A recent study shows that researchers have altered a gene and this allowed them to correct many aspects of the fragile X syndrome in mice. They hope that the findings will offer the possibility for therapy for the syndrome.

Mark Bear, Ph.D., of the Massachusetts Institute of Technology and his colleagues stated that the X syndrome is the most common heritable form of retard and the leading cause of autism. The syndrome is caused by the loss of the gene for fragile mental retardation protein (FMRP). This study results are published by Dr. Bear and his colleagues in the December 20 issue of Neuron.

The scientists conducted a series of experiments with mice that lack the equivalent of the fragile X gene. The findings showed that FMRP acts as a brake on a second protein, mGluR5. By reapplying the brake it reduces the expression of mGluR5 and it prevents aspects of the syndrome like tendency to seizures, patterns of brain structure and function, and altered body growth.

Researchers used in their experiments four lineages of mice: wild-type mice, mice lacking FMRP but not mGluR5, mice with FMRP but lacking one of the two mGluR5 alleles, and mice without FMRP and lacking one of the two mGluR5 alleles.

Researchers concluded that "fragile X is a disorder of excess” and they believe that “these excesses can be corrected by reducing mGluR5."