Phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha (PIK3CA; MIM # 171834) gene-related overgrowth (and vascular malformation) syndromes comprise a heterogeneous group of rare, congenital, segmental overgrowth phenotypes underlying somatic activating mutations of genes in the PI3K/AKT/mTOR pathway [1–6]. The gene discussed is PIK3CA; the disease is vascular malformation.