FokI Polymorphism of the Vitamin D Receptor Gene Correlates with Parameters of Bone Mass and Turnover in a Female Population of the Italian Island of Lampedusa

Abstract

One of the most promising genetic approaches to dissecting a multifactorial disease is represented by genetically isolated population studies. We studied a genetic marker in a cohort of women living on the Mediterranean island of Lampedusa, a geographically isolated population. Lampedusa, located between the African coast and Sicily, consists of a young genetic isolate (<20 generations) with an exponential growth in the last generations. We analyzed the association between the FokI vitamin D receptor (VDR) gene polymorphism, previously proposed as a predictor of bone mass, with parameters of bone mass and turnover in a cohort of pre- and postmenopausal women living on Lampedusa. In 424 women (277 postmenopausal and 147 premenopausal), allelic frequencies were 49% for the F allele and 51% for the f allele. Using analysis of covariance, we found that subjects with ff genotype exhibited a significantly (P < 0.001) lower lumbar spine bone mass, by dual-energy X-ray absorptiometry, and lower values of bone ultrasonographic parameters (speed of sound and broadband ultrasound attenuation) relative to those with Ff and FF genotypes. Conversely, osteocalcin and serum cross-laps were significantly higher in ff and Ff compared to FF genotype. Our data suggest that FokI VDR polymorphism may contribute to the determination of bone mass and turnover in both pre- and postmenopausal women in this geographically isolated population.