Men's Health

Movement Disorder Linked to Faulty Gene

Jan. 27, 2004 -- Men may be carrying a genetic mutation responsible for a significant portion of the movement and mental difficulties they encounter as they grow older.

A new study suggests that this genetic abnormality only becomes apparent in men over 50 and can cause tremors, balance problems, and dementia that become more severe with age.

Researchers say many of the adults that suffer from this disorder, known as fragile X-associated tremor/ataxia syndrome (FXTAS), are misdiagnosed with other age-related conditions such as Parkinson's and Alzheimer's disease.

"FXTAS may be one of the most common causes of tremor and balance problems in the adult population, yet 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 permutation in the fragile X gene," says researcher Randi Hagerman, MD, medical director of the University of California, Davis MIND Institute, in a news release.

What Is FXTAS?

FXTAS affects older men who carry a small mutation in the same gene that causes fragile X syndrome, which is the most common cause of inherited mental retardation.

In the study, published in the Jan. 28 issue of The Journal of the American Medical Association, researchers looked at the prevalence of tremor, balance disorders, and dementia among 192 families belonging to the Northern or Southern California Fragile X Associations.

Researchers say nearly one in 800 men have this mutation in the fragile X gene, and the study suggests that as many as 30% of these men may develop FXTAS later in life.

The study showed that 17% of the men in their 50s had the disorder, but the percentage of men with symptoms, such as tremors and balance problems, increased dramatically with each decade of life. For example, 38% of the men in their 60s, 47% of those in their 70s, and 75% of men in their 80s had these symptoms.

Researchers say the majority of men with the genetic mutation will develop at least mild symptoms of FXTAS.

Initial signs of the disorder in men may include difficulty writing, walking, and using eating utensils and become more severe with age. Other symptoms may include short-term memory loss, anxiety, loss of sensation, and muscle weakness.

"FXTAS is an enigma," says Hagerman. "The disorder appears later in life in men who are generally healthy throughout childhood and early-to-mid-adulthood and have normal to above-normal intelligence, yet is caused by a defect in a gene known to cause mental retardation usually diagnosed in childhood."

Genetic Screening Urged

Researchers say the results show that screening for the genetic mutation in the fragile X gene in men is important, especially if the person is experiencing other symptoms of the disorder.

Counseling families of persons with the genetic mutation could also help inform future generations who might inherit the defect.

Studies are under way to determine which drugs might be most effective in relieving FXTAS-related symptoms.