Analysis of Polymorphisms in Genes Differentially Expressed in the Enamel of Mice with Different Genetic Susceptibilities to Dental Fluorosis

Abstract

Genes expressed during amelogenesis are candidates to increase the risk of dental fluorosis (DF). Thus, this study aimed to evaluate the association between polymorphisms in enamel development genes and susceptibility to DF in mice. Mice of both sexes, representing strains 129P3/J (n = 20; resistant to DF) and A/J (n = 20; susceptible to DF), were divided into 2 groups. Each strain received a diet with a low concentration of fluoride (F) and drinking water containing 0 or 50 mg/L of F for 6 weeks. Clinical evaluation and analysis of Vickers enamel microhardness of the incisors were performed. Livers were collected for genomic DNA extraction. Seventeen genetic polymorphisms in Amelx, Ambn, Ambn, Col14a1, Col1a1, Col5a2, Enam, Fam20a, Fam83h, Foxo1, Klk4, Mmp20, Serpinf1, Serpinh1, Smad3, Tuft1, and Wdr72 were genotyped by real-time PCR using Taqman chemistry. Overrepresentation of alleles and genotypes in DF was evaluated using the χ2 test with an alpha of 5%. The clinical aspects of the enamel and the surface enamel microhardness confirmed the DF condition. In the polymorphisms rs29569969, rs13482592, and rs13480057 in Ambn, Col14a1, and Mmp20, respectively, genotype and allele distributions were statistically significantly different between A/J and 129P3/J strains (p < 0.05). In conclusion, polymorphisms in Ambn, Col14a1, and Mmp20 are associated with the susceptibility to DF.