Association of TCF7L2 SNPs with age at onset of type 2 diabetes and proinsulin/insulin ratio but not with glucagon-like peptide 1.

Background: Variants in TCF7L2 have been associated with the age at onset of type 2 diabetes in Mexican Americans. However, there is a lack of data on this relationship in Caucasians. Furthermore, risk alleles in TCF7L2 have been suggested to account for decreased conversion of proinsulin to insulin and decreased expression of GLP-1.