Klippel-Trenaunay and Sturge-Weber Overlap Syndrome with KRAS and GNAQ mutations.

Patients with combined phenotypes of Sturge-Weber syndrome and Klippel-Trenaunay syndrome have been reported, though the underlying genetic spectrum in these individuals remains to be elucidated. We reported the patient presenting with Klippel-Trenaunay and Sturge-Weber overlap syndrome in mainland China. Histopathologic study confirmed the hemangioma of vein and capillary. Co-existence of a novel somatic KRAS c.182_183 delins TC mutation and GNAQ c.548G>A mutation was identified in the affected skin tissue rather than paired peripheral blood. The somatic mutations of GNAQ and KRAS may affect MAPK-ERK signaling pathway, resulting in endothelial anomaly and blood vessel malformation.