Further follow-up of the confirmed SNPs in a large geographically based cohort of children (ALSPAC Study, n = 4,951 children with BMI information at age 11) showed significant and directionally consistent associations between BMI and the variants near TMEM18 (P = 3.4 × 10−5), KCTD15 (P = 0.0010) and GNPDA2 (P = 0.018) (Supplementary Table 6). Comparison of extreme childhood obesity cases (n = 1,308, SCOOP-UK) to all children in the ALSPAC cohort (n = 8,369 in the full cohort) revealed an increased risk of extreme childhood obesity for the BMI-increasing alleles near TMEM18 (OR = 1.41, P = 7.9 × 10−7), GNPDA2 (OR = 1.20, P = 1.5 × 10−4) and NEGR1 (OR = 1.29, P = 2.2 × 10−7). The absense of significant associations with childhood BMI or extreme childhood obesity for the variants near MTCH2 and SH2B1 could reflect the relatively smaller sample sizes and lower statistical power of our childhood cohorts, or perhaps a differential effect of these variants on the risk of childhood and adult-onset obesity.
