Purpose: Evidence suggests that androgens can be involved in the pathogenesis of renal stones. This study aimed at investigating coding region polymorphisms and CAG repeats in androgen receptor (AR) and their association with active renal calcium stone disease.
Materials and methods: Male patients with calcium kidney stones (N = 106) with at least two episodes of stone recurrence or size increase during the past 5 years (ASF) were enrolled from December 2008 to April 2009. Control individuals were recruited after matching for age and gender from healthy individuals without current stone or history of stone disease. Genetic sequencing and single strand conformational polymorphism (SSCP) were used to determine AR polymorphisms in the patients and controls.
Results: Two polymorphisms were identified in the AR gene: Silent G to A polymorphism in the first exon of the AR gene and C to G polymorphism in intron 4. CAG repeats ranged from 12 to 37. The C/G polymorphism in intron 4 and CAG repeats were associated with the status of active renal calcium stone disease (all p < 0.05). The CC variant of C/G polymorphism was not observed in patients with stone disease. CAG repeats less than 20 and more than 28 were mostly observed in ASF patients (p < 0.05).
Conclusions: CAG repeats and intron 4 C/G polymorphism in the AR gene have an association with renal calcium stone disease.
Keywords: androgen receptor; etiology; nephrolithiasis; polymorphism.