Fragile X Syndrome and Autism

Neuron Image Credit: Cell Image Library

Researchers from the Washington University School of Medicine in St. Louis have identified the method by which fragile X syndrome alters signals between neurons in the brain. Fragile X syndrome is the result of a sex chromosome mutation on the X chromosome. The Fmr1 gene, located on the X chromosome, undergoes mutations that can result in inherited forms of autism, mental retardation, epilepsy, and developmental delays. According to the study, fragile X syndrome causes too many brain signals to be sent at once. This makes it more difficult for the brain to distinguish the important signals from the unnecessary signals.

The researchers discovered that the mutated Fmr1 gene causes neuronal axons to increase the amount of neurotransmitters released in the brain. According to senior author of the study, Vitaly Klyachko, "The axons are putting out much more neurotransmitter than they should, and we think this confuses the system and overloads the circuitry." The researchers contend that understanding how the signaling process in fragile X syndrome is altered is important to the development of new treatments for autism and other fragile X syndrome disorders.

Learn more about this study, see:

• Fragile X Makes Brain Cells Talk Too Much (Science Daily)