The Relationship between Vitamin D Receptor Gene Polymorphisms and Bone Density, Osteocalcin Level and Growth in Adolescents

Background/Objective: The relationship between vitamin D receptor gene polymorphisms and bone density, osteocalcin and growth was investigated. Subjects: Eighty eight adolescents aged between 8-15, with no history of illness influencing the level of bone parameters, were examined in our study. Methods: Areal BMD for lumbar spine (L1-4) was assessed by dual energy X-ray absorptiometry (DEXA). Height and weight were measured on the day of the DEXA scans. Serum osteocalcin level was determined by using ELISA method. DNA was extracted from white blood cells, amplified by the polymerase chain reaction (PCR) and the polymorphic sites were analyzed by using ApaI, TaqI and FokI restriction enzymes. Results: The most frequent genotypes were FF (% 54.6), Aa (% 53.4) and Tt (% 48.8). No significant relationship was found between VDR genotypes and areal BMD, osteocalcin level or growth in either sex. But there was a strong tendency for a higher BMD at the lumbar spine of TT and AA genotypes compared to tt and Aa genotypes. The children with TT genotype were taller and heavier than the children with tt genotype. Conclusion: Our results suggest that VDR gene TaqI polymorphism may be associated with body weight and bone mass, but more studies with larger groups should be conducted.