Possible association of amelogenin to high caries experience in a Guatemalan-Mayan population

Abstract

There is evidence for a genetic component in caries susceptibility, but the disease is greatly influenced by environmental factors, which are extremely difficult to control in humans. For the present study, we used DNA samples collected from 110 unrelated, non-cleft individuals older than 12 years of age from Tiquisate, Guatemala: a population with similar cultural, dietary and hygiene habits, similar access to the dentist and fluoride exposure. Forty-four individuals were designated 'very low caries experience' (DMFT < or = 2), and 66 were designated 'higher caries experience' (DMFT > or = 3). Single-nucleotide polymorphism markers were genotyped in selected candidate genes (ameloblastin, amelogenin, enamelin, tuftelin-1, and tuftelin interacting protein 11) that influence enamel formation. Having at least one copy of the rare amelogenin marker allele was associated with increased age-adjusted caries experience. This association was stronger in individuals with higher DMFT (DMFT > or = 20; p = 0.0000001). Our results suggest that variation in amelogenin may contribute to caries susceptibility in the population studied. The approach of comparing individuals with extremely distinct caries experiences could be valuable for decreasing the potential influence of environmental factors on genetic studies of caries.

Fig. 1.

Linear regression results comparing individuals with low caries experience (DMFT scores up to 2) versus individuals with increasing caries experience. -log linear p values plotted against DMFT cutoff. The tuftelin-1 rs2337360 marker showed significant p values for DMFT ≥ 3 up to ≥ 6. The amelogenin marker studied showed borderline significant results for DMFT ≥ 15 and highly significant results for DMFT ≥ 20.

Fig. 2.

Linear regression results comparing caries-free individuals versus individuals with increasing caries experience. -log linear p values plotted against DMFT cutoff. The amelogenin marker studied consistently showed significant/borderline results for DMFT ≥ 4 with highly significant results from DMFT ≥ 10 to DMFT ≥ 20.