As expected, there were significant differences between the Vitamin D3 and FGF23 levels in patients with CKD as compared to healthy donors (Fig. 1b), 22.3 ng/mL vs 28.9 ng/mL and 485.6 pg/mL vs 39.4 pg/mL (P < 5 × 10− 4), respectively. This evidence concerns the gene FGF23 and chronic kidney disease.