Oxytocin Gene Methylation Clue to Autism
December 24, 2009
with Jasvir Singh
Scientists have found many genetic markers for autism, including evidence that malfunction of the genes that influence oxytocin receptors may be at fault. A new study by Duke Department of Medicine researcher Simon Gregory identified a different culprit: epigenetics.
We used to think of genes as a deck of cards, shuffled at conception, that determined our physical development. If you had the genes for blue eyes, your eyes were blue. But now, we know that genes may switched on and off throughout fetal development and even throughout our lives. Even physical traits like hair color are not completely pre-determined. A group of molecules on top of our DNA, the epigenome, tells genes when to turn on or off. Epigenetics is basically a mediator between nature and nurture—it can activate some genes while inhibiting others. Once the gene is turned off epigenetically, the DNA has typically been methylated.
Most studies of the genetic basis of autism have focused on genes or missing genetic material in the DNA sequence. But a link between DNA methylation and autism has been described by Gregory in the journal BMC Medicine.
Gregory and his colleagues looked at how oxytocin relates to social interaction in those with autism disorders. They examined an oxytocin receptor gene, called OXTR, and found that 70 percent of the autistic people in a study had a methylated OXTR, in comparison to only 40 percent of those without symptoms of autism.
Those with autism often have their OXTR gene turned off, which could be why they have a greater difficulty in relating to others than those without autism.
Gregory thinks that methylation-modifying drugs might be a new area to explore for autism treatments. It seems as though finding a way to turn the oxytocin receptor gene back on might be a step in the right direction for treating autism.
Read more about Gregory's study, and other work on epigenetics, in the Washington Post.