RASA1 and cutaneous mastocytosis: Variants in RASA1 have been implicated in autosomal dominant type 1 capillary malformation-arteriovenous malformation (CM-AVM1) (OMIM# 608354)60, featuring fast-flow vascular malformations, including systemic and intracranial arteriovenous fistulas and AVMs and, rarely, VOGMs27,30,61.