Another well-described syndrome is capillary malformation–arteriovenous malformation (CM-AVM), caused by mutations in RASA1 (RAS p21 protein activator 1) and EPHB4 (Ephrin type-B receptor 4), characterized by multifocal fast-flow lesions and cutaneous vascular malformations [27,49,51]. The gene discussed is EPHB4; the disease is arteriovenous hemangioma/malformation.