The etiology of chronic periodontitis clearly includes a heritable component. Our purpose was to perform a small exploratory genome-wide association study in adults ages 18-49 years to nominate genes associated with periodontal disease-related phenotypes for future consideration. Full-mouth periodontal pocket depth probing was performed on participants (N = 673), with affected status defined as two or more sextants with probing depths of 5.5 mm or greater. Two variations of this phenotype that differed in how missing teeth were treated were used in analysis. More than 1.2 million genetic markers across the genome were genotyped or imputed and tested for genetic association. We identified ten suggestive loci (p-value ≤ 1E-5), including genes/loci that have been previously implicated in chronic periodontitis: LAMA2, HAS2, CDH2, ESR1, and the genomic region on chromosome 14q21-22 between SOS2 and NIN. Moreover, we nominated novel loci not previously implicated in chronic periodontitis or related pathways, including the regions 3p22 near OSBPL10 (a lipid receptor implicated in hyperlipidemia), 4p15 near HSP90AB2P (a heat shock pseudogene), 11p15 near GVINP1 (a GTPase pseudogene), 14q31 near SEL1L (an intracellular transporter), and 18q12 in FHOD3 (an actin cytoskeleton regulator). Replication of these results in additional samples is needed. This is one of the first research efforts to identify genetic polymorphisms associated with chronic periodontitis-related phenotypes by the genome-wide association study approach. Though small, efforts such this are needed in order to nominate novel genes and generate new hypotheses for exploration and testing in future studies.

Epidemiological evidence supports the existence of a possible link between type II diabetes mellitus (T2DM) and late-onset Alzheimer\'s disease (LOAD). Polymorphisms from candidate genes for T2DM were genotyped in a two-stage approach to identify novel risk factors for LOAD. One hundred fifty-two polymorphisms were initially genotyped in a case:control cohort: nine SNPs showed individual association with disease status under at least one genetic model, while an additional two SNPs showed a haplotype association. In a replication study, we confirmed significant association of SNPs within three genes--PPARgamma, SOS2, and PCK1--with Alzheimer\'s disease. In particular, our data suggest that the effect of variants within these genes might be influenced by gender.