Gene engineering corrects Fragile X in mice

By Maggie Fox, Health and Science Editor

WASHINGTON (Reuters) - Genetic engineering can correct the worst symptoms in mice of 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.

Fragile X syndrome affects 90,000 to 100,000 Americans. It is caused by a mutation in a gene on the X chromosome that prevents activation, or expression, of a protein called fragile X mental retardation protein or FMRP.

There is no treatment.

Mice have the same symptoms when they are bred to have a faulty version of this gene.

Howard Hughes Medical Institute 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.