The TGF-beta 1 gene codon 10 polymorphism contributes to the genetic predisposition to nephropathy in Type 1 diabetes

Aims We hypothesize that transforming growth factor-beta (TGF-beta), a multifunctional growth factor which plays a key role in the development of tissue fibrosis, may be involved in the pathophysiology of diabetic nephropathy. Our aim was to examine three polymorphisms within the TGF-beta1 gene, in codons 10, 25 and 263, for association with nephropathy in Type 1 diabetes. Methods We conducted a large case-control study using cases with Type 1 diabetes and clinical nephropathy. Controls were Type 1 diabetic subjects who have been injecting insulin for at least 50 years and have extremely low risk of nephropathy. Genotyping was by polymerase chain reaction with sequence-specific primers. Results There was a significant difference in the frequency of the TGF-beta1 codon 10 genotypes in the diabetic nephropathy group (n = 420) when compared with the controls (n = 410, P = 0.007). There were no significant differences when the frequencies of the TGF-beta1 codons 25 and 263 genotypes in the diabetic nephropathy group were compared with the control group. Conclusions In our study the TGF-beta1 codon 10 polymorphism is associated with nephropathy in Type 1 diabetes and variation in this gene may contribute to the genetic predisposition to this complication in Type 1 diabetes.