FGF 23, PTH and vitamin D status in end stage renal disease patients affected by VDR FokI and BsmI variants

Abstract

Objectives: The aim of this study was to evaluate the association between two VDR SNPs FokI and BsmI and mineral status in ESRD patients.

Design and methods: Our case-control study included 100 patients with chronic renal failure in ESRD and 149 healthy subjects. We measured the serum Vitamin D levels and the serum intact PTH level by Electrochemiluminescence Technology (cobas E411 analyzer). We evaluated the serum FGF23 levels by indirect ELISA method. The genotyping of two VDR gene variants FokI and BsmI was carried out by PCR-RFLP technique.

Results: In our study, the FokI TT genotype was associated with lower risk of ESRD development (OR = 0.176, Padj = 0.039). The difference in PTH and FGF23 levels between cases and controls was statistically significant. The expression of FokI CT genotype in subjects with diabetic nephropathy was associated with a negative correlation between VD and PTH levels (r = -0.620, P = 0.032) and a positive correlation between VD and FGF23 levels (r = 0.967, P = 0.012). A significant differences in VD levels between patients and controls was observed in the presence of FokI TT (P = 0.044) and CT (P = 0.036) genotypes. The expression of FGF23 serum level was significantly elevated in patients than in controls in the presence of the FokI CC and BsmI AG genotypes.

Conclusions: In conclusion, our study shows the existence of an association between VDR FokI, BsmI polymorphisms and mineral status in ESRD patients. The presence of VDR variants affect the protein expression of VD, phosphorus, FGF23 and PTH.