Within the FTO gene, many SNPs appear to be co-inherited. The SNP showing the strongest association with body weight (i.e. body mass index, BMI) is not rs9923233, although this SNP is one of co-inherited SNPs in the FTO gene region. For more information, refer to the FTO gene or the most studied of FTO SNPs, rs9930506. [PMID 17658951][PMID 18379722] Variations in the FTO gene are associated with severe obesity in the Japanese.