A blood test may shed new light on Fragile X syndrome related disorders in women, according to a new study published online on March 25, 2015 in Neurology, the medical journal of the American Academy of Neurology. The title of the article is” Novel Methylation Markers of the Dysexecutive-Psychiatric Phenotype inFMR1 Premutation Women.” Fragile X is the most common inherited form of intellectual disability and the most frequent genetic cause of autism. Fragile X, which is caused by a mutation in a single gene on the X chromosome, affects about 1 in 4,000 men and 1 in 6,000 women. [The mutation causes the X chromosome to appear fragile upon cytogenetic examination—see photo—hence, the name.] Even more common are Fragile X carriers of a lesser change in the Fragile X gene called a premutation, occurring in 1 in 450 men and 1 in 150 women. Fragile X premutation carriers have normal intellect, but some can develop physical symptoms over time. They are also more likely to develop social anxiety and depression. In the current study, researchers compared 35 women who had the premutation to 35 women who did not have this genetic change. The participants were given tests of their brains' executive functioning skills, such as inhibition and selective attention, and rated themselves on scales for depression and social anxiety. They also had blood tests to measure the amount of methylation in the Fragile X gene. Methylation adds methyl groups to some of the DNA, which inactivates that part of the X chromosome. Methylation is one type of so-called epigenetic changes, non-DNA alterations in genes during the lifetime that affect their expression.
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