Genetic mouse models of AVMs include those for hereditary hemorrhagic telangiectasia (HHT; Rendu-Osler-Weber syndrome) with mutations in endoglin or activin receptor-like kinase 1 (Alk1) [172,173,174,175,176,177,178] or proteins regulated by Alk1 [62]. This evidence concerns the gene ACVRL1 and hereditary hemorrhagic telangiectasia.