A mechanism for significant disruption of gene activity in autism that may be reversible has been found by researchers.
The research by scientists at The George Washington University School of Medicine and Health Sciences' Department of Biochemistry and Molecular Biology has been published in the journal Genome Medicine.
The study focuses on the differential expression of microRNA and addresses the issue of higher level regulation of gene expression in autism.
MicroRNA are recently discovered snippets of RNA (ribonucleic acid), each of which can inhibit the expression (and thus activity) of hundreds to more than a thousand genes. The effects of microRNA are also reversible by treatment with complementary "anti-sense" RNA.
Valerie Hu, Ph.D., professor of Biochemistry and Molecular Biology, with a GW graduate student and collaborators at the National Institute of Mental Health, identified changes in the profile of microRNAs between identical twins and sibling pairs, discordant for diagnosis of autism. They discovered that, despite using cells derived originally from blood, brain-specific and brain-related microRNAs were found to be differentially expressed in the autistic samples, and that these microRNAs could potentially regulate genes that control many processes known to be disrupted in autism. For example, differentially expressed microRNAs were found to regulate genes highly involved in neurological functions and disorders in addition to genes involved in gastrointestinal diseases, circadian rhythm signaling, and steroid hormone metabolism.
The study further shows that by treating the cells with "anti-sense" RNA antagonists (inhibitors) to specific microRNA or by employing mimics of a particular microRNA, one can reverse the pattern of expression of a given target gene regulated by that microRNA.