Flow chart for experimental setup. GWAS: genome-wide association study; SNP: single nucleotide polymorphism; dHPLC: denaturating high performance liquid chromatography; DAPOC: Datteln Paediatric Obese Cohort (Reinehr et al. 2007); KORA: Cooperative Health Research in the Region of Augsburg (Wichmann et al. 2005); Ulm children’s study 1: Ulm Research on Metabolism, Exercise and Lifestyle in Children (Nagel et al. 2009); BEPOC: Berlin Paediatric Obese Cohort (Bau et al. 2009); Ulm children’s study 2 and 3: Ulm Paediatric Obese Cohort A and B (INSULA) (Wabitsch et al. 2004).