A significant but currently unknown number of adults with these tremor and balance problems are being diagnosed as normal aging, Parkinson's disease, senile dementia and Alzheimer's disease when their condition may be accurately and easily identified with a standard DNA blood test ordered by their doctor. The discovery is published in the Jan. 28 issue of the Journal of the American Medical Association.
Known as fragile X-associated tremor/ataxia syndrome, or FXTAS (pronounced fax-tass), the disorder affects older men who are carriers of a small mutation (premutation) in the same gene that causes fragile X syndrome, the most common cause of inherited mental retardation. Nearly 1 in 800 men in the general population carries this premutation in the fragile X gene, and UC Davis research suggests that as many as 30 percent of carriers -- roughly 1 in 3,000 men -- may develop FXTAS later in life.
"FXTAS may be one of the most common causes of tremor and balance problems in the adult population, yet it is being misdiagnosed because neurologists who see adults with movement disorders are not aware that they need to look for a family history of fragile X in grandchildren or to check for the presence of the premutation in the fragile X gene," said Randi Hagerman, medical director of the UC Davis M.I.N.D. Institute. (M.I.N.D. stands for Medical Investigation of Neurodevelopmental Disorders.)
Screening for the gene mutation in men who have tremor and balance problems is important regardless of their family history, especially when accompanied by other signs such as parkinsonism (rigidity in movement), short-term memory loss and
Contact: Carole Gan
University of California, Davis - Health System