TCF7L2 and type 2 diabetes mellitus: These genes are: PPARG, PPARGC1A, LEPR, TCF7L2, CLOCK, ALMS1, RAPTOR and FRAP1. PPARG, PPARGC1A, LEPR and TCF7L2 were chosen because variation in these genes has repeatedly been found to be associated with T2D risk and/or metabolic syndrome risk [41–47].