Assessing the Effects of 35 European-Derived BMI-Associated SNPs in Mexican Children

Objective: The prevalence of obesity in Mexico has increased at an alarming rate in both adults and children. This study was undertaken to test in Mexican children the effects of single nucleotide polymorphisms ( SNP) that have been associated with body mass index ( BMI) and obesity in Europeans. Methods: School-age children (N=1,559, 5-17 years) were recruited in Mexico City. Thirty-five SNPs with established effects on BMI and obesity were genotyped and analyzed individually and as a combined gene score (GS). Results: SNPs in FAIM2 (rs7138803), GPRC5BB (rs12444979), MTIF3 (rs4771122), TFAP2B (rs987237), TMEM18 (rs7561317), and the GS were significantly associated with BMI. The GS explained 0.9% of the variance of BMI. Also, SNPs in LRRN6C (rs10968576) and MC4R (rs17782313) were significantly associated with overweight and obesity categories, respectively. Importantly, the effect allele frequency of 26/35 SNPs (74.3%) differed significantly between Mexican children and European adults. No significant gene 3 environment or gene 3 gene interactions were detected after Bonferroni adjustment. Conclusions: Several SNPs first associated with BMI/obesity in European adults replicated well in Mexican children, and investigating differences in the distribution of effect alleles across ethnic populations may shed light on genetic susceptibilities of different populations to obesity.