Polymorphisms of pentanucleotide repeats (tttta)n in the promoter of CYP11A1 and their relationships to polycystic ovary syndrome (PCOS) risk: a meta-analysis

Polycystic ovary syndrome (PCOS) is one of the most common endocrine diseases with an uncertain pathology and the most frequent incretory disorder in women of reproductive age, often leading to female infertility. Evidence has shown that genetic factors may contribute to the etiology of PCOS. Contradictory results have been reported concerning the association between PCOS and the CYP11A1 gene promoter -528 bp pentanucleotide (tttta)n repeat polymorphism. In order to get an overall understanding of the association between the CYP11A1 gene promoter -528 bp pentanucleotide (tttta)n repeat polymorphism and PCOS, case-control studies regarding this association were extracted from MEDLINE, Ovid EMBASE and PubMed and pooled for meta-analysis. In dichotomous allelic analyses with 1,236 PCOS patients and 1,306 control subjects, the odds ratios (ORs) were very close to 1. In dichotomous genotypic analyses with 1,063 PCOS patients and 1,176 control subjects, the (tttta)4 genotype may increase the risk of PCOS in a recessive model with OR 1.44, 95 % confidence interval (CI) 1.12-1.85, and the (tttta)6 genotype may decrease the risk of PCOS in a dominant model with OR 0.76, 95 % CI 0.61-0.93. In continuous analyses with 1,085 PCOS patients and 1,216 control subjects, the Mean Difference (MD) was -0.07 with a 95 % CI -0.18 to 0.05, showing no difference between PCOS and control groups. No publication bias was found in either dichotomous or continuous analyses. Taken together, there may be an association between CYP11A1 promoter pentanucleotide repeat polymorphism and PCOS. Further research is needed to strictly confirm our findings.