VNTR I/I genotype of insulin gene is associated with the increase of follicle number independent from polycystic ovary syndrome.

BACKGROUND

Polycystic ovary syndrome (PCOS) is accompanied by selective insulin resistance and enhanced ovarian steroidogenic effects of insulin. We analysed the minisatellite variations of the insulin gene (INS VNTR) with regard to the clinical features of PCOS.

METHODS

Retrospective, adjusted association study. Infertile patients with PCOS (n=30) and tubal factor (n=75) were screened for anthropometrical, clinical and ovarian morphology parameters, as well as hormonal values. INS VNTR was genotyped by its surrogate marker at -23 HphI locus.

RESULTS

INS VNTR genotype distribution was similar in PCOS and tubal infertility group. The mean ovarian follicle number was higher in VNTR I/I individuals compared to VNTR I/III and III/III individuals (adjusted OR=1.28, p=0.03), independent from the cause of infertility, the age, the follicle stimulating hormone level on day 3-5 of menstrual cycle, BMI and the previous surgical ovarian tissue removal. In addition, higher level of the luteinising hormone in VNTR I/I individuals was associated with the increase in follicle number.

CONCLUSIONS

We suggest that INS VNTR genotypes are not associated with PCOS in general, but could have a certain influence on the phenotypic spectrum of the syndrome.