No association of the TGF-β1 gene polymorphisms with the renal progression in autosomal dominant polycystic kidney disease (ADPKD) patients

Background: Two genetic loci, PKD1 and PKD2, have been identified as being responsible for ADPKD, and PKD1 is known to be associated with a poor prognosis. However, the presence of an intrafamilial study clinical diversity suggests that there are disease-modifying loci. Because the mechanism of the renal failure in ADPKD includes a cystic growth and tubulointerstitial atrophy and fibrosis, we studied the associations between 2 polymorphisms in the TGF-beta(1) gene, which are known to be associated with chronic tubulointerstitial inflammation, and ADPKD progression in Korean patients. Patients and methods: One hundred and twenty-five individuals who had ADPKD and 47 normal control subjects were genotyped by PCR-RFLP, the T869C (Leu10Pro) variant of TGF-beta(1) gene leader sequence was discriminated with MspA1I and the G915C (Arg25Pro) variants with BglI. Statistical significances were determined using the Chi-square test. Results: The distribution of the alleles for the TGFbeta(1) Leu10Pro polymorphism in ADPKD was: T 54%, C 46%, which was similar to the Korean (56:44, p=0.887) and Western controls (65:35). In addition, no differences were found between the ESRD and the non-ESRD groups (p=0.888) or the early hypertension and the normotension groups (p=0.249). The distribution of alleles for the TGFbeta(1) Arg25Pro polymorphism showed only the GG type which was different from the Western population controls (G:C=90:10, p=0.000). Conclusions: Our results suggest that the polymorphism at Arg25Pro of TGF-beta(1) in the Korean population has an allele distribution different from that of the Western population and that the polymorphism at Leu10Pro of TGF-beta(1) has no association with the renal progression in Korean ADPKD patients.