Identification of new DNA methylation markers associated with obesity in children.

Background: The epigenome may represent a link between environmental factors and the genome in determining obesity risk. Alterations in the methylation pattern in DNA can affect gene expression. Therefore, the objective of this study was to evaluate global DNA methylation in children who develop obesity, establishing a comparison between them according to birth weight.

Methods: Sixteen children from a pediatric endocrinology outpatient clinic were analyzed and categorized into four groups of four children each: children with obesity born with low birth weight (GI), children with obesity born with normal birth weight (GII), children born with low birth weight but without current obesity (GIII), and a healthy control group (GIV). DNA methylation profiles were evaluated.

Results: A total of 521 DMRs (Differentially Methylated Regions) associated with childhood obesity were identified. When examining their association with birth weight, evidence of both hypermethylation and hypomethylation was found in 38 DMRs (p < 0.05). In the comparison between groups, four CpG sites are hypomethylated in the gene bodies of DBH, ARHGAP17 and PPP2R5C. Six CpG sites are hypermethylated in the bodies of TYRO3, SMYD3, ZNF117, MTF2, SETBP1 and SPG21.

Conclusion: Our results identify novel differentially methylated DNA sites associated with childhood obesity, as revealed through an epigenome-wide association study. These findings contribute to the growing body of knowledge on the epigenetic landscape of childhood obesity. In this study, new differentially methylated CpG sites were found in the gene bodies of DBH, TYRO3, and SMYD3 between children with obesity born with low birth weight and healthy children.