Abstract: Objective: To observe the distribution of DLX2 gene polymorphism in the population with dental fluorosis caused by coal-burning pollution in Bijie city, and to explore the relationship between genetic susceptibility and tolerance of dental fluorosis and DLX2 gene polymorphism. Methods: Under a case-control study, 117 dental fluorosis patients (experimental group) and 108 non-dental fluorosis subjects (internal control group) were enrolled in Bijie city (fluorosis area), and 115 non-dental fluorosis subjects (external control group) were enrolled in Guiyang two urban areas (non-epidemic area). Their remaining peripheral blood samples after routine blood test were collected. The genomic DNA from blood samples were extracted. SNP loci was screened for PCR amplification, and the amplification products were used Sanger sequencing technology to detect the single nucleotide polymorphism sites' genotypes. The differences of different genotypes and allele frequency distribution among groups were analyzed. Results: There was no significant difference in genotype and allele frequency distribution of rs743605 loci among groups (P>0.05). The frequency of CC genotype was significantly higher in severe dental fluorosis than that in mild and moderate dental fluorosis. The frequency of T allele in severe dental fluorosis was significantly lower than that in mild and moderate dental fluorosis, with difference statistically significant (P<0.05). The distribution of rs3762499 genotype was significantly different among groups (P<0.05). The AG genotype frequency in the internal control group was significantly higher than that in the experimental group (P<0.05). There was no significant difference in genotype and allele frequency distribution among mild, moderate, and severe dental fluorosis (P>0.05). Conclusion: The polymorphism of rs743605 and rs3762499 in DLX2 gene is correlated with dental fluorosis.

Key words: homeobox gene, DLX2 gene, dental fluorosis, gene polymorphism