Relation of Amelogenin Gene Polymorphisms to Dental Caries Among Iraqi Teenagers

Objective: To examine the relationship between dental caries and single nucleotide polymorphisms (SNPs) in AMELX gene. Methods: This study was a comparative cross- sectional study encompassing 78 adolescents (aged 13-15 years) was conducted. All of them were examined for their oral and dental status under the WHO recommended criteria, and clinical information such as DMFT and DMFS were evaluated. Individuals whose DMFT and DMFS index lower than 2 were designated 'very low caries experience' and higher than 9 were designated 'higher caries experience'. Genomic DNA was extracted from saliva samples, and single nucleotide polymorphisms of AMELX were genotyped. Genotyping of three SNPs (rs17878486, rs5933871, rs5934997, intron) in AMELX gene was determined by direct sequencing and analyzed with SNPStats. Chi-square was used to compare allele and genotype frequencies between cases and controls. Results: There was no significant difference between the high and low caries groups but in high caries group, it showed a deviation from Hardy-Weinberg equilibrium with a significant difference among the three genotypes (p=0.013) in rs5933871 and rs5934997, while a highly significant difference in rs17878486 for both high and low caries groups (p=0.000 and p=0.001). A highly significant and positive correlation between rs17878486 with DMFS in the control group and a positive significant correlation between rs17878486 and DMFT. Conclusion: Although no significant difference of the investigated SNPs of AMELX between high and low caries groups, but rs17878486 had a significant and positive correlation with DMFT and DMFS which made this SNP as marker for caries susceptibility.