GSTM1 and chronic kidney disease: Significant differences in expression of genes coding for insulin-like growth factor binding protein 1 (IGFBP1), KIM1, Glutathione-S-transferase mu 1 (GSTM1), glutamate-cysteine ligase catalytic subunit (GCLC) was observed in CKD and CKDu patients in varying degrees compared to healthy controls.