FTO gene and MCR4 gene variants link to body weight confirmed in TRAILS
MedWire News: Common variants in the genes FTO and MCR4 are associated with overall and abdominal adiposity and body mass index (BMI) in adolescents, show results from TRAILS (TRacking Adolescents’ Individual Lives Survey).
These findings confirm research previously reported by MedWire News linking variation in FTO and MCR4 to overweight and obesity. However, the investigators found no association between a variant of the gene INSIG2 and body weight measures.
The researchers recruited 663 girls and 612 boys, aged 16 years, who were participating in the TRAILS study, an ongoing Dutch prospective cohort study. Overall, 12.4% of the children were overweight, 2.7% were obese, and 4.5% had the metabolic syndrome.
The participants were genotyped for single nucleotide polymorphisms (SNPs) in FTO (rs9939609), MCR4 (rs17782313 and rs17700633), and INSIG2 (rs7566605).
Measures of weight, height, skinfold thickness, percentage body fat, waist circumference, blood pressure, glucose, insulin, lipid profile, and BMI z-scores were also taken by the researchers and compared with previous measures taken at ages 11.0 and 13.5 years.
The risk-associated A allele for the FTO SNP rs9939609 was significantly associated with increased BMI and sum of skin-fold thicknesses, following adjustment for confounders. Each copy of the A allele increased the relative risk for being overweight at age 16 years by 34%.
The MCR4 SNP rs17782313 was significantly associated with BMI, with an increase of 0.11 in BMI z-score observed per copy of the minor allele. There was also a nonsignificant trend for an association between BMI and the other MCR4 variant rs17700633. No association between the INSIG2 SNP and measures of overweight or metabolism were found by the researchers, however.
Of note, the observed associations did not differ significantly between the ages of 11 and 16 years.
“Our findings strengthen and extend the results from previous genome-wide association studies,” conclude the authors in the American Journal of Clinical Nutrition.
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By Helen Albert