relationship between Alu I polymorphisms in the calcitonin receptor gene and fluorosis endemic to Chongqing, China

ABSTRACT

This study explored the association between an Alu I polymorphism at position 1,377 of the calcitonin receptor [CTR] gene and endemic fluorosis. A case-control study of 321 participants was conducted in regions with high fluorosis rates [Wushan and Fengjie counties] and those without high fluorosis rates [Yubei Qu county; termed nonfluorosis areas] in Chongqing, China. The participants were divided into three groups the fluorosis group [FG] from areas with high fluoride exposure [121], the nonfluorosis group [NFG] from areas with high fluoride exposure [130], and a control group [CG] from areas with no excessive fluoride exposure [70]. An Alu I polymorphism in the CTR gene was genotyped using polymerase chain reaction-restriction fragment length polymorphism analysis. The genotype distributions within each group were as follows CC 60.33% [73/121], CT 30.58% [37/121] and TT 9.09% [11/121] for the FG; CC 74.62% [97/130], CT 21.54% [28/130] and TT 3.85% [5/130] for the NFG, and CC 68.57% [48/70], CT 31.43% [22/70] and TT 0% [0/70] for the CG. Significant differences in Alu I genotypes were observed among the groups [chi[2] = 12.317, upsilon = 4, p = 0.015]. Allele frequencies of CTR genotypes differed significantly among the groups [chi[2] = 8.859, upsilon = 2, p = 0.012] C 75.62% [183/242] and T 24.38% [59/242] for the FG, C 85.38% [222/260] and T 14.62% [38/260] for the NFG, and C 84.29% [118/140] and T 15.71% [22/140] for the CG. An association between fluorosis and the Alu I polymorphism in the CTR gene was observed in fluoride-exposed populations