Dental caries and periodontitis account for a vast burden of morbidity and healthcare spending, yet their genetic basis remains largely uncharacterized. Here, we identify self-reported dental disease proxies which have similar underlying genetic contributions to clinical disease measures and then combine these in a genome-wide association study meta-analysis, identifying 47 novel and conditionally-independent risk loci for dental caries. We show that the heritability of dental caries is enriched for conserved genomic regions and partially overlapping with a range of complex traits including smoking, education, personality traits and metabolic measures. Using cardio-metabolic traits as an example in Mendelian randomization analysis, we estimate causal relationships and provide evidence suggesting that the processes contributing to dental caries may have undesirable downstream effects on health.

Fibrin gums up the works Plasmin is an abundant plasma protease that cleaves and deactivates the clot-associated protein fibrin. Human deficiencies in plasmin and its inactive proenzyme form, plasminogen (PLG), cause severe inflammation in mucosal tissues such as the mouth and eyes. Silva et al . report that, like humans, mice lacking plasminogen accumulate extravascular fibrin and develop an oral pathology that phenocopies human ligneous periodontitis (see the Perspective by Vicanolo and Hidalgo). The excess fibrin activates neutrophils through the αMβ2 (Mac-1) integrin receptor, which triggers the production of reactive oxygen species and neutrophil extracellular traps. Additionally, certain human polymorphisms in the PLG gene were found to be associated with increased likelihood of developing periodontitis, suggesting that fibrin–neutrophil interactions may be an attractive target for future treatments of this prevalent disease. —STS

There is no agnostic GWAS evidence for the genetic control of IL-1β expression in periodontal disease. Here we report a GWAS for “high” gingival crevicular fluid IL-1β expression among 4910 European-American adults and identify association signals in the IL37 locus. rs3811046 at this locus (p = 3.3 × 10−22) is associated with severe chronic periodontitis (OR = 1.50; 95% CI = 1.12–2.00), 10-year incident tooth loss (≥3 teeth: RR = 1.33; 95% CI = 1.09–1.62) and aggressive periodontitis (OR = 1.12; 95% CI = 1.01–1.26) in an independent sample of 4927 German/Dutch adults. The minor allele at rs3811046 is associated with increased expression of IL-1β in periodontal tissue. In RAW macrophages, PBMCs and transgenic mice, the IL37 variant increases expression of IL-1β and IL-6, inducing more severe periodontal disease, while IL-37 protein production is impaired and shows reduced cleavage by caspase-1. A second variant in the IL37 locus (rs2708943, p = 4.2 × 10−7) associates with attenuated IL37 mRNA expression. Overall, we demonstrate that IL37 variants modulate the inflammatory cascade in periodontal disease.

Chronic periodontitis (CP) has a genetic component, particularly its severe forms. Evidence from genome-wide association studies (GWASs) has highlighted several potential novel loci. Here, the authors report the first GWAS of CP among a large communitybased sample of Hispanics/Latinos. The authors interrogated a quantitative trait of CP (mean interproximal clinical attachment level determined by full-mouth periodontal examinations) among 10,935 adult participants (mean age: 45 y, range: 18 to 76 y) from the Hispanic Community Health Study / Study of Latinos. Genotyping was done with a custom Illumina Omni2.5M array, and imputation to approximately 20 million single-nucleotide polymorphisms was based on the 1000 Genomes Project phase 1 reference panel. Analyses were based on linear mixed models adjusting for sex, age, study design features, ancestry, and kinship and employed a conventional P < 5 × 10 -8 statistical significance threshold. The authors identified a genome-wide significant association signal in the 1q42.2 locus (TSNAX-DISC1 noncoding RNA, lead single-nucleotide polymorphism: rs149133391, minor allele [C] frequency = 0.01, P = 7.9 × 10 -9) and 4 more loci with suggestive evidence of association (P < 5 × 10 -6 ): 1q22 (rs13373934), 5p15.33 (rs186066047), 6p22.3 (rs10456847), and 11p15.1 (rs75715012). We tested these loci for replication in independent samples of European-American (n = 4,402) and African-American (n = 908) participants of the Atherosclerosis Risk in Communities study. There was no replication among the European Americans; however, the TSNAX-DISC1 locus replicated in the African-American sample (rs149133391, minor allele frequency = 0.02, P = 9.1 × 10 -3 ), while the 1q22 locus was directionally concordant and nominally significant (rs13373934, P = 4.0 × 10 -2 ). This discovery GWAS of interproximal clinical attachment level-a measure of lifetime periodontal tissue destruction-was conducted in a large, community-based sample of Hispanic/Latinos. It identified a genome-wide significant locus that was independently replicated in an African-American population. Identifying this genetic marker offers direction for interrogation in subsequent genomic and experimental studies of CP.

ObjectiveA genetic component in early childhood caries (ECC) is theorized, but no genome‐wide investigations of ECC have been conducted. This pilot study is part of a long‐term research program aimed to: (1) determine the proportion of ECC variance attributable to the human genome and (2) identify ECC‐associated genetic loci.MethodsThe study's community‐based sample comprised 212 children (mean age=39 months; range = 30–52 months; males = 55%; Hispanic/Latino = 35%, African‐American = 32%; American Academy of Pediatric Dentistry definition of ECC prevalence = 38%). Approximately 2.4 million single nucleotide polymorphisms (SNPs) were genotyped using DNA purified from saliva. A P < 5 × 10−8 criterion was used for genome‐wide significance. SNPs with P < 5 × 10−5 were followed‐up in three independent cohorts of 921 preschool‐age children with similar ECC prevalence.Results SNPs with minor allele frequency ≥5% explained 52% (standard error = 54%) of ECC variance (one‐sided P = 0.03). Unsurprisingly, given the pilot's small sample size, no genome‐wide significant associations were found. An intergenic locus on 4q32 (rs4690994) displayed the strongest association with ECC [P = 2.3 × 10−6; odds ratio (OR) = 3.5; 95% confidence interval (CI) = 2.1–5.9]. Thirteen loci with suggestive associations were followed‐up – none showed evidence of association in the replication samples.ConclusionThis study's findings support a heritable component of ECC and demonstrate the feasibility of conducting genomics studies among preschool‐age children.