TGF-β1 polymorphism may protect against diabetic retinopathy

Image: PD 

1. The +869T/C(L10P) gene polymorphism of TGF-β1 was significantly associated with decreased susceptibility to diabetic retinopathy. 

2. The -509C/T polymorphism in the TGF-β1 gene was not associated with diabetic retinopathy. 

Evidence Rating Level: 1 (Excellent)    

Study Rundown: Diabetic retinopathy (DR) is a significant concern for diabetic patients, representing the #1 cause of blindness in American adults. Currently, there is debate about the role of transforming growth factor-beta (TGF-β1) in the development of DR.  This study searched multiple databases to identify publications that evaluated correlations between polymorphisms in the TGF-β1 gene and susceptibility to DR. The authors found that 1 specific polymorphism was associated with decreased susceptibility to DR: +869T/C (L10P). This was true in both the allele model and the recessive model. Strengths of this study include the detailed search of databases as well as the strict selection and exclusion criteria. However, a limitation in this study is a small number of publications included for analysis. Nonetheless, this is the first study to link the +869T/C (L10P) polymorphism to decreased susceptibility to DR, suggesting its important future role in DR prevention.

Click to read the study in PLoS One

Relevant Reading: Association between a 27-bp variable number of tandem repeat polymorphism in intron 4 of the eNOS gene and risk for diabetic retinopathy type 2 diabetes mellitus: a meta-analysis

In-Depth [systematic review and meta-analysis]: A detailed manual/electronic search of Medline, the Cochrane Library, Embase, Web of Science, Google Scholar, CBMDisc, Chongqing VIP database, and CNKI database was performed. A total of 3 studies looking at the association between TGF-β1 gene polymorphisms and susceptibility to DR were included. All patients included in the meta-analysis were type 2 diabetics. The fixed or random effect model was used to assess for associations between polymorphisms and DR. After removal of confounders, +869T/C(L10P) polymorphism was significantly associated with decreased susceptibility to DR (OR=1.34, 95%CI=1.03-1.73 for the allele model and OR=1.70, 95%CI=1.13-2.56 for the recessive model) while no association was found between the -509C/T polymorphism and DR.

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