Researchers have furthered their knowledge of the fragile X syndrome. This advancement was possible thanks to a patient with a mutation in a specific gene exhibiting some of the disorder’s symptoms.
Fragile X Syndrome is the most common known cause of inherited intellectual disability.
According to the Centers for Disease Control and Prevention, about one in 5,000 males are born with fragile X syndrome. Fragile X syndrome is most likely to affect males as the FMR1 gene is on the X chromosome. The condition can lead to severe intellectual disability, including an inability to communicate.
Those with fragile X syndrome can also experience anxiety and seizures, along with physical symptoms such as enlarged heads or flat feet. Furthermore, 1/3 of people with the disorder exhibit symptoms of autism spectrum disorders.
Usually fragile X syndrome is caused by the disabling of the fragile X mental retardation (FMR1) gene responsible for creating a protein, FMRP. FMRP is used to regulated electrical signals in the brain.
The study examined a patient that had only a single error in this gene and exhibited just two of the primary symptoms of the disorder. Therefore, researchers were able to analyze a previously unknown role for the gene.
This patient’s uniqueness allowed researcher to separate two independent functions of the fragile X protein in the brain.
The ability to find the mutation and link it to a partial set of traits allowed for the identification of a distinct function that this gene is responsible for and that is likely impaired in all people with fragile X.
The study was published in Proceedings of the National Academy of Sciences, and carried out by researchers from Washingtom University and Empry UNiveristy School of Medicine in Atlanta GA. The researchers examined genetic sequencing data for over 900 males with intellectual disabilities by not fragile X syndrome.
The goal of the study was to find mutation in the FMR1 gene that impaired FMRP but did not fully eliminate it. Only one patient was found from the sample that had abnormal FMRP, caused by a small mutation in the FMR1 gene’s DNA code.
The patient had intellectual disability and experienced seizures, but he had no physical features that were associated with fragile X syndrome, nor symptoms of autism.
Researchers replicated the mutation in the mouse brain cells and found that FMRP appeared to work normally indicating that the patient’s brain cells received signals normally, working just as they would in healthy people without the disorder.
The findings suggest that drugs recently tested as treatment for fragile X syndrome may be ineffective due to targeting receivers in the brain and not addressing higher levels of signal transmission.