Impact of the FTO gene variation on fat oxidation and its potential influence on body weight in women with polycystic ovary syndrome

Context Polycystic ovary syndrome (PCOS) is a heterogeneous disorder where insulin resistance might be involved in the development of endocrine and metabolic abnormalities. It has recently been shown that the FTO gene modifies weight, fat mass and insulin sensitivity in women with PCOS, where its role might be larger than in other phenotypes. Objective The aim of this study was to estimate the effect of a variation of the FTO gene on carbohydrate and lipid oxidation in PCOS women. Patients The study group consisted of 65 women with PCOS and 28 healthy, normally menstruating women. Measurements Clinical examination, anthropometric measurements, euglycaemic hyperinsulinaemic clamp and measurements of serum sex hormones were performed. Carbohydrate and lipid oxidation were evaluated with indirect calorimetry in the baseline state and during last 30 min of the clamp. The FTO rs9939609 polymorphism was genotyped using the restriction fragment length polymorphism method. Results There were no differences in carbohydrate and lipid oxidation between PCOS and control women. In the PCOS group, TT homozygotes had higher baseline fat oxidation in comparison with carriers of the A allele (P = 0.018), which was not found in the control group. We did not observe the effect of the FTO gene variation on insulin-stimulated lipid oxidation and neither on the baseline nor on the insulin-stimulated carbohydrate oxidation. Conclusion Our data show that this FTO gene variation might influence the baseline lipid oxidation in PCOS patients. This might potentially be one of the mechanisms explaining the impact of the FTO gene on body weight in PCOS.