Association of FTO polymorphisms with obesity and obesity-related outcomes in Portuguese children

PLoS One. 2013;8(1):e54370. doi: 10.1371/journal.pone.0054370. Epub 2013 Jan 14.


Background: Several studies have reported an association between single nucleotide polymorphisms in the first intron of the FTO gene and body mass index (BMI) or obesity. However, this association has not yet been studied among the Portuguese population. This study aims to assess the association of three FTO polymorphisms (rs1861868, rs1421085 and rs9939609) with obesity-related outcomes in a sample of Portuguese children.

Methods: We examined a total of 730 children, 256 normal-weight (55.9% girls), 320 overweight (45.3% girls) and 154 obese (53.2% girls), aging from 6 to 12-years-old, recruited randomly from public schools in the central region of Portugal. DNA samples were genotyped for the three polymorphisms by allelic discrimination TaqMan assay. Association of the FTO polymorphisms with several anthropometric traits was investigated. Additionally, we tested association with the risk of obesity using overweight and obese vs. normal-weight children.

Results: We found significant associations of rs9939609 and rs1421085 polymorphisms with weight, BMI, BMI Z-score, waist circumference and hip circumference, even after age and gender adjustment (p<0.05 in all traits). For rs1861868 polymorphism, marginally significant associations were obtained with weight (p = 0.081) and BMI (p = 0.096) after adjustment for age and gender. In case-control studies, both rs9939609 and rs1421085 polymorphisms were significantly associated with obesity (OR 1.97; 95% CI, 1.08-3.59; p = 0.026; OR 2.11; 95% CI, 1.17-3.81; p = 0.013, respectively) but not with overweight (p>0.05). Haplotype analyses identified two combinations (ACA and GCA) associated with a higher risk of obesity (OR 1.53; 95% CI, 1.06-2.22; p = 0.023; OR 1.73; 95% CI, 1.06-2.87; p = 0.030, respectively).

Conclusions: This study provides the first evidence for the association of FTO polymorphisms with anthropometric traits and risk of obesity in Portuguese children.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alpha-Ketoglutarate-Dependent Dioxygenase FTO
  • Body Mass Index
  • Case-Control Studies
  • Child
  • Female
  • Genotype
  • Humans
  • Male
  • Obesity / genetics*
  • Overweight / genetics
  • Polymorphism, Genetic / genetics*
  • Polymorphism, Single Nucleotide / genetics
  • Portugal
  • Proteins / genetics*


  • Proteins
  • Alpha-Ketoglutarate-Dependent Dioxygenase FTO
  • FTO protein, human

Grant support

This work was performed with the support of the Research Centre for Anthropology and Health (CIAS), University of Coimbra and FCT (PEst-OE/SADG/UI0283/2011). David Albuquerque has a PhD grant (SFRH/BD/68774/2010) from FCT. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.