This has been interpreted as an indication that current targets for vitamin D repletion therapy in CKD may be too low [19], because the mean serum 25(OH)D of 92.5 ng/mL in the 5th quintile was not associated with undesirable changes in safety parameters, but did result in a progressive increase in the percentage of patients with parathyroid hormone reductions ≥ 30%. The gene discussed is PTH; the disease is chronic kidney disease.