Parkinson's disease is a devastating neurodegenerative disorder that affects more than 1.5 million Americans, according to Saint Mary's Health Care. It is a progressive disease that involves the continued death of nerve cells within the brain, leading to tremors, muscle cramps, pain and difficulty swallowing. The risk of developing Parkinson's disease is linked to both environmental and genetic factors, and a number of genes have been identified that increase an individual's risk of developing the disease.
USP24
Genes involved in the modification of a protein called ubiquitin have been identified as possible markers for Parkinson's disease. Ubiquitiin is a small protein found in all human cells, and is involved in protein degradation. Proteins are bonded to ubiquitin when they are ready to be degraded, and this promotes their degradation. A ubiquitin-related gene, called USP24, has been identified for its involvement in Parkinson's.
In a study published in the "International Journal of Clinical Chemistry" in 2010, Dr. Y. Wu found that some variations of the USP24 gene were linked to earlier onset of Parkinson's in Taiwanese patients, which other variations seemed to correlate with a decreased risk of the disease. Dr. Wu also found that the effects of variations in USP24 worked synergistically with variations in other ubiquitin-related genes to affect the onset of Parkinson's.
A blood test to check for specific variations in the USP24 gene may allow doctors to assess a patient's risk for developing Parkinson's.
Alpha-Synuclein
Another gene thought to be involved in Parkinson's disease is alpha-synuclein. Alpha-synuclein is a protein that is commonly found on the surface of certain nerve cells in the brain. It is known to interact with components of the cytoskeleton-the network of proteins that provide structure and support to brain cells. Mutations to alpha-synuclein have been linked to Parkinson's disease.
A study published in the "Journal of Biological Chemistry" in 2000 identified two common mutations to alpha-synuclein found in patients with familial Parkinson's disease. Genetic testing can be used by doctors to identify alpha-synuclein mutations in patients with a family history of Parkinson's.
PARK7
The PARK7 gene, which codes for a protein called DJ-1, has also been linked to familial Parkinson's disease. The protein product of the PARK7 gene is involved in decreasing oxidative stress in brain cells--a process in which oxygen-containing molecules lead to genetic damage and cell stress that can cause cell death. The DJ-1 protein prevents brain cell death by protecting against oxidative stress.
According to the "Genetics Home Reference," 10 PARK7 mutations have been identified as relevant to Parkinson's disease. Mutations to PARK7 may produce a truncated form of the DJ-1 protein that is dysfunctional in cells, leaving the cells more vulnerable to oxidative stress. Genetic testing to look for mutations to PARK7 may allow doctors to identify patients with a high risk of developing Parkinson's disease.
References
- Saint Mary's Health Care: Parkinson's Disease Facts
- National Institutes of Health: Ubiquitin specific proteases USP24 and USP40 and ubiquitin thiolesterase UCHL1 polymorphisms have synergic effect on the risk of Parkinson's disease among Taiwanese.
- National Institutes of Health: Membrane association and protein conformation of alpha-synuclein in intact neurons. Effect of Parkinson's disease-linked mutations.
- "Genetics Home Reference": PARK7
