ACVRL1 and hereditary hemorrhagic telangiectasia: Loss-of-function mutations in the endoglin gene (ENG) lead to HHT type 1, which, together with the HHT type 2 (resulting from mutations in ACVRL1/ALK1), account for more than 90% of all patients with HHT diagnosed using the well-established clinical criteria of Curaçao [79–81].