RasGAP and EphB4 are clinically important in vascular disorders where mutations in RASA1 and EPHB4 are causal for the most common neonatal neurovascular disorder, vein-of-Galen malformations, and one of the major neurovascular disorders, capillary malformation-arteriovenous malformation syndrome (21, 22, 23, 24). The gene discussed is RASA1; the disease is capillary malformation.