The three most prominent among them are: (1) diets which are poor in zinc; (2) a rare autosomal recessive condition called acrodermatitis enteropathica due to mutations in the gene (SLC39A4) which codes the zinc transporter protein, ZIP4; (3) exclusively breast-fed babies as a result of mutations in the SLC30A2 (zinc T-2), a gene which is responsible for transferring zinc from serum to breast milk [4]. The gene discussed is SLC39A4; the disease is acrodermatitis enteropathica.