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February 9, 2012

Parkinson's Disease (cont.)

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What genes are linked to Parkinson's disease?

In most individuals, Parkinson's disease is idiopathic, which means that it arises sporadically with no known cause. However, about 15% of individuals have family members with Parkinson's disease. By studying families with hereditary Parkinson's disease, scientists have identified several genes that are associated with the disorder. Studying these genes helps understand the cause of Parkinson's disease and may lead to new therapies. So far, five genes have been identified that are definitively associated with Parkinson's disease.

  1. SNCA (synuclein, alpha non A4 component of amyloid precursor): SNCA makes the protein alpha-synuclein. In brain cells of individuals with Parkinson's disease, this protein aggregates in clumps called Lewy bodies. Mutations in the SNCA gene are found in early-onset Parkinson's disease.

  2. PARK2 (Parkinson's disease autosomal recessive, juvenile 2): The PARK2 gene makes the protein parkin. Mutations of the PARK2 gene are mostly found in individuals with juvenile Parkinson's disease. Parkin normally helps cells break down and recycle proteins.

  3. PARK7 (Parkinson's disease autosomal recessive, early onset 7): PARK7 mutations are found in early-onset Parkinson's disease. The PARK7 gene makes the DJ-1 protein, which may protect cells from oxidative stress.

  4. PINK1 (PTEN-induced putative kinase 1): Mutations of this gene are found in early-onset Parkinson's disease. The exact function of the protein made by PINK1 is not known, but it may protect structures within the cell called mitochondria from stress.

  5. LRRK2 (leucine-rich repeat kinase 2): LRRK2 makes the protein dardarin. Mutations in the LRRK2 gene have been linked to late-onset Parkinson's disease.

Several other chromosome regions and the genes GBA (glucosidase beta acid), SNCAIP (synuclein alpha interacting protein), and UCHL1 (ubiquitin carboxyl-terminal esterase L1) may also be linked to Parkinson's disease.

Who is at risk for Parkinson's disease?

  • Age is the largest risk factor for the development and progression of Parkinson's disease. Most people who develop Parkinson's disease are older than 60 years years of age.

  • Men are affected about 1.5 to 2 times more often than women.

  • A small number of individuals are at increased risk because of a family history of the disorder.

  • Head trauma, illness, or exposure to environmental toxins such as pesticides and herbicides may be a risk factor.

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