Objective: To investigate the distribution of (tttta) n microsatellite polymorphism in the promoter of CYP11a gene in Chinese women with polycystic ovary syndrome (PCOS) and the relationship between such polymorphism and PCOS.
Methods: Peripheral blood samples were obtained from 201 women with PCOS, aged 26 +/- 4, and 147 women without PCOS, aged 29 +/- 5. Radioimmunoassay was used to examine the levels of testosterone, follicle-stimulating hormone, luteinizing hormone, progesterone, estradiol, and prolactin. Locus-specific prime PCR was used to detect the frequencies of the CYP11a alleles. Body mass index (BMI) was calculated.
Results: The average BMI of the women with PCOS was 22 kg/m(2) +/- 4 kg/m(2), and that of the non-PCOS women was 22 kg/m(2) +/- 6 kg/m(2). The six-repeat allele variant genotypic distribution of CYP11a was statistically different between the women with PCOS and those without PCOS [Fisher's exact test (2-tail), P = 0.031]. The frequency of 6//6 genotype in the PCOS patients was 57.7% (116/201), significantly higher than that of the non-PCOS women [44.9% (66/147), chi(2) = 5.588, P = 0.018]. The BMI of the PCOS patients with 4//4 genotype was 19.4 kg/m(2) +/- 1.7 kg/m(2), statistically lower than those of the PCOS patients with 4//6, 6//6, and 6//8 genotypes (23.6 kg/m(2) +/- 3.3 kg/m(2), 22.5 kg/m(2) +/- 3.8 kg/m(2), 22.2 kg/m(2) +/- 4.2 kg/m(2) respectively, P = 0.0037, 0.0027, and 0.059 respectively). The PCOS patients with the allele (tttta) 6 had markedly higher BMI (22.7 kg/m(2) +/- 3.7 kg/m(2)) than those without the allele (tttta) 6 (19.4 kg/m(2) +/- 1.7 kg/m(2), P = 0.0075). No differences were observed in the serum levels of reproductive hormones among the individuals with different genotypic features in the PCOS patients.
Conclusion: The six-repeat allele is the most common fragment of (tttta) n microsatellite polymorphism in Chinese Han woman. The 6//6 genotype is significantly more frequent and is associated with greater BMI in the women with PCOS. The six-repeat allele variant may play a certain role in the pathogenesis of PCOS.