Moreover, we recently reported that total PTH and oxPTH substantially increased, whereas noxPTH only moderately increased with the progressive deterioration of kidney function in two independent cohorts of children with CKD and stable renal transplant recipients [41]; this might mean that the increase in PTH with decreasing GFR is mainly due to an increase in oxPTH in more advanced stages of CKD. This evidence concerns the gene PTH and chronic kidney disease.