Historically, different nomenclatures have been used in this group of patients, including but not limited to macrocephaly-capillary malformation [56], MCAP [25], MPPH [25, 30], hemimegalencephaly [26], focal cortical dysplasia [28], megalencephaly [28, 57], and PIK3CA-related overgrowth spectrum [58]. This evidence concerns the gene PIK3CA and hemimegalencephaly.