(LOS ANGELES) -- Parkinson's disease, often associated with boxer Muhammad Ali and actor Michael J. Fox, affects one million Americans, according to the National Parkinson Foundation.
While the exact causes largely remain a mystery, doctors know that the condition arises from the degeneration of a specific area of the brain involved in movement. As a result, those with Parkinson's experience tremors, rigidity, slowness in moving, and difficulty with balancing and walking. The disease eventually leads to mood disorders and dementia.
Not only is there no cure for Parkinson's, but many patients have no way of knowing how quickly their symptoms will progress. However, a new study from UCLA may help.
Researchers have found two variants on a gene already known to be associated with Parkinson's that may be able to predict how quickly patients with the condition will deteriorate. The study found that patients with one particular variant were four times as likely to have rapid decline of motor function. Those patients having both of the variants studied were even more likely to see their disease progress more quickly.
The information is important, as patients who have more severe motor disease tend to die sooner.
Dr. Beate Ritz, vice chair of epidemiology at UCLA and the neurologist who conducted the study, stated that up to now, there has been no way to gather this information from a patient's genes. Finding the telltale signs of a faster decline, she said, helps doctors in "identifying patients who will most benefit from early interventions."
Ritz's study observed 233 patients in California for an average of more than five years -- making it the largest study of its kind on Parkinson's disease motor symptoms to date.
Dr. Puneet Opal, an expert in movement disorders at Northwestern University's Feinberg School of Medicine, said the study poses an interesting idea, at least in terms of the basic mechanism of the disease. However, he said he doesn't believe it will change the management of Parkinson's patients very much.
"If I knew that my patient had one of these genetic variants, I wouldn't treat him any differently than my other Parkinson's patients," he said. The next step, Opal said, would be to figure out exactly how the brain is damaged by Parkinson's disease.
Copyright 2012 ABC News Radio