The area of EC research was enforced by the finding that the human disease hereditary hemorrhagic telangiectasia 1 (HHT-1) is based on genetic defects in the endoglin gene (Eng), leading to defect/non-functional or mis-targeted proteins causing haploinsufficiency in Endoglin [1,37,38,39,40]. Here, ENG is linked to telangiectasia, hereditary hemorrhagic, type 1.