Segmental overgrowth, or lateralized overgrowth, includes the phosphoinositide-3-kinase, catalytic, alpha polypeptide (PIK3CA) − related overgrowth spectrum (PROS), mosaic RASopathies, PTEN hamartoma tumor syndrome and Beckwith–Wiedemann spectrum [1, 2]. This evidence concerns the gene PIK3CA and PTEN hamartoma tumor syndrome.