Subtle signs can help doctors predict that a person will develop Huntington's disease

Subtle signs can help doctors predict that a person will develop Huntington's disease in the next few years, according to a study published in Neurology, the scientific journal of the American Academy of Neurology.

Huntington's disease is a genetic disorder that affects movement, thinking, and some aspects of personality. There is no treatment or cure for the disease.

"These results will help us understand how and who will develop Huntington's, which is important information as potential treatments are developed," said study author Jane S. Paulsen, PhD, of the University of Iowa Roy J. and Lucille A. Carver College of Medicine in Iowa City. "Ideally, treatments will target at-risk people at or before the earliest stages of the disease, before they have any problems with thinking or movement."

The study involved 218 people in North America, Europe and Australia considered at risk for Huntington's disease because they had at least one parent with the disease. If a parent has the disease, there is a 50-percent chance that the child will develop the disease.

The participants were healthy at the beginning of the study, with normal scores on movement tests or minimal signs of movement problems. They were then followed for up to 4.5 years. Those with minimal motor problems at the beginning of the study were nearly five times more likely to be diagnosed with the disease a year and a half later than those who had no movement problems initially. They were 3.5 times more likely to be diagnosed with the disease after three years.

Researchers also tested cognitive abilities. For a verbal fluency test, they were given a letter of the alphabet and 60 seconds to say as many words as they could starting with that letter. They were also tested on how quickly they could combine thinking and movement, or "psychomotor speed," with a memory and writing task. Those who performed worse on the psychomotor test than on the verbal fluency test were twice as likely to be diagnosed with Huntington's disease a year and a half later than those whose tests scores were equivalent.