Variation in the number of CGG repeats in the FMR1 gene at the bottom of the X chromosome can lead to increased levels of mRNA or decreased levels of protein—both conditions that cause disease.
Fragile X syndrome is caused by an expansion of CGG nucleotide repeats in the FMR1 gene at the end of the long arms of the X chromosome. To identify the mutation, researchers culture cells in media deficient in folic acid, which causes the ends of the X chromosome to appear as though they are about to break off. Before molecular testing, this was the only way to see the mutation.
The FMR1 gene encodes the fragile X mental retardation protein (FMRP), which regulates gene expression and protein translation in the brain. FMRP is important for maintaining synaptic plasticity and the ability to make new neurons. Levels of FMRP associated with disease severity in patients with FXS.
The Fragile X Mutation the scientist staff Fragile X syndrome is caused by an expansion of CGG nucleotide repeats in the FMR1 gene at the end of the long arms of the X... |
Randi Hagerman is a Distinguished Professor of Pediatrics at the MIND Institute and Department of Pediatrics, University of California, Davis, Medical Center, Sacramento.
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