WASHINGTON (Reuters) - Genetic engineering can correct the worst symptoms in mice with Fragile X syndrome, the most common inherited cause of mental retardation and autism, U.S. researchers reported on Wednesday.
By Maggie Fox
WASHINGTON (Reuters) - Genetic engineering can correct the worst symptoms in mice with Fragile X syndrome, the most common inherited cause of mental retardation and autism, U.S. researchers reported on Wednesday.
They said it is possible a drug could do the same thing as their gene tinkering, perhaps providing a treatment for Fragile X syndrome and other causes of retardation and autism, too.
Fragile X causes seizures, impaired memory, learning disabilities, hyperactivity, severe mental retardation and accelerated body growth.
!ADVERTISEMENT!Fragile X syndrome affects 90,000 to 100,000 Americans. There is no treatment.
Investigator Mark Bear at the Massachusetts Institute of Technology and colleagues created this mutation in mice, and corrected their symptoms by adding a few more genetic tweaks.
Writing in the journal Neuron, they said an experimental class of drugs could have the same effect.
Bear said the findings support the theory that many of the symptoms of Fragile X stem from too much activation of one of the brain's chief network managers, a protein called the metabotropic glutamate receptor or mGluR5.
FMRP and mGluR5 control one another and when a mutation cuts out FMRP, mGluR5 signals run rampant.
"All these excesses can be reduced by reducing mGluR5," Bear said in a statement.
Turning off mGluR5 completely can be disastrous, so Bear's team just cut its effects in half by cross-breeding mice with mutations in FMRP with mice that had mutated mGluR5.
The resulting mice had toned-down mGluR5 and better brain development and memory, normal body growth and fewer seizures.
"Insights gained by this study suggest novel therapeutic approaches, not only for Fragile X but also for autism and mental retardation of unknown origin," Bear said.
Bear's team has experimented with a drug called MPEP, which teams of researchers have been testing for a variety of conditions, including drug addiction and anxiety. It interferes with mGluR5.
"Although not yet approved as human therapeutics, mGluR5 antagonists are currently entering into clinical trials for a broad range of psychiatric indications, including Fragile X syndrome," Bear's team wrote.
