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Gene Mutation May Lead to Cognitive Symptoms in Parkinsonís
- Apr 10 2012
Mutations in a particular gene may lead to cognitive deficits in people with early-onset Parkinson’s disease (PD), according to new research published in the May 1 issue of the journal Neurology. The findings suggest that mutations to the gene, called GBA, are risk factors for the development of cognitive symptoms in people with Parkinson’s. Mutations in GBA are found in roughly five percent of all people with Parkinson’s, and are more common in Ashkenazi Jews, where one in four or five people with Parkinson’s are carriers a GBA mutation.
Research has shown that over 80 percent of people with Parkinson’s eventually develop cognitive symptoms as a result of the disease. However, little has been known about how such cognitive symptoms develop and why they occur in some people with Parkinson’s but not others. Research has also shown that mutations to the GBA gene are a risk factor for developing Parkinson’s, and lead to the development of Lewy bodies in the brain, which have been related to cognitive symptoms in people with PD. But no study had demonstrated a link between mutations to the GBA gene and changes in cognitive behavior.
In this study, a large team of scientists from the PDF Research Center at Columbia University Medical Center led by Roy Alcalay, M.S., M.D., studied the effects of mutations to the gene GBA on behavior. To study this, the Columbia team administered a range of behavioral and cognitive tests to people with PD, some of whom had mutations to the GBA gene and some of whom did not.
- Of 147 total people with Parkinson’s that were enrolled in the study, 33 had mutations in the GBA gene. To age match the two groups, researchers studied a final group that included 33 people with GBA mutations and 39 non-carriers of such mutations.
- There were no differences in demographic details such as age, gender, or education between the two groups.
- People with GBA mutations had lower scores on the Mini-Mental State Exam, a common test of cognitive function.
- In particular, carriers of GBA mutations performed significantly worse on tests of memory and visuospatial function than those who did not have GBA mutations.
What Does it Mean?
These results provide strong evidence that mutations to the GBA gene contribute to the development of cognitive symptoms in people with Parkinson’s. While it is likely that there are other genetic mutations and environmental factors that also contribute to cognitive decline in Parkinson’s, these findings represent an important step toward understanding this particularly concerning set of symptoms for people with Parkinson’s.
The implications of these findings are that clinicians may be able to use genetic testing to better predict the risk of cognitive problems in people with Parkinson’s. In addition, this study highlights the importance of the GBA pathway in cognitive function in people with Parkinson’s. There is currently no known treatment to aid the symptoms that result from mutations to the GBA gene. However, it is possible that treatments will be developed in the future that specifically target the pathology and symptoms of GBA mutations. Future studies – for example, testing whether interventions targeting the GBA pathway may help cognitive function in PD – are required.
The results of this study could allow for a behavioral means to determine which people with Parkinson’s are likely to benefit from such treatments.
Reference: Alcalay, R. N., Caccappolo, E., Mejia-Santana, H., Tang, M. X., Rosado, L., Orbe Reilly, M., Ruiz, D., et al. (2012). Cognitive performance of GBA mutation carriers with early-onset PD: The CORE-PD study. Neurology. doi:10.1212/WNL.0b013e318253d54b
Source Date: Apr 10 2012