- Paralysis agitans
- Parkinson's disease
- Primary parkinsonism
- Shaking palsy
Your QuestionThe woman I would like to marry has a family history of Parkinson disease. How is this condition inherited? How is it diagnosed? Is genetic testing available?
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More detailed information about the cause of Parkinson disease is available through an information page developed by the National Institute of Neurological Disorders and Stroke (NINDS). Click here to view this information.
Approximately 15 percent of people with Parkinson disease have a family history of the disorder. These familial cases are caused by mutations in the LRRK2, PARK2, PARK7, PINK1, or SNCA gene, or by alterations in genes that have not yet been identified. Mutations in some of these genes may also play a role in cases that appear to be sporadic.
It is not fully understood how mutations in the LRRK2, PARK2, PARK7, PINK1, or SNCA gene cause Parkinson disease. Some mutations appear to disturb the cell machinery that breaks down (degrades) unwanted proteins. As a result, un-degraded proteins accumulate, leading to the impairment or death of dopamine-producing neurons. Other mutations may involve mitochondria, the energy-producing structures within cells. As a byproduct of energy production, mitochondria make unstable molecules, called free radicals, that can damage the cell. Normally, the cell neutralizes free radicals, but some gene mutations may disrupt this neutralization process. As a result, free radicals may accumulate and impair or kill dopamine-producing neurons.
In some families, alterations in the GBA, SNCAIP, or UCHL1 gene appear to modify the risk of developing Parkinson disease. Researchers have identified some genetic changes that may reduce the risk of developing the disease, while other gene alterations seem to increase the risk.
The inheritance pattern is unclear when an increased risk of Parkinson disease or parkinsonism is associated with mutations in the GBA gene. SNCAIP and UCHL1 mutations have been identified in just a few individuals. It is unclear how these mutations are related to Parkinson disease, and the inheritance pattern remains unknown.
The following online resources can help you find a genetics professional in your community:
- The National Society of Genetic Counselors provides a searchable directory of US and international genetic counseling services.
- The American College of Medical Genetics has a searchable database of US genetics clinics.
- The University of Kansas Medical Center provides a list of US and international genetic centers, clinics, and departments.
- The American Society of Human Genetics maintains a database of its members, which includes individuals who live outside of the United States. Visit the link to obtain a list of the geneticists in your country, some of whom may be researchers that do not provide medical care.
- Parkinson's Disease: Hope Through Research. National Institute of Neurological Disorders and Stroke. September 30, 2011; http://www.ninds.nih.gov/disorders/parkinsons_disease/detail_parkinsons_disease.htm#127443159. Accessed 10/2/2011.
- Learning about Parkinson Disease. National Human Genome Research Institute. June 27, 2011; http://www.genome.gov/10001217. Accessed 10/2/2011.
- Parkinson’s disease. MedlinePlus. May 6, 2011; http://www.nlm.nih.gov/medlineplus/ency/article/000755.htm. Accessed 10/3/2011.
- Parkinson disease. Genetics Home Reference (GHR). July 2007; http://ghr.nlm.nih.gov/condition/parkinson-disease. Accessed 10/3/2011.
- Pankratz ND, Wojcieszek J, Foroud T. Parkinson Disease Overview. GeneReviews. July 9, 2009; http://www.ncbi.nlm.nih.gov/books/NBK1223/. Accessed 10/3/2011.