In previous studies, sub-dermal arteriovenous malformations (AVMs) are induced in wounds of activin receptor-like kinase 1 (Alk1)-mutant mice, which appeared in the form of both arteries and veins elongation followed by arterial-venous connections de novo (Kim et al., 2011; Laux et al., 2013; Garrido-Martin et al., 2014). The gene discussed is ACVRL1; the disease is arteriovenous hemangioma/malformation.