PIK3CA and angioosteohypertrophic syndrome: Vahidnezhad et al. hypothesized that KTS may result from mutations in PIK3CA, the gene involved in the construction of the enzyme PI3K (phosphatidylinositol 3-kinase), cellular proliferation and migration, suggesting that KTS belonged to the PIK3CA-related overgrowth spectrum (PROS) (22, 24).