Testing Needed to Identify Neurologic Disorder in Men

Researchers have discovered a new, progressive neurologic disorder in men over 50, which can be diagnosed with a standard DNA blood test. Their discovery was reported in the January 28, 2004, issue of the Journal of the American Medical Association (JAMA).

The disorder results in tremors, balance problems, and dementia that become increasingly severe with age. Many of the men are currently being mistakenly diagnosed with Parkinson's disease, senile dementia, or Alzheimer's disease. The disorder is known as fragile X-associated tremor/ataxia syndrome, or FXTAS, and it is caused by a small mutation in the same gene that causes fragile X syndrome, a common cause of inherited mental retardation. Screening for the gene mutation in men who have tremor and balance problems is important, especially when accompanied by other signs such as rigidity in movement, short-term memory loss, and dementia.

Research studies are now underway to determine which medications are better suited to alleviate the disorder, and whether therapies such as surgery to disable nerve tracks may actually exacerbate balance problems. When the researchers looked at 192 individuals from families with fragile X, they found 17% in their 50s had FXTAS but the percentage increased to 38% of men in their 60s, to 47% of men in their 70s, and 75% of men in their 80s.

"The disorder appears later in life in men who are generally healthy throughout childhood and early-to-mid adulthood and have normal-to-above-average intelligence, yet is caused by a defect in a gene known to cause mental retardation usually diagnosed in early childhood,” explained Dr. Randi Hagerman, medical director of the University of California, Davis, M.I.N.D. Institute (USA).