The association of the FTO rs9939609 polymorphism with obesity and metabolic risk factors for cardiovascular diseases in Polish children.

The phenomenon of excessive body mass increase in the general population of children and adults in the past few decades and has been attributed to environmental changes, especially when superimposed on a predisposing genetic background. The fat mass and obesity-associated (FTO) gene has recently become one of the most extensively investigated genes associated with body mass. The aim of the study was to investigate the association of the FTO rs9939609 T>A single-nucleotide polymorphism with selected anthropometric and metabolic parameters and blood pressure in a large population of Polish children. A total of 968 children aged 4 to 18 years were included in the study. Genotyping was performed using a TaqMan assay. The rs9939609 marker was associated with standardised (standard deviation scores, SDSs) values of body mass, height, body mass index (BMI), waist circumference, hip circumference and arm circumference. When we compared normal-weight with obese children we observed a strong recessive predisposing effect of the A-allele (OR=2.11 95% CI: 1.50-2.99, p=2.23 x 10(-6) for AA vs. TT+AT). Univariate analysis revealed associations of the FTO gene variants with the values of blood pressure, triglycerides, fasting glucose and HOMA insulin resistance index. After taking into account SDS BMI only the association with HOMA remained statistically significant. The FTO gene polymorphism may partially explain the predisposition to obesity in the population of Polish children. The potential effect on the remaining cardiovascular risk factors seems indirect and dependent on BMI changes. The polymorphism may be independently associated with insulin resistance.