WORCESTER, MA In a biological quirk that promises to provide researchers with a new approach for studying and potentially treating Fragile X syndrome, scientists at the University of Massachusetts Medical School (UMMS) have shown that knocking out a gene important for messenger RNA (mRNA) translation in neurons restores memory deficits and reduces behavioral symptoms in a mouse model of a prevalent human neurological disease. These results, published today in Nature Medicine, suggest that the prime cause of the Fragile X syndrome may be a translational imbalance that results in elevated protein production in the brain. Restoration of this balance may be necessary for normal neurological function.
"Biology works in strange ways," said Joel Richter, PhD, professor of molecular medicine at UMMS and senior author on the study. "We corrected one genetic mutation with another, which in effect showed that two wrongs make a right. Mutations in each gene result in impaired brain function, but in our studies, we found that mutations in both genes result in normal brain function. This sounds counter-intuitive, but in this case that seems to be what has happened."
Fragile X syndrome, the most common form of inherited mental retardation and the most frequent single-gene cause of autism, is a genetic condition resulting from a CGG repeat expansion in the DNA sequence of the Fragile X (Fmr1) gene required for normal neurological development. People with Fragile X suffer from intellectual disability as well as behavioral and learning challenges. Depending on the length of the CGG repeat, intellectual disabilities can range from mild to severe.
While scientists have identified the genetic mutation that causes Fragile X, on a molecular level they still don't know much about how the disease works or what precisely goes wrong in the brain as a result. What is known is that the Fmr1 gene codes for the Fragile X protein (FMRP). This protein proba
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University of Massachusetts Medical School