Research article
FTO gene variation and measures of body mass in an African population
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* Corresponding author: Branwen J Hennig branwen.hennig@lshtm.ac.uk
- † Equal contributors
1 MRC International Nutrition Group, NPHIRU, EPH, London School of Hygiene & Tropical Medicine, London WC1E 7HT, UK
2 Medical Genetics Unit, Ospedale S. Pietro FBF, 00189 Rome, Italy
3 MRC Keneba, Medical Research Council Laboratories, Fajara, PO Box 273, Banjul, Gambia
4 Genetics of Complex Traits, Institute of Biomedical and Clinical Science, Peninsula Medical School, Exeter EX1 2LU, UK
5 Diabetes Genetics, Institute of Biomedical and Clinical Science, Peninsula Medical School, Exeter EX1 2LU, UK
BMC Medical Genetics 2009, 10:21 doi:10.1186/1471-2350-10-21
Published: 5 March 2009Abstract
Background
Variation in the fat mass and obesity associated (FTO) gene has been reproducibly associated with body mass index (BMI) and obesity in populations of White European origin. Data from Asians and African-Americans is less conclusive.
Methods
We assessed the effect of 16 FTO polymorphisms on body mass in a large population of predominantly lean Gambians (Nmax 2208) participating in a long-term surveillance program providing contemporary and early-life anthropometric measurements.
Results
Sixteen FTO tagSNPs screened here, including several associated with BMI in Europeans, were not associated with birth weight (BWT), early weight gain in 1–2 year olds, BMI in adults (≥ 18 y), or weight-for-height (WFH) z-score across all ages. No association was seen between genotype and WFH z-score or other measures of body mass. The confidence limits indicate that the effect size for WFH z-score never exceeded 0.17 units per allele copy for any SNP (excluding the three SNPs with allele < 15%). with much the lowest allele frequency. The confidence interval of the effect size for rs9939609 did not overlap that reported previously in Europeans.
Conclusion
To our knowledge this is the first study of FTO gene variation in a well-characterised African population. Our results suggest that FTO gene variation does not influence measures of body mass in Gambians living a traditional lifestyle, or has a smaller effect than that detected in Europeans. These findings are not directly comparable to results from previous studies in African-Americans due to differences in study design and analysis. It is also possible that any effect of FTO genotype on body mass is of limited relevance in a lean population where little excess food is available, compared to similar ethnic populations where food supply is plentiful.