Children with Angelman syndrome are often seen laughing and smiling, but this cheerful demeanor masks serious neurological problems mental retardation, movement problems and seizures.

New research in mice, however, suggests that many of these deficits could be alleviated.

Edwin Weeber, Ph.D., and colleagues reversed the neurological deficits in a mouse model of Angelman syndrome by preventing the inhibition of CaMKII, an enzyme highly expressed in brain regions affected by Angelman syndrome.

The results, which appear in the March issue of Nature Neuroscience (currently available online), reveal an important part of the mechanism underlying the condition and point to potential therapeutic targets for treating these symptoms.

Angelman syndrome, which affects approximately one in 15,000 children, is a debilitating neurological disorder characterized by mental retardation, severely limited speech, and movement and balance problems.

In 1997, researchers determined that Angelman syndrome was caused by a mutation in a single gene, called UBE3A. They subsequently developed a mouse model of Angelman syndrome by mutating this gene.

But the finding was baffling, said Weeber, because UBE3A is a "housekeeping" gene, meaning that it broadly regulates cellular processes not particularly specific for any of the neurological deficits seen in these children. Specifically, the protein encoded by UBE3A "tags" other proteins for degradation by the cellular "garbage disposal," the proteasome.

"The most difficult thing to rationalize was that this housekeeping gene which nobody thought did anything caused severe mental retardation," said Weeber, an assistant professor of Molecular Physiology and Biophysics and Pharmacology and senior author on the study.

"So we started trying to identify some of the protein's molecular targets."

In the process, Weeber and colleagues identified an abnor
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Contact: Melissa Marino
melissa.marino@vanderbilt.edu
615-322-4747
Vanderbilt University Medical Center
8-Feb-2007