The relationship between Alu I polymorphisms in the calcitonin receptor gene and fluorosis endemic to Chongqing, China.
OBJECTIVE
This study explored the association between an Alu I polymorphism at position 1,377 of the calcitonin receptor (CTR) gene and endemic fluorosis.


METHODS
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.


RESULTS
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 (χ(2) = 12.317, υ = 4, p = 0.015). Allele frequencies of CTR genotypes differed significantly among the groups (χ(2) = 8.859, υ = 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.


CONCLUSIONS
An association between fluorosis and the Alu I polymorphism in the CTR gene was observed in fluoride-exposed populations.
Department of Epidemiology, Faculty of Public Health and Management, Chongqing Medical University, Chongqing, PR China.
Miao
M
Jiang
Lihong
L
Mu
Yingxiong
Y
Wang
Wei
W
Yan
Yongzhuo
Y
Jiao
D000328:Adult; D020087:Alu Elements / Q000235:genetics*; D016022:Case-Control Studies; D002648:Child; D002681:China; D005260:Female; D005459:Fluorides / Q000009:adverse effects; D009050:Fluorosis, Dental / Q000175:diagnosis / Q000209:etiology / Q000235:genetics*; D005838:Genotype; D006801:Humans; D008297:Male; D008875:Middle Aged; D016133:Polymerase Chain Reaction; D011110:Polymorphism, Genetic; D018003:Receptors, Calcitonin / Q000235:genetics*
D018003:Receptors, Calcitonin; D005459:Fluorides