BACKGROUND: Fragile X syndrome (FSX) is the most common genetic cause of mental impairment. The syndrome is caused by alterations in the FMR1 gene found on the X chromosome. FSX affects individuals in different ways and can vary from learning disabilities to other more severe intellectual impairments. FSX can also affect physical features and speech and language development. While some patients with fragile X may bear great challenges, the impact on others is so minimal they are never diagnosed.
Males and females may also be impacted differently. Generally, females with fragile X have less severe characteristics than males. Experts attribute this difference to the fact that females have two X chromosomes while males carry just one. Therefore, females have a healthy X chromosome to make up for the one with the nonfunctioning FMR1 gene. It appears that females have the ability to create almost enough fragile X mental retardation protein (FMRP) that the body naturally needs.
THE AUTISM LINK: FSX is the most common cause of autistic behavior, however not all children with the condition have autism or an autism spectrum disorder (ASD). Roughly one-third of all FSX children exhibit some degree of autism. Approximately 2 to 6 percent of all children with autism have the fragile X gene mutation.
LATE ONSET FRAGILE X: Older male carriers of the fragile X gene may suffer from fragile X-associated tremor/ataxia syndrome (FXTAS), which can cause tremors as well as issues with balance and memory. FXTAS is often misdiagnosed as Parkinson's disease. Female carriers of the gene may suffer from problems with ovarian function. The condition fragile X-associated primary ovarian insufficiency (FXPOI) can cause infertility and early menopause.
NEWBORN SCREENING: For the first time, a blood test exists that can identify the fragile X mutation using just a few drops of blood. The test was developed by University of California, Davis researchers and studied at Rush University Medical Center in Chicago. All newborns born at the two facilities whose parents have consented will be tested for fragile X at birth using the new screening method. The goal is to screen as many as 30,000 infants over the next five years. Experts say the test may pave the way for early identification and intervention for all children with fragile X.
The new test costs just a few dollars while current tests range in the hundreds. Results can also be achieved in a few days, versus several weeks. The test works by utilizing a polymerase chain reaction (PCR) technique that amplifies the expansion of the FMR1 gene. Researchers can identify the amount of nucleotide repeats, from the normal number of repeats (generally up to 55 repeats) to the full fragile X mutation of 200 repeats or more.
FOR MORE INFORMATION, PLEASE CONTACT:
Deborah Song, Media Relations
Rush University Medical Center
Chicago, IL
(312) 942-0588
deb_song@rush.edu
http://www.fragilex.org
