The role of osteopontin gen polimorphism in children with nephrolithiasis

Urolithiasis is an abnormal accumulation, containing cristal components in an organic matrix, that can form any where along the urinary tract. Its? etiology is multifactorial including metabolic abnormalities, genetic susceptibility, nutritional factors, anatomic malformations of urinary tract and medical treatments facilitating urinary stone formation. Its? prevalance in childhood is 2-3 %. It is an important health problem with high morbidity and potential to cause end-stage renal failure. Incidence, localization and etiology changes depending on climatic, dietary, genetic and socioeconomic factors. Development of nephrolithiasis occurs through cristal formation, stimulated and inhibited by many factors. Qualitative and quantitative deficiencies of urinary macromolecules are associated with formation of urinary stones and plays an important role in nephrolithiasis pathogenesis. Because of its? involvement in structure of calcium stones and effects on mechanisms of renal stone formation, like nucleation, growth and aggregation phases, OPN seems to be the protein having most important role.In our study we evaluated 65 children with urinary stones and 50 healthy children with regard to role of OPN gene polymorphism in development of nephrolithiasis in children. We evaluated the polymorphisms of 240 T>C at 5th exon and 708 C>T at 6th exon on OPN-SPP1 gene. We found that 240 T>C and 708 C>T polymorphisms were coding cD80D and cA236A synonym aminoacid changes, respectively. These polymorphisms were found to be associated with development of nephrolithiasis when patient group and control group were compared. We also detected association between 240 T>C and 708 C>T polymorphisms and some characteristics of the patients like sex, family history of nephrolithiasis, consanguinity between parents, diagnosis at an early age, bilateral stones, multiple stones, type of stones, stone recurrence, and urinary metabolic risk factors.In conclusion, association between 240 T>C and 708 C>T polymorphisms in OPN gene and nephrolithiasis were detected in this study. It is thought that although these polymorphisms code for synonym aminoacid changes, so does not cause any change in protein structure, they may create their effects through promoting changes in protein levels.