August 11, 2009

Double defect prevents movement disorder

U.S. scientists have found a second brain lesion prevents dystonia in people who already have a lesion due to a genetic mutation for the movement disorder.

Researchers at the Feinstein Institute for Medical Research, Weill Cornell Medical College and the Beth Israel Medical Center used a type of magnetic resonance imaging to study the integrity of nerve pathways in the brains of 20 people with dystonia -- a disorder characterized by sustained involuntary muscle contractions.

Although all 20 patients had inherited a genetic mutation for the disorder, only 12 showed symptoms of the disease.

Along a pathway linking the brain's cerebellum to its motor cortex, the researchers found two sites that jointly determine whether a person with the mutation will show symptoms of the disorder. Those with a single lesion in that pathway developed the involuntary and debilitating movements characteristic of dystonia. Those with a second lesion did not.

When we went back and looked at those without symptoms, we saw that they had an additional lesion downstream in the portion of the pathway connecting directly to the motor cortex, the scientists said.

They report their findings in the Journal of Neuroscience.