The Sp1 binding site polymorphism in collagen type I alpha 1 gene (COLIA1) has been associated with osteoporosis (OP) and bone mineral density (BMD). The aim of this study was to explore the association of this polymorphism with OP and BMD in the Mexican population by polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP) procedure. Allelic and genotypic frequencies from the Sp1 polymorphism were determined in 100 women with OP, 100 women without OP and 500 subjects from general Mexican population (GMP). Distribution of Sp1 polymorphism was in Hardy-Weinberg equilibrium. In spite of population structure due to racial mix in Mexican population, associations with OP were demonstrated. The frequency of "s" allele was significantly higher in women with OP (35%) than in women without OP (11%; P < 0.00001). Interestingly, "ss" genotype, was exclusive of women with OP and was associated with low BMD (0.588 ± 0.077 g/cm(2)) in contrast to "SS" genotype (0.733 ± 0.039 g/cm(2); P = 0.0001). This work confirms the association of Sp1 polymorphism with low BMD and OP in Mexican population and make sure to use Sp1 as a genetic marker for OP in our population.

Osteoporosis is a common health problem in Mexico, so it is essential to investigate the status of different gene polymorphisms that could serve as genetic susceptibility markers in the Mexican population. Genes with a role in bone metabolism are excellent candidates for association studies. In this study were determined the allelic and genotypic frequencies of four polymorphic markers (C/T rs3736228, G/A rs4988321, T/C rs627174 and T/C rs901824) in the low-density lipoprotein receptor-related protein 5 gene (LRP5) and their association with osteoporosis in 100 pos-menopausal osteoporotic Mexican women and their controls, using real time-PCR and TaqMan probes. Only the G/A polymorphism (rs4988321, Val667Met) showed significant differences (p = 0.039) when genotype frequencies were compared. However, when the haplotypes of these four polymorphisms were analyzed, interesting associations became evident. The CGTT haplotype showed significant association with low risk of osteoporosis (OR 0.629; p = 0.007; [95 % CI, 0.448-0.884]), whereas the TACT haplotype was significantly associated with a higher risk of osteoporosis (OR 7.965; p = 0.006; [95 % CI, 1.557-54.775]). Our results supported the association of LRP5 with osteoporosis and showed the potential value of LRP5 haplotypes to identify risk of osteoporosis in Mexican population.

The results support the association of COL1A1 gene polymorphisms with fracture and with low BMD at the hip in Mexican population.

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