Vitamin D receptor genotypes are associated with bone mass in patients with Turner syndrome

Background: Turner syndrome (TS) patients present low bone mineral density (BMD) and increased fracture risk, probably due to a genetic defect aggravated by hormonal deficiency. Aim: To study the relationship between vitamin D receptor (VDR) gene polymorphisms and BMD and bone parameters in TS patients. Methods: DNA from 65 TS patients and 110 controls was amplified by PCR and digested with FokI, BsmI and ApaI restrictases. Lumbar and femoral BMD were determined by DEXA and serum intact parathyroid hormone, osteocalcin and beta-CrossLaps by electrochemiluminescence. Results: Genotype distribution within the ApaI site was different in both groups: genotype Aa was more abundant in TS (63.8% vs. 41.3%; p < 0.01), whereas AA predominated in controls (33.9% vs. 15.5%; p < 0.01). Patients carrying genotype bb (BsmI) or ff (FokI) had lower BMD than those with other genotypes (p < 0.01 and p < 0.05, respectively). Conclusion : BsmI and FokI polymorphic sites of VDR could be genetic determinants of BMD in TS patients.