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TCF7L2 polymorphisms and progression to diabetes in the Diabetes Prevention Program
Jose C Florez1, Kathleen A Jablonski, Nick Bayley
1Diabetes Prevention Program Outcomes Study Coordinating Center, George Washington University, Rockville, Md 20852, USA. dppmail@biostat.bsc.gwu.edu
The New England Journal of Medicine
|July 21, 2006
Summary
Genetic variants in the transcription factor 7-like 2 gene (TCF7L2) increase type 2 diabetes risk in individuals with impaired glucose tolerance. These TCF7L2 genotypes are linked to reduced insulin secretion, not insulin resistance.
Area of Science:
- Genetics
- Metabolic Diseases
- Diabetes Research
Background:
- Transcription factor 7-like 2 (TCF7L2) gene polymorphisms are linked to type 2 diabetes.
- Specific variants (rs12255372 and rs7903146) are strongly associated with diabetes risk.
Purpose of the Study:
- To investigate if TCF7L2 variants predict type 2 diabetes progression in individuals with impaired glucose tolerance.
- To compare the predictive effect of these variants across different interventions (lifestyle, metformin, placebo).
Main Methods:
- Genotyping of TCF7L2 variants (rs12255372 and rs7903146) in 3548 participants.
- Cox regression analysis incorporating genotype, intervention, and interaction terms.
- Assessment of genotype effects on insulin secretion and sensitivity.
Main Results:
- The risk-conferring TT genotype at rs7903146 significantly increased diabetes progression risk (HR 1.55).
- The genetic effect was more pronounced in the placebo group compared to metformin or lifestyle intervention groups.
- The TT genotype was associated with decreased insulin secretion but not increased insulin resistance.
Conclusions:
- Common TCF7L2 variants are associated with increased type 2 diabetes risk in individuals with impaired glucose tolerance.
- Risk-associated TCF7L2 genotypes impair beta-cell function, specifically insulin secretion.
- The findings highlight the role of TCF7L2 in diabetes pathogenesis and suggest potential genotype-intervention interactions.
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