482 GNAQ Mutation Identified in a Patient with Congenital Capillary Malformation and Soft Tissue Overgrowth

Introduction/Objective Capillary malformations are vascular anomalies affecting ∼2% of newborns. They may occur in isolation or part of a syndromic condition with other features such as soft tissue overgrowth. Genetic testing is increasingly used to aid in the diagnosis and treatment of these conditions. Methods/Case Report This case describes an 8-year-old girl with multiple capillary malformations on her right arm, chest, neck, and back, as well as right arm tissue overgrowth since birth. She presented with a tender subdermal mass on her upper back. Initially suspected to be a reactive lymph node or dermoid cyst, biopsies of the mass and adjacent capillary malformation lesion showed dilated, malformed capillaries and arterioles consistent with capillary malformation. Molecular testing revealed a pathogenic somatic GNAQ c.548G>A (p.Arg183Gln) mutation at variant allele frequency of 5%. Results NA Conclusion This case underscores the clinical variability of vascular anomalies and the utility of molecular profiling in characterizing capillary malformations. The hot spot GNAQ mutation identified has also been identified in isolated capillary malformations and Sturge-Weber syndrome, highlighting that these disorders may exist on a spectrum.