title: DNA methylation analysis of the autistic brain reveals multiple dysregulated biological pathways.
abstract: Autism spectrum disorders (ASD) are a group of neurodevelopmental conditions characterized by dysfunction in social interaction, communication and stereotypic behavior. Genetic and environmental factors have been implicated in the development of ASD, but the molecular mechanisms underlying their interaction are not clear. Epigenetic modifications have been suggested as molecular mechanism that can mediate the interaction between the environment and the genome to produce adaptive or maladaptive behaviors. Here, using the Illumina 450 K methylation array we have determined the existence of many dysregulated CpGs in two cortical regions, Brodmann area 10 (BA10) and Brodmann area 24 (BA24), of individuals who had ASD. In BA10 we found a very significant enrichment for genomic areas responsible for immune functions among the hypomethylated CpGs, whereas genes related to synaptic membrane were enriched among hypermethylated CpGs. By comparing our methylome data with previously published transcriptome data, and by performing real-time PCR on selected genes that were dysregulated in our study, we show that hypomethylated genes are often overexpressed, and that there is an inverse correlation between gene expression and DNA methylation within the individuals. Among these genes there were C1Q, C3, ITGB2 (C3R), TNF-α, IRF8 and SPI1, which have recently been implicated in synaptic pruning and microglial cell specification. Finally, we determined the epigenetic dysregulation of the gene HDAC4, and we confirm that the locus encompassing C11orf21/TSPAN32 has multiple hypomethylated CpGs in the autistic brain, as previously demonstrated. Our data suggest a possible role for epigenetic processes in the etiology of ASD.
authors.affiliation: Faculty of Medicine, Bar Ilan University, Safed, Israel.
authors.forename: S
authors.initials: S
authors.lastname: Nardone
authors.affiliation: Faculty of Medicine, Bar Ilan University, Safed, Israel.
authors.forename: D Sharan
authors.initials: DS
authors.lastname: Sams
authors.affiliation: Faculty of Medicine, Bar Ilan University, Safed, Israel.
authors.forename: E
authors.initials: E
authors.lastname: Reuveni
authors.affiliation: Faculty of Medicine, Bar Ilan University, Safed, Israel.
authors.forename: D
authors.initials: D
authors.lastname: Getselter
authors.affiliation: Faculty of Medicine, Bar Ilan University, Safed, Israel.
authors.forename: O
authors.initials: O
authors.lastname: Oron
authors.affiliation: Faculty of Medicine, Bar Ilan University, Safed, Israel.
authors.forename: M
authors.initials: M
authors.lastname: Karpuj
authors.affiliation: Faculty of Medicine, Bar Ilan University, Safed, Israel.
authors.forename: E
authors.initials: E
authors.lastname: Elliott
mesh_terms: D001921:Brain / Q000473:pathology*; D002659:Child Development Disorders, Pervasive / Q000175:diagnosis / Q000235:genetics* / Q000473:pathology* / Q000523:psychology; D018899:CpG Islands; D019175:DNA Methylation / Q000235:genetics*; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation / Q000502:physiology*; D006179:Gyrus Cinguli / Q000473:pathology; D006801:Humans; D009434:Neural Pathways / Q000473:pathology*; D020411:Oligonucleotide Array Sequence Analysis; D017397:Prefrontal Cortex / Q000473:pathology; D060888:Real-Time Polymerase Chain Reaction