, an important mediator of vascular quiescence.