Vitamin D receptor gene polymorphisms: influence on bone metabolism in type 1 diabetic patients

Dilek Gogas Yavuz; Dilek Yazici; Meral Yüksel; Sinem Kiyici; Murat Sert; Ibrahim Sahin; Lerzan Keskin; Oguzhan Deyneli; Hasan Aydin; Ercan Tuncel; Sema Akalin

P396

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Endocrine Abstracts (2007) 14 P396

ECE2007 Poster Presentations (1) (659 abstracts)

Vitamin D receptor gene polymorphisms: influence on bone metabolism in type 1 diabetic patients

Dilek Gogas Yavuz ¹ , Dilek Yazici ¹ , Meral Yüksel ² , Sinem Kiyici ³ , Murat Sert ⁴ , Ibrahim Sahin ⁵ , Lerzan Keskin ⁵ , Oguzhan Deyneli ¹ , Hasan Aydin ¹ , Ercan Tuncel ⁴ & Sema Akalin ¹

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¹Marmara University Medical School, Istanbul, Turkey; ²Marmara University School of vocational, Istanbul, Turkey; ³Uludag University Medical School, Bursa, Turkey; ⁴Cukurova University Medical School, Adana, Turkey; ⁵Inonu University Medical School, Malatya, Turkey.

Patients with type 1diabetes mellitus are at higher risk of developing osteoporosis. Among the genetic factors related to the development of osteoporosis, a possible association between vitamin D receptor (VDR) gene polymorphism and bone mineral density (BMD) has been described in some populations.

The aim of this study is to investigate the distribution of vitamin D receptor (VDR) polymorphisms and relation to bone turnover parameters and bone densitometry in Turkish type 1 diabetic patients/

One hundred nine type 1 diabetic patients (M/F 59/50, 30±7 yrs) and 109 healthy controls (M/F 62/47, 29±8 yrs) were included in the study. Duration of diabetes was 8.1±6.3 yrs in patients. Bone mineral density (BMD) of the lumbar spine (L2–L4) and femoral neck were evaluated by DEXA scans. VDR genotype was assessed by polymerase chain reaction amplification followed by BsmI, Apa, Taq and Fok digestion on DNA isolated from peripheral blood leukocytes. Serum levels of calcium, osteocalcin, parathyroid hormone, ctx, 25-OH-vitamin D levels, and A1c, urinary deoxypyridinoline levels were measured Data were analyzed using the chi.2-test and students T test where appropriate.

Genotypes FF, Ff and ff were 55.9%, 36.6%,7.3% vs 37.6%, 32.6%, 8.4%; BB Bb and bb were 20.1%, 39.4%, 40.3% vs 15.5%, 53%, 31.5%; TT, Tt, tt were 33.9%, 58.6%,18.4% vs 28.4%, 55.9%, 15.5% for diabetic and control groups respectively. And distributions did not differ between the groups. Genotype AA, Aa, aa were 32.1%, 47.7%, 20.1% for diabetics and 24.7%, 62.5%,12.8% for controls and significantly different (P=0.04). Type 1 diabetic group had a lower BMD at femoral and lomber areas compared with the control group. BMD at the head of femur and serum osteocalcin levels tend to be lower at ff genotype in diabetic patients compared to controls.

These findings suggest a small influence of VDR gene polymorphism on BMD in our group of type 1 diabetic patients. Fok1 polimorfisms may have interaction on bone metabolism and requires further studies of larger cohorts.