A new study by researchers at The George Washington University School of Medicine and Health Sciences' Department of Biochemistry and Molecular Biology raises hope that autism may be more easily diagnosed and that its effects may be more reversible than previously thought. Researchers have identified potentially removable chemical tags (called "methyl groups") on specific genes of autistic individuals that led to gene silencing. They also observed these changes in cells derived from blood, opening the way to molecular screening for autism using a blood test.
Valerie Hu, Ph.D., professor of Biochemistry and Molecular Biology, with a GW graduate student and collaborators from the City of Hope, have identified chemical changes in DNA taken from cells of identical twins and sibling pairs, in which only one of the twins or siblings was diagnosed with autism. The researchers compared the genes that showed changes in DNA tagging (called "methylation") with a list of genes that showed different levels of expression (or gene "activity") from these same individuals. The amount of protein produced by two genes that appear on both lists in the cerebellum and frontal cortex of autistic and control subjects was studied, and the researchers found that both proteins, as predicted by the observed increase in DNA tagging, were reduced in the autistic brain.
These outcomes suggest that blocking the chemical tagging of these genes with drugs that prevent the methylation process may reverse symptoms of autism if the specific genes can be targeted, and demonstrate the feasibility of using more easily accessible cells from blood (or other non-brain tissues) for diagnostic screening.