WASHINGTON, Feb. 20 (Xinhua) -- The most common inherited form of mental retardation and autism, fragile X syndrome, turns some brain cells into chatterboxes, according to a U.S. study published on Wednesday in the journal Neuron.
The extra talk may make it harder for brain cells to identify and attend to important signals, potentially establishing an intriguing parallel at the cellular level to the attention problems seen in autism. The researchers say that understanding the effects of this altered signaling will be important to developing successful treatments for fragile X and autism.
"We don't know precisely how information is encoded in the brain, but we presume that some signals are important and some are noise," says senior author Vitaly Klyachko, assistant professor at Washington University School of Medicine. "Our theoretical model suggests that the changes we detected may make it much more difficult for brain cells to distinguish the important signals from the noise."
Fragile X is caused by mutations in a gene called Fmr1. This gene is found on the X chromosome, one of the two sex chromosomes. Females have two copies of that chromosome, while males only have one. As a result, males have fragile X syndrome more often than females, and the effects in males tend to be more severe.
Symptoms of fragile X include mental retardation, hyperactivity, epilepsy, impulsive behavior, and delays in the development of speech and walking. Fragile X also affects anatomy, leading to unusually large heads, flat feet, large body size and distinctive facial features. Thirty percent of fragile X patients are autistic.