Study characterizes epigenetic signatures of autism in brain tissue

Neurons in the prefrontal cortex of individuals with autism show changes at numerous sites across the genome, according to a study being published Online First by the Archives of General Psychiatry.

Autism spectrum disorders are a group of complex illnesses with different causes and origins. Neuronal dysfunction in the and other regions of the brain could contribute to the cognitive and behavioral defects in autism, according to background information in the article. Neurons are that send and receive within the body.

Hennady P. Shulha, Ph.D., of the University of Massachusetts Medical School, Worcester, Mass., and colleagues examined the postmortem brain tissue of 16 individuals diagnosed with autism spectrum disorder (average age 17.4 years; range 2 to 60 years) and 16 controls without autism (ranging in age from less than one year to 70 years). The tissue was obtained through the Autism Tissue Program.

The study searched, on a genome-wide scale, for genes that show an abnormal epigenetic signature – specifically histone methylation. Histones are small proteins attached to the DNA that control gene expression and activity. While genetic information is encoded by the (genome's) DNA sequence, methylation and other types of histone modifications regulate genome organization and gene expression.

The study found hundreds of loci (the places genes occupy on chromosomes) across the genome affected by altered histone methylation in the brains of autistic individuals. However, only a small percentage – less than 10 percent – of the affected genes were affected by DNA mutations. It remains to be determined whether or not genetic changes elsewhere in the genome contributed to the observed epigenetic changes, or whether non-genetic factors were responsible for the disease process in some of the affected individuals.

" neurons from subjects with autism show changes in chromatin (the substance of chromosomes) structures at hundreds of loci genome-wide, revealing considerable overlap between genetic and epigenetic risk maps of developmental brain disorders," the authors conclude.

More information: Arch Gen Psychiatry. Published online Nov. 7, 2011. doi:10.1001/archgenpsychiatry.2011.151

add to favorites email to friend print save as pdf

Related Stories

Autism blurs distinctions between brain regions

Jun 03, 2011

Autism blurs the molecular differences that normally distinguish different brain regions, a new study suggests. Among more than 500 genes that are normally expressed at significantly different levels in the ...

Tiny, spontaneous gene mutations may boost autism risk

Mar 15, 2007

Tiny gene mutations, each individually rare, pose more risk for autism than had been previously thought, suggests a study funded in part by the National Institute of Mental Health, a component of the National Institutes of ...

Recommended for you

What sign language teaches us about the brain

23 hours ago

The world's leading humanoid robot, ASIMO, has recently learnt sign language. The news of this breakthrough came just as I completed Level 1 of British Sign Language (I dare say it took me longer to master signing ...

Why do men prefer nice women?

Jul 25, 2014

People's emotional reactions and desires in initial romantic encounters determine the fate of a potential relationship. Responsiveness may be one of those initial "sparks" necessary to fuel sexual desire and land a second ...

Study reveals how to be socially successful

Jul 25, 2014

Romantic, personal and professional relationships are fraught with danger, but a University of Queensland researcher has found the secret to interacting successfully with others in such settings.

User comments