Study Charts Epigenetic Landscape of Autism Brains

In the brains of individuals with autism, chemical changes to histones, proteins entwined with DNA, tend to show up near genes linked to the disorder, according to a study of postmortem brains published 7 November in the Archives of General Psychiatry.In the nucleus of every cell, threads of DNA wrap tightly around spools of histones. Methyl and other chemical groups that attach to either the DNA or histones can turn genes on or off. These so-called epigenetic changes add an extra layer of genetic control by tweaking the amount of RNA and protein produced without changing the underlying DNA sequence.Looking at postmortem brain tissue from 16 individuals with autism and 10 age-matched controls, the researchers found hundreds of places in the genome where histone methylation is different in individuals with autism.Many of these abnormal epigenetic marks land on or near known autism risk genes, suggesting that the biological pathways involving these genes may be important even in children with autism who do not carry mutations in the genes, the researchers say."You could say that the epigenetic risk architecture that’s described is tracking the genetic risk architecture," says lead investigator Schahram Akbarian, professor of psychiatry at the University of Massachusetts Medical School.Read more at...SFARI, December 2011.