Absence of the high risk 's' allele associated with osteoporosis at the intronic SP1 binding-site of collagen 1a1 gene in Southern Chinese

Abstract

The Sp1 polymorphism in the first intron of the collagen Ia1 gene was recently described to be associated with low bone mineral density (BMD) and increased fracture risk in Caucasion populations. The impact of this gene was assessed in a southern Chinese population. 181 women, aged 51.1 8.8 years were evaluated for the Sp1 polymorphism. 22% of the women were classified as having osteoporosis on the basis of a T-score at the lumbar spine or the hip below ±2.5 with or without a prevalent fracture. Genotype analysis was performed by PCR amplification and restriction enzyme digestion. Single-strand conformational polymorphism analysis (SSCP) was performed in 65 randomly selected samples to search for any polymorphic site in the PCR amplified region. The results showed that no restriction enzyme site could be identified in any of the 181 samples analyzed. Moreover SSCP analysis revealed no polymorphism in the PCR amplified region of the first intron of the collagen Ia1 gene. In conclusion, the `s' allele, associated with low BMD and increased fracture risk in Caucasians, is non-existent or very rare in the southern Chinese population. The absence of this `high risk' allele may in part account for the reduced fracture risk observed in the Chinese in comparison to Western populations.