Maternal Weight Phenotype as a Predictor of Methylation of Obesity-Related CpG Sites in Saliva Samples from Latino Children. Homo sapiens

Epigenetics presents a dynamic approach to assess complex individual variation in obesity susceptibility. However, few studies have examined epigenetic patterns in preschool-age children, despite the relevance of this developmental stage to trajectories of weight gain, because of difficulties obtaining blood tissue samples. This proof of principle study examined DNA methylation in 92 saliva samples, comparing Latino preschool children of normal weight mothers (Body Mass Index [BMI] 30 kg/m2 and WC >100 cm). We hypothesized that salivary DNA methylation patterns in Latino preschool age children born of normal weight vs obese weight mothers would be: 1) associated with maternal BMI phenotype in continuous linear regression analysis; 2) saliva could demonstrate epigenetic variation across individuals; and 3) preschool child saliva would be differentially methylated when comparing those children with obese versus normal weight mothers. One hundred and nineteen CpG sites were significantly (p-value 30 kg/m2 and WC >100 cm). Antropometry was measured objectively according to a standardized protocol.Saliva from preschool Latino children at risk for obesity (BMI>50% .99). Methylation data were quality controlled using Illumina GenomeStudio (V2011.1), Methylation module (V1.9.0). Samples with lower than 98% call rate (i.e. 1%), or any probes with p-values greater than 0.05 for more than 20% of the sample were sequentially excluded. Validation via pyrosequencing was conducted.