Supplementary Material for: Genetic Polymorphisms in Calcitonin Receptor Gene and Risk for Recurrent Kidney Calcium Stone Disease

Introduction: In this study the full sequence of the calcitonin receptor gene (CALCR) in a group of Iranian males suffering from recurrent calcium urinary stones was compared with that of a control group. Methods: Serum and urinary biochemistry related to urolithiasis were evaluated in 105 males diagnosed with recurrent kidney calcium stones and 101 age-matched healthy control males. The polymerase chain reaction single-strand conformation polymorphism method was used to detect new polymorphisms in the CALCR. Results: Nine polymorphisms were detected; seven were in the non-coding and two in the coding region. The T allele associated with the 3UTR+18C>T polymorphism was observed exclusively in the stone formers. The exact odds ratio for the T allele in this locus for those at risk of stone formation was 36.72 (95% CI 4.95-272.0) (p < 0.001). The mean (standard deviation) urine calcium concentration was 117 (60) mg/l in patients with the C allele and 152 (72) mg/l in those with the T allele (p = 0.03). In addition, IVS1-6T>C and IVS1insA polymorphisms in intron 1 were associated with kidney stone disease (p < 0.001). Regarding single nucleotide polymorphism 447, mean (standard deviation) of serum calcitonin levels were 16.7 (18.7) pg/ml, 10.5 (11.0) pg/ml and 9.94 (9.7) pg/ml in subjects with TT, TC and CC genotypes, respectively (p = 0.01). Conclusion: Our data indicate a potential association between 3UTR+18C>T and intron 1 polymorphisms in the CALCR and the risk of kidney stone disease.