Studies on the frequencies of vitamin D receptor gene polymorphism in postmenopausal women of Han and Kazak nationality in China

Polymorphyism of the vitamin D receptor (VDR) gene is reported to play a major role in variations of the genetic regulation of bone mass. The role of VDR polymorphisms within various ethnic populations is also undetermined. The purpose of the present study was to determine the frequencies of VDR genotypes in the Han and Kazak nationalities in China. We analyzed the polymorphism defined by the Bsm1 restriction enzyme using polymerase chain reaction-restriction fragment length polymorphism in 179 healthy postmenopausal Han women and 63 healthy postmenopausal Kazak women. The genotype frequencies of the VDR were calculated later using the Hardy-Weinberg equilibrium formula. The results showed that for women of Han nationality, the bb, Bb, and BB genotypes accounted for 90.5%, 9.5%, and 0%, respectively. In Kazak women, the respective frequencies were 38.1%, 55.56%, and 6.35%. We found that there was a significant difference between women of Han and Kazak nationality in terms of the frequency of distribution of VDR genotype (P<0.001). There was a similar distribution of VDR genotypes in Kazak women to that seen for the Caucasian population of the USA. The results of the present study provide further evidence on the different pathogeny of osteoporosis in various ethnic groups.