BsmI polymorphism of the vitamin D receptor gene in hyperparathyroid or hypoparathyroid dialysis patients

Since bone mineral density may be influenced by the polymorphisms of the vitamin D receptor (VDR) gene, we studied whether VDR genotypes might drive the progression toward hyperparathyroidism or hypoparathyroidism in patients with end-stage renal disease. On the basis of their parathyroid hormone (PTH) levels, we divided 99 patients undergoing dialysis into 2 groups: 56 patients with hypoparathyroidism (PTH < 104 pg/mL [< 11 pmol/L]) and 43 with hyperparathyroidism (PTH > 261 pg/mL [> 27.5 pmol/L]). The BB polymorphism was more frequent in patients with hypoparathyroidism (34%) than in patients with hyperparathyroidism (16%), but the difference did not reach statistical significance. Patients with the B allele and BB genotype had a significantly lower dialytic age and serum PTH and alkaline phosphatase levels than patients with the b allele and bb genotype. These results suggest that in end-stage renal disease, the BB genotype may mark a higher risk of developing hypoparathyroidism and diminished bone turnover.