Clitoromegaly, Vulvovaginal Hemangioma Mimicking Pelvic Organ Prolapse, and Heavy Menstrual Bleeding: Gynecologic Manifestations of Klippel-Trénaunay Syndrome.

Klippel-Trénaunay Syndrome (KTS) is a genetic vascular malformation involving the capillary, lymphatic, and venous channels. Prenatal sonographic diagnosis of KTS with an enlarged fetal limb is well-known; however, postnatal gynecologic manifestations are rarely reported. KTS can cause clitoromegaly, vulvovaginal hemangioma, and heavy menstrual bleeding. Somatic mosaicism of the PIK3CA gene is considered as responsible for KTS but reports based on whole-genome sequencing are limited. A 31-year-old woman with KTS presented with bulging of the clitoris and vagina. Analysis of whole-genome sequencing variant data revealed that gene ontology terms related to development and differentiation such as 'skeletal system morphogenesis', 'embryonic morphogenesis', and 'sensory organ development' were nominally significant in non-coding regions. Variants in non-coding genes may be responsible for this phenotype.