FokI Polymorphism at Translation Initiation Site of the Vitamin D Receptor Gene Predicts Bone Mineral Density and Vertebral Fractures in Postmenopausal Italian Women

• Published in: Journal of bone and mineral research Vol. 14; no. 8; pp. 1379 - 1386
• Main Authors: Gennari, Luigi, Becherini, Lucia, Mansani, Riccardo, Masi, Laura, Falchetti, Alberto, Morelli, Annamaria, Colli, Emanuela, Gonnelli, Stefano, Cepollaro, Chiara, Brandi, Maria Luisa
• Format: Journal Article
• Language: English
• Published: Washington, DC John Wiley and Sons and The American Society for Bone and Mineral Research (ASBMR) 01.08.1999; American Society for Bone and Mineral Research
• Subjects: Aged; Analysis of Variance; Biological and medical sciences; Bone Density - physiology; Bone Diseases, Metabolic - genetics; Deoxyribonucleases, Type II Site-Specific - genetics; Diseases of the osteoarticular system; Female; Fundamental and applied biological sciences. Psychology; Genetics of eukaryotes. Biological and molecular evolution; Genotype; Human; Humans; Italy; Medical sciences; Middle Aged; Osteoporosis, Postmenopausal - genetics; Osteoporosis. Osteomalacia. Paget disease; Peptide Chain Initiation, Translational - genetics; Polymorphism, Genetic; Population genetics, reproduction patterns; Postmenopause - physiology; Receptors, Calcitriol - genetics; Spinal Fractures - genetics; Italy; Europe; Human; Pathologic fracture; Diseases of the osteoarticular system; Translation initiation; Vertebra; Bone disease; Population genetics; Trauma; Density; Inorganic element; Osteoarticular system; Osteoporosis; Restriction fragment length polymorphism; Vitamin D; Female; Bone; Osteopenia; Biological receptor
• ISSN: 0884-0431; 1523-4681
• DOI: 10.1359/jbmr.1999.14.8.1379

A novel T/C polymorphism (ATG to ACG) at the translation initiation site of the vitamin D receptor (VDR) gene, defined by FokI restriction endonuclease, has been recently associated with variation in bone mineral density (BMD) and rates of bone loss in a group of postmenopausal Mexican‐American women. The presence of the restriction site, designated as f, allows protein translation to initiate from the first ATG, while the allele lacking the site, indicated as F, initiates translation at a second ATG. In this study, we investigated the role of FokI polymorphism in a group of 400 postmenopausal women of Italian descent stratified for BMD into osteoporotic (n = 164), osteopenic (n = 117), and normal (n = 119) groups. There were 159 (41%) FF homozygotes, 55 (14%) ff homozygotes, and 186 (45%) Ff heterozygotes. In the whole population, we observed a weak association between FokI polymorphism and lumbar BMD (p = 0.06, analysis of covariance [ANCOVA]) but not with femoral neck BMD (p = 0.5, ANCOVA). Interestingly, the effect of FokI genotypes on lumbar BMD was influenced by the years since menopause such that differences in BMD related to different VDR allelic variants were greater among women in the first 5 years of menopause (p = 0.04, ANCOVA), progressively declining afterward. In addition, a significantly higher prevalence of ff genotype in osteoporotic than in osteopenic and normal women was observed (p = 0.04, Chi‐square test). Finally, ff genotype resulted significantly over‐represented in the group of women with a vertebral fracture as compared with controls (p = 0.003, Chi‐square test), equivalent to a relative risk of 2.58 (95% confidence intervals 1.36–4.91). We conclude that in this population, FokI polymorphism at the VDR gene locus accounts for a part of the heritable component of BMD at the lumbar spine.