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International Journal of Endocrinology
Volume 2013 (2013), Article ID 374858, 5 pages
Clinical Study

Association between TCF7L2 Genotype and Glycemic Control in Diabetic Patients Treated with Gliclazide

1Department of Internal Medicine 4, Faculty of Medicine, L. Pasteur University Hospital, P. J. Šafárik University in Košice, 041 90 Košice, Slovakia
2Department of Medical Biology, Faculty of Medicine, P. J. Šafárik University in Košice, 040 66 Košice, Slovakia

Received 4 December 2012; Accepted 20 January 2013

Academic Editor: Ewan Pearson

Copyright © 2013 Martin Javorský et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Previous studies showed associations between variants in TCF7L2 gene and the therapeutic response to sulfonylureas. All sulfonylureas stimulate insulin secretion by the closure of ATP-sensitive potassium ( ) channel. The aim of the present study was to compare TCF7L2 genotype specific effect of gliclazide binding to channel A-site (Group 1) with sulfonylureas binding to AB-site (Group 2). A total of 101 patients were treated with sulfonylureas for 6 months as an add-on therapy to the previous metformin treatment. TCF7L2 rs7903146 C/T genotype was identified by real-time PCR with subsequent melting curve analysis. Analyses using the dominant genetic model showed significantly higher effect of gliclazide in the CC genotype group in comparison with combined CT + TT genotype group ( % versus %, ). No significant difference in ΔHbA1c between the patients with CC genotype and the T-allele carriers was observed in Group 2. In the multivariate analysis, only the TCF7L2 genotype ( ) and the baseline HbA1c ( ) were significant predictors of ΔHbA1c. After introducing an interaction term between the TCF7L2 genotype and the sulfonylurea type into multivariate model, the interaction became a significant predictor ( ) of ΔHbA1c. The results indicate significantly higher difference in ΔHbA1c among the TCF7L2 genotypes in patients treated with gliclazide than in patients treated with glimepiride, glibenclamide, or glipizide.