Fragile X syndrome corrected
Scientists say the breakthrough could lead to a treatment for fragile X
Thursday, 20, Dec 2007 09:20
Scientists claim to have made a breakthrough that could lead to a potential treatment of the fragile X disorder.
This disorder is the most common form of mental retardation and is a leading identified genetic cause of autism.
There is currently no treatment or therapy for the syndrome, whose symptoms include epilepsy and abnormal body growth.
In tests on mice researchers significantly alleviated a wide range of abnormalities due to fragile X syndrome by altering a single gene.
The syndrome is known to be caused by loss of the gene for fragile X mental retardation protein (FMRP), which is thought to act as a brake on protein synthesis in areas of the brain.
The researchers behind today's study published in the journal Neuron propose that loss of this 'brake' would allow another protein that stimulates this process – called metabotropic glutamate receptor 5 (mGluR5) – to function unchecked.
In experiments to test this theory, the researchers studied mice that had many characteristics of fragile X in humans due to a loss of the FMRP gene.
Other mice were created that lacked both the FMRP gene and had a 50 per cent reduction in mGluR5 (known as double mutant mice).
This reduction was found to greatly alleviate many abnormalities produced by loss of FMRP.
The double mutant mice had less abnormalities in brain structure and function, brain protein synthesis, memory and body growth.
They also showed a substantial reduction in epileptic seizures caused by lack of FMRP.
"It is remarkable that by reducing mGluR5 gene dosage by 50 per cent we were able to bring multiple, widely varied fragile X phenotypes significantly closer to normal," the researchers conclude.
They add that their findings "have major therapeutic implications for fragile X syndrome and autism".