Abstract
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.
Highlights
Childhood caries (ECC) is a persistent and possibly growing public health problem
We present the results of a pilot Genome-wide association studies (GWAS) of Early childhood caries (ECC), conducted in a multi-racial/ethnic sample of preschool-age children enrolled in a community-based study of childhood oral health
This pilot GWAS was conducted using DNA extracted from saliva samples collected from a multi-ethnic sample (Table 1) of 212 lowincome preschool children enrolled in the Zero-Out Early Childhood Caries (ZOE) study (UNC-Chapel Hill IRB #08-1185) previously reported by Barakat et al.[17]
Summary
Childhood caries (ECC) is a persistent and possibly growing public health problem. Dental caries results from complex interactions among acid-producing members of the biofilm, fermentable carbohydrates, and many host factors, including susceptible tooth surfaces and saliva. Numerous candidate-gene studies have since been conducted to investigate the postulated role of several hypothesized genes in caries aetiology in children and adults[13] Studies in this body of literature have largely targeted enamel development and mineralization genes, as well as genes involved in the immune response in early childhood. As reviewed by Vieira and colleagues[12], these studies have had mixed results and currently no consensus knowledge of the genetic basis of ECC exists This is not surprising, given the very small sample size of most dental caries investigations (typically up to few hundred subjects) compared to genomics studies conducted for other common diseases and traits, frequently including upwards of 50,000–100,000 participants
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