SHANK2 and Zinc deficiency: The critical role of zinc deficiency in etiology of autism has been suggested by recent studies that estimated fetal and postnatal exposure profiles of toxic metals and essential minerals [6,7,16], and that investigated AMPA (α-amino-3-hydroxy-5-methyl-4-isoxazolepropionicacid) receptor subunit switch controlled by zinc and Shank in developing neurons [17,18].