Parent of origin effects in obesity in the Sorbs

Parent of origin effects (POE) which could explain part of heritability in obesity were studied. The candidate gene FTO (fat mass and obesity associated) was selected from the Sorbs, a selfcontained population from eastern Germany. We hypothesized there were variants within robustly replicated FTO that conferred different risk of obesity depending on the parental origins of alleles. Genotypes from 525 Sorbs individuals were phased and parental origins were assigned to the alleles by using software AlphaImpute. Subsequently, standard association tests and parent-of-origin specific association tests were applied to 22 SNPs (single nuclear polymorphism) within FTO introns 1 to 3. Indications of parental origins were identified at several SNPs. To further support our findings, parental asymmetry tests in 705 German childhood obesity trios were performed and revealed further indications for POE effects.