(948.18) Distribution and Allelic Frequency of the Enamelin Gene Variant rs7671281 Associated to Amelogenesis Imperfecta and High-risk Caries in Puerto Rico

Poster Board Number: E520

Limary Morales Morales (University of Puerto Rico at Mayagüez), Edwin Ramirez-Aponte (University of Puerto Rico at Mayagüez), Juan Martinez-Cruzado (University of Puerto Rico at Mayagüez)

Amelogenesis imperfecta (AI) is an inherited, rare dental disorder that affects only the formation of tooth enamel and shows both clinical and genetic heterogeneity. Similarly, the enamelin gene (ENAM) has a fundamental role in the mineralization and structural organization of enamel and any change in its sequence can affect the thickness of the enamel. The objective of this study is to be able to confirm the association between the genetic variant rs7671281 in the ENAM gene with AI and high-risk caries subjects in the Puerto Rican population. This nonsense variant has been associated with the local, autosomal dominant hypoplastic form (type IB) of AI. Through Real-time PCR, we determined the allelic frequency and geographic distribution of rs7671281 by genotyping 622 samples of healthy subjects from Puerto Rico. Due to its association with a reduction in enamel thickness, rs7671281 is also genotyped to check its role in the susceptibility to the risk of developing dental caries. The present study was carried out in the Puerto Rican population with phenotypes associated with amelogenesis imperfecta and subjects with a high to moderate prevalence of dental caries. In turn, subjects with a low to no prevalence of dental caries were considered as controls. Through the collection and analysis of saliva samples, the prevalence of the enamelin variant rs7671281 was confirmed in the Puerto Rican population. The island-wide distribution pattern is non-regionalized and influenced by coastal regions, but mostly predominated in the South and East area of the island. According to the 1000 Genomes Project, the allelic frequency of rs7671281 for the T allele was 0.885 (184) and for the C allele was 0.115 (24) based on a total of 208 samples. The present study shows a significant decrease in the allelic frequency of rs7671281 for the mutated allele C (0.0530) in comparison to the 1000 Genomes Project (0.115). Therefore, we concluded that the allelic frequencies of rs7671281 analyzed in this study are more accurate than the values given in the 1000 Genomes Project.

We thank Mr. Edwin G. Ramirez- Aponte for providing the necessary research skills and
funding as our mentor. We would like to acknowledge Dr. Juan C. Martinez-Cruzado
and the lt;igt;UPRM Population Genetics Laboratorylt;/igt; for attributing the repertoire of
DNA samples and research equipment. Also, the collaborative assistance of the
investigative group that work on the lt;igt;Study of Genetic Variants associated to Risk Factors
and Mendelian Conditions in Puerto Ricolt;/igt;.