1. Contribution of SNPs (rs , rs057044, rs ) and haplotypes of FTO gene to the genetic risk for obesity in children from Yucatan, México.
González-Herrera Lizbeth, López-González María José, Cardeña-Carballo Zenda, Pérez-Mendoza Gerardo, Andrade-Olalde Ana, Pinto-Escalante Doris.
Centro de Investigaciones Regionales. Universidad Autónoma de Yucatán. México.
BACKGOUND
RESULTS
The fat mass and obesity-associated (FTO) gene has been identified as a strong candidate for obesity-related phenotypes in several populations. SNPs might play a transcriptional regulatory role, either to up or downregulate FTO expression. The association of FTO with body mass index (BMI) is largely driven by effects on appetite and food intake. FTO is most highly expressed in the hypothalamus, where the sensing of amino acid levels has been demonstrated to affect orexigenic and anorexigenic pathways controlling food intake. The modest effect size of around 1.5 kg per FTO risk allele in humans, with homozygote carriers being on average 3 kg heavier. Risk alleles result in subtle variations in the expression of FTO in key appetite control centres within the brain, which are likely to influence the way one’s sense and respond to amino acid levels. Human carriers for the FTO risk SNPs actually display quite a nuanced feeding phenotype compared with non-carriers. In test meals, they not only consume more calories in absolute terms, but also show an alteration in nutrient preference
Genotype and allele frequencies for the three SNPs of FTO gene were distributed according to Hardy-Weinberg expectations (p>0.05); except in non-obese children for rs The heterozygous genotype for the three studied SNPs, as well as the allele C for rs showed significant differences between obese and non-obese children (p<0.03) (Table 1), suggesting that these SNPs are associated with the genetic risk for obesity in the studied children population. However mean BMI, waist circunference and waist/height index were not significantly different according to genotype between obese and non-obese children. Haplotype distribution did not show any significant difference between cases and control (p>0.05).
Table 1. Genotype and allele frequencies for the FTO-SNPs rs , rs and rs FTO, -108CT-PON in obese and non-obese children from Yucatán, Mexico.
OBJECTIVE
To evaluate the association of the FTO-SNPs (rs , rs , rs ) and their haplotypes with the genetic risk for obesity in children from Yucatán, México.
MATERIALS Y METHODS
Design:
Case-control
association study
Anthropometric parameters:
Waist circunference
BMI
Waist/height index
Birth weight :
DNA isolation
Genotyping of SNPs:
Real time PCR
Taqman probes
Estimations:
Genotype frequencies
Allele frequencies
Hardy-Weinberg expectations
Statistical analysis: STATA.
x2 (Fisher exact)
Odds ratio (IC 95%),
Logistic regression
Cases:
211 obese children
BMI Pc < 95
Controls:
204 Non-obese
children
BMI Pc > 95
CONCLUSION
The heterozygous genotype of the SNPs rs , rs , and rs , as well as the allele C of rs in the FTO gene contribute significantly to the genetic risk for obesity in children from Yucatán, Mexico. However, their haplotypes are not involved to the risk for children obesity in the studied population.
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Acknowledgments: Fondos sectoriales de SALUD and Thermo Fisher Scientific- Applied Biosystems de México S. De R.L. De C. V.