Some of the overgrowth syndromes present with confined overgrowth of one or a few regions of the body, e.g., BWSp, PTEN- and PIK3CA-associated disorders (PHTS, PROS), Proteus syndrome (PS), Parkes-Weber syndrome (PKWS), CLOVES (Congenital Lipomatous asymmetric Overgrowth of the trunk with lymphatic, capillary, venous, and combined-type Vascular malformations, Epidermal naevi, Scoliosis/Skeletal and spinal anomalies Syndrome) and Klippel-Trenaunay-syndrome (KTS). This evidence concerns the gene PIK3CA and overgrowth syndrome.