CCS and diabetic kidney disease: Genetic polymorphisms in genes coding for secreted phosphoprotein 1 (SPP1), thyroid peroxidase (TPO), copper chaperone for superoxide dismutase (CCS), clusterin (CLU), arachidonate 12-lipoxygenase (ALOX12), interaction protein for cytohesin exchange factors 1 (IPCEF1), oxidation resistance 1 (OXR1), aldehyde oxidase 1 (AOX1), nitric oxide synthase 3 (NOS3), and in prion protein (PRNP) conferred protection against development of DKD.