To the best of our knowledge no studies are available that would systematically describe the patterns of serum and urine Dkk3 concentrations in patients representing the major groups of ‘kidney’ patients, i.e., those with proteinuria in the course of biopsy-proven glomerular pathology, established CKD (with GFR permanently reduced below 60 mL/min/1.73 m2), kidney transplant recipients and patients with end-stage renal disease (ESRD) treated with hemodialysis. This evidence concerns the gene DKK3 and chronic kidney disease.