Analysis of mutations in the amelogenin and the enamelin genes in severe caries in Japanese pediatric patients

Caries and periodontitis are major oral diseases, both widespread and serious. Caries is thought to be caused by multifactorial, lifestyle-related factors as well as the genetic background of the patient. However, little is known about relevant genetic factors. Since the quality and quantity of enamel plays a direct role in the susceptibility to caries, we set out our quest for genetic factors from the two proteins crucial to the formation of dental enamel: amelogenin and enamelin. We isolated genomic DNAs from lingual mucosal cells derived from healthy and caries subjects, and examined the frequency of single nucleotide polymorphisms (SNPs) by the polymerase chain reactionrestriction fragment length polymorphism (PCR-RFLP) method. We focused on the SNPs of the amelogenin gene (AMELX) at positions +287 and +522 (in both cases, a C to T substitution), and on position +2452 position of the enamelin gene (ENAM; here, too, a C to T substitution). The subjects were all of Japanese extraction, of which 67 individuals served as healthy controls and 80 patients with severe caries served as test subjects. The occurrence of the substitutions at AMELX(+287), (+522) and ENAM(+2452) were 12.2, 0.0 and 11.9% in the control group, and 2.5, 0.0 and 5.0% in the caries group, respectively. The P-values for the statistical frequency of SNPs for AMELX(+287) and ENAM(+2452) were 0.142 and 0.143, respectively. Our data suggest that there was no significant association between the SNPs of those genes and caries susceptibility in the Japanese pediatric population.