ACVRL1 and hereditary hemorrhagic telangiectasia: Such AVMs are common features of hereditary hemorrhagic telangiectasia (HHT), an autosomal dominant vascular disorder that impacts approximately 1 in 5000 people worldwide and is correlated in more than 90% of cases to mutations in ALK1 or ENG (encoding endoglin, a non-signaling BMP9/BMP10 receptor) [28].