Endocrine Abstracts

Osteoporosis is a common skeletal disease characterized by low bone mass and microarchitectural deterioration with increased susceptibility to fracture. Osteoporosis has a complex etiology and is considered to be a multifactorial polygenic disease. There are more than 150 genes associated with bone mineral density. Our aim was to investigate the frequency of occurrence of vitamin D receptor (VDR) – (FokI, BsmI, ApaI, TaqI) – single nucleotide polymorphisms (SNPs) in type 1 diabetic patients.

Materials and methods: We studied 62 type 1 diabetic (T1D) patients (26 men and 36 women; mean age 31.46±8.55; duration of the disease 13.40±7.41; HBA1C 8.25±0.95%). Bone mineral density was measured by dual-energy X-ray absorptiometry. QIAamp DNA Blood Mini Kit (Qiagen) was used to purify DNA from whole blood, gene polymorphisms were detected in PCR-RFLP (restriction fragment length polymorphism) analysis. The following restriction enzymes were used to determine the appropriate polymorphism: VDR-FOKI - FokI (BseGI), VDR-BSMI - BsmI (Mva1269I), VDR-TaqI - TaqI, VDR-ApaI – ApaI. Patients with co-morbidities and conditions associated with low BMD were excluded from the study.

Results: VDR-FokI SNP was detected in 40% of cases; VDR-BsmI – in 56% of cases; VDR-TaqI – in 47% of cases; VDR-ApaI – in 38% of cases. There were 37% of homozygotes with VDR-FokI, 35% – with VDR-BsmI, 6% – with VDR-TaqI and 34% with VDR-ApaI.

Conclusion: The results of the study reflect the high frequency of vitamin D receptor (VDR) - (FokI), BsmI, ApaI, TaqI) SNPs which probably may explain the occurrence of low bone mineral density in type 1 diabetic patients.