A Study On The Relationship Between Vitamin D Receptor Gene Polymorphisms And The Susceptibility To Children's Dental Fluorosis Of Huainan

Dental Fluorosis(DF),also named mottled enamel,is a especial enamel hypoplasia which is caused by the lesion of ameloblasts due to long-term ingestion of high amounts of fluoride when enamel is developing. DF,the early indic of endemic fluorosis,is epidemic in the different areas. Recent researches indicate that individual susceptibility plays an important role in the development of DF.People carrying different genetypes may take an unequal sensitivity to the fluoride.Children between 8 and 12 years old in this study were chose from GuanDian countyside of FengTai county,the city of HuaiNan,which located at the north central region of AnHui province.The purposes of this study are to get the message of DF incidence about these children and to investigate the association of polymorphisms of vitamin D receptor gene(VDR) and children's dental fluorosis,so as to use the fluoride reasonably.Objective To observe the DF incidence of children in GuanDian countyside; To observe the distribution of VDR gene polymorphisms in children of Han Nationality an- d the relationship between VDR gene polymorphisms and the susceptibility to children's dental fluorosis of Han nationality.Methods Children between 8 and 12 years old with or without DF were diagnosed by Dean's method,then calculated the DF prevalence rate and dental fluorosis index(DFI); A case-control study was conducted among children with (n=101) and without(n=102) dental fluorosis in GuanDian countyside of FengTai county. DNA was extracted from blood samples of these children.The ApaI, BsmI, FokI and TaqI polymorphisms in the VDR gene were genotyped using polymerase chain reaction-restriction fragment length-polymorphism(PCR-RFLP),and Cdx2 polymorphisms were analyzed using allel- e-specific multiplex PCR(ASM-PCR).The distribution of the genotypes in patients and the control group were analyzed.Results 1. The children's DF prevalence rate of GuanDian countyside of FengTai county is 61.7%,and the DFI is 1.30.2. Different genotypes of the VDR gene existed in children of Han Nationality with the hihest distribution frequency of Aa,bb,Ff,TT, GG, which was 51.7%,89.7%,52.7%,93.1 %,51.7% respectively.Genotype Distribution frequency of aa,Bb,FF,Tt,AG was 39.9%, 7.9%,31.5%,6.9%,27.2% respectively,which came the secondly. AA,BB,ff,tt, AA(Cdx2) distribution frequency was the lowest as follows, 8.4%,2.4%,5.8%,0.0%,21.2%. But there were no significant differences in the genotypes distribution of VDR ApaI, BsmI, FokI,TaqI and Cdx2 between the controls and dental fluorosis patients(P >0.05).Conclusions 1. The level of DF incidence in GuanDian countyside of FengTai county is moderate.Measures must be taken to meet the situation.2. Different genotypes of the VDR gene existed in children of Han Nationality,and its distribution varies among different areas and races.3. There were no correlation between VDR ApaI,BsmI,FokI,TaqI,Cdx2 gene polymorp- hisms and children's dental fluorosis of Han Nationality in this area.