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

Abstract

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. HHT possesses significant challenges for affected individuals, as the complications can range from mild to life-threatening events, depending on the severity and location of the vascular abnormalities. Despite this bleeding disorder being not uncommon, nowadays no specific treatment is as yet available for HHT and most current therapies include repurposed drugs. The aim of this review was to show therapeutic advances on the basis of recent promising clinical trials for HHT.