Gene dose effect between a fat mass and obesity-associated polymorphism and body mass index was observed in Korean women with polycystic ovary syndrome but not in control women

Objective: To examine the association between fat mass and obesity-associated (FTO) polymorphisms and polycystic ovary syndrome (PCOS) in Korean women. Design: Case-control study. Setting: University department of obstetrics and gynecology. Patient(s): Women with (n = 552) or without (n = 559) PCOS. Intervention(s): Genotyping was performed. Main Outcome Measure(s): FTO rs9939609 genotype distribution and correlation between variants in this gene and PCOS phenotypes. Result(s): The mean body mass index (BMI) of the patients was significantly higher than that of the control subjects (22.0 +/- 4.1 kg/m(2) vs. 20.1 +/- 2.5 kg/m(2)), but most (81.3%) of the patients were not obese. FTO rs9939609 was not significantly associated with PCOS itself. However, a positive correlation was observed between the number of variant alleles and BMI in women with PCOS: Each additional copy of the variant allele increased BMI by a mean (95% confidence interval) of 4.8% (1.4%-8.3%) or 1.11 kg/m(2) (1.03-1.20 kg/m(2)) after adjusting for age. This correlation was not observed in the control subjects. Conclusion(s): FTO rs9939609 was not a major determinant of PCOS. However, in the women with PCOS who were primarily nonobese, a gene dose effect was observed for BMI. The FTO gene may play an influential role in predisposition to PCOS via an association with obesity. (C) 2014 by American Society for Reproductive Medicine.