TCF7L2 and metabolic syndrome: In a systematic review on the most studied SNP-MetS associations, the authors found an association with MetS for SNPs, mostly located in genes involved in lipid metabolism like FTO rs9939609, TCF7L2 rs7903146, APOA5 rs662799, APOC3 rs2854117, IL6 rs1800795, and CETP rs708272 [24].