The impact of klotho gene polymorphisms on urinary tract stone disease.

Objectives: To investigate the effect of klotho gene and β-glucuronidase activity on stone formation in patients with urinary tract stone disease (UTSD).

Methods: A total of 103 patients with UTSD and 102 controls with no specific urolithiasis history were enrolled into the study. G395A and C1818T polymorphisms of klotho gene were analyzed with PCR method. Serum levels of calcium and phosphorus and 24-h urine levels of β-glucuronidase activity, calcium and phosphorus levels were measured biochemically.

Results: A total of 103 of patients were male (50.2 %) and 102 were female (49.8 %) (p 0.945). Twenty-four-hour urine levels of calcium were significantly higher in UTSD group, whereas no difference was observed in phosphorus levels (p < 0.001, p 0.074, respectively). As for the G395A polymorphism, type of GG was significantly higher in the patient group compared to the controls (p = 0.02), while GA genotype was significantly higher in the controls (p = 0.001). There was no significant difference in F352V and C1818T polymorphism between the patient and control groups. β-glucuronidase activity was slightly lower in the patient group without significance (p 0.932).When patients with GG genotype and the rest were compared, there were no significant difference in all parameters.

Conclusions: Any polymorphism altering the function of klotho gene may result with stone formation. We found that there are more GG sequences of G395A gene in patients with UTSD. That may be a polymorphism of klotho gene which results with stone formation. Further studies with more patients should be accomplished which are combining the genetic and epigenetic factors associated with urolithiasis and klotho gene to enlighten the etiology of this disease.