Role of endothelial nitric oxide synthase VNTR (intron 4 a/b) polymorphism on the progression of renal disease in autosomal dominant polycystic kidney disease

INTRODUCTION Autosomal dominant polycystic kidney disease (ADPKD) is an inherited disorder, and it is mainly associated with renal cyst formation. Several studies have also shown that these mutations regulate the physiology of epithelial tissues and determine renal cyst formation and growth in polycystic kidney disease (PKD). Nitric oxide (NO) is also considered to be an important factor involved in the deterioration of renal function. OBJECTIVES The aim of the current study is to determine the frequency of NOS3 27-bp VNTR in ADPKD patients and to investigate the role of NOS3 27-bp VNTR genotypes in the modification of progression of renal disease in ADPKD. PATIENTS AND METHODS The hypothesis was investigated by studying the South Indian population of 53 ADPKD patients and 94 unrelated healthy controls. The genotyping was performed by polymerase chain reaction and electrophoresis. Genotypes were compared between ADPKD and controls using the χ(2)-test. Univariate and multivariate logistic regression analyses were performed to assess the effect of genotypes and hypertension on the progress of chronic kidney disease (CKD). A stratified analysis was also performed to assess the evidence of the modification of hypertension-CKD relationship among VNTR genotypes. RESULTS The NOS3 4a allele frequencies were 21.3% and 13.2% respectively for controls and ADPKD groups. The NOS3 VNTR genotypes and alleles were not associated with ADPKD. The univariate analysis showed that age, hypertension and NOS3 VNTR influenced the advancement of CKD. CONCLUSION The present study confirms the significant association between the 27-bp VNTR and CKD advancement among the ADPKD patients in the South Indian population.