TCF7L2 and type 2 diabetes mellitus: Individuals homozygous for rs7903146 and rs12255372 T2D risk alleles (TT/TT) expressed 2.6-fold greater levels of TCF7L2 mRNA compared to individuals homozygous for the non-risk alleles (CC/GG, p = 0.006), although differentially spliced TCF7L2 transcripts did not differ by T2D risk-associated genotype.