Wednesday, September 17, 2014

New clues connect altered patterns of DNA tags to autism

Two new studies reveal changes in DNA methylation, a subtype of epigenetic modification, in autism and explore theories about where such alterations originate, whether in the womb or in sperm prior to fertilization. The first, published 2 September in Translational Psychiatry, shows that methyl groups are distributed differently in postmortem brains from people with autism than in control brains. Other studies have found altered methylation patterns in postmortem brains from people with autism, as well in their blood and cheek cells. The new study finds evidence of changes in new brain regions and genes. The researchers looked at methylation in the postmortem brains of 13 people who had autism and 12 controls. They focused on two regions in the cortex associated with atypical activity in people with autism: the prefrontal cortex and the anterior cingulate gyrus. Methylation patterns in these two regions look dramatically more similar to each other in autism brains than in control brains. This may be because the regions do not fully differentiate in autism brains, the researchers say. This finding fits with a 2011 survey of gene expression, which similarly showed fewer differences in expression patterns between brain regions in the postmortem brains of people with autism.

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