DNA methylation in the placentas of typically developing and autistic children

Epigenetic perturbations in the early embryo could have later effects during development. For a disease such as autism, where a diagnosis is hard before two years of age but earlier intervention is correlated with better outcomes, finding a molecular signature of the disease at birth could have a significant impact of the quality of life. Since placenta also derives from the early embryo, is a readily-available tissue at birth, and has a unique DNA methylation pattern, we tested whether disruptions in placental DNA methylation was predictive of autism. As part of the MARBLES study, parents that already had an autistic child and were therefore at much greater risk to have another autistic child were followed as they planned another pregnancy. Biological samples were collected at birth and the children followed for several years to determine the diagnosis. “Typical” children in this study were those that did not later develop autism. MethylC-seq was performed on the placentas of 23 typical and 24 autism placentas from the MARBLES study. In addition, MethylC-seq was performed on four regions in a normal placenta to assess heterogeneity within the tissue.