Shakhssalim et al. 2014 studied different SNPs in the CALCR (calcitonin receptor) gene and found significantly higher urine calcium concentrations for hetero- or homozygotes (patients with T allele) compared with the wild type for the 3′UTR + 18C > T polymorphism in kidney stone formers (calcium urinary stones) [47]. Here, CALCR is linked to nephrolithiasis.