Several critical signaling pathways regulating angiogenesis, including the ‘vascular endothelial growth factor (VEGF) and VEGF receptors pathway’, ‘PI3K/Akt/mTOR pathway’ and ‘HIF-α-mediated pathway’, have been demonstrated to participate in the development of IH [3, 4]. This evidence concerns the gene AKT1 and isolated hemihyperplasia.