Background: The aim of this study was to investigate the correlation between the transforming growth factor (TGF)-beta1 gene -509C/T polymorphism and the susceptibility to primary nephrotic syndrome (PNS), and in particular to the severe degree of tubulointerstitial damage (TID) seen in Chinese.
Methods: Ninety-eight PNS patients and 128 normal controls were studied. The extent of tubulointerstitial changes was evaluated and patients were divided into two groups according to the severe or mild degree of TID. The TGF-beta1gene -509C/T polymorphism was detected with polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique, and the serum level of TGF-beta1 was determined by enzyme-linked immunosorbent assay (ELISA).
Results: No statistical differences in genotype or allele frequency of the TGF-beta1 gene -509C/T were found between PNS and normal subjects. However, T allele and CT + T T genotype frequency were higher in the PNS with severe TID than the mild TID and controls. Additionally, the serum concentration of TGF-beta1 was significantly higher in the PNS with severe TID group than the other two groups and in the T T genotype individuals than the CC and CT genotype individuals. A logistic regression analysis demonstrated that TGF-beta1 gene -509C/T genotype was the risk factor of TID in PNS patients [OR (odd ratio) 2.34, confidence interval (CI) 0.98-3.46, p = 0.012]. CONCLUSION. TGF-beta1 gene -509C/T polymorphism was associated with severe TID. The higher value in serum concentration of TGF-beta1 was also associated with severe TID and the T T genotype/T allele. T allele gene might be the important risk factor for susceptibility.