NEW YORK (Reuters Health) - Autism may be brought about by epigenetic as well as genetic factors, researchers propose in the September 8th online edition of the American Journal of Medical Genetics.
“This model,” senior investigator Dr. Arthur L. Beaudet told Reuters Health, “represents a relatively novel perspective on autism with a focus on epigenetic in addition to genetic changes and on the fact that these changes may be new in the child rather than inherited -- similar to what occurs in the case of Down syndrome.”
Dr. Beaudet of Baylor College of Medicine, Houston, Texas and colleagues hypothesize that some of the predisposing genetic factors are inherited and others occur de novo.
This is in line with findings in twins. Autism concordance is much higher (60% and more) in monozygotic twins, than in dizygotic twins (3%).
Two or more principal genes may be implicated, according to the team, and the Angelman gene (UBE3A) appears to play a role.
In fact, 1 of 17 brain samples from autopsies of patients with autism showed an epigenetic abnormality of DNA methylation at the site of this gene.
The contribution of UBE3A may be “quantitatively modest” say the investigators, but interacting proteins could result in a larger role. Moreover, environmental factors could also affect the risk new imprinting defects.
The researchers stress that they have not proved the validity of their model in autism. However, they conclude that these and other findings suggest that “the hypothesis deserves further testing.”
Source: Am J Med Genet 2004. [ Google search on this article ]
MeSH Headings:Biological Sciences: Biology: Gene Expression Regulation: Genetics: Genetics, Biochemical: Molecular Biology: Biological SciencesCopyright © 2002 Reuters Limited. All rights reserved. Republication or redistribution of Reuters content, including by framing or similar means, is expressly prohibited without the prior written consent of Reuters. Reuters shall not be liable for any errors or delays in the content, or for any actions taken in reliance thereon. Reuters and the Reuters sphere logo are registered trademarks and trademarks of the Reuters group of companies around the world.
