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Mechanism That Leads to Non-Familial Parkinson’s Disease Identified
Researchers in the Taub Institute at Columbia University Medical Center (CUMC) have identified a mechanism that appears to underlie the common sporadic (non-familial) form of Parkinson's disease, the progressive movement disorder. The discovery highlights potential new therapeutic targets for Parkinson's and could lead to a blood test for the disease. The study, based mainly on analysis of human brain tissue, was published online on September 25, 2012 in Nature Communications. Studies of rare, familial (heritable) forms of Parkinson's show that a protein called alpha-synuclein plays a role in the development of the disease. People who have extra copies of the alpha-synuclein gene produce excess alpha-synuclein protein, which can damage neurons. The effect is most pronounced in dopamine neurons, a population of brain cells in the substantia nigra that plays a key role in controlling normal movement and is lost in Parkinson's. Another key feature of Parkinson's is the presence of excess alpha-synuclein aggregates in the brain. As the vast majority of patients with Parkinson's do not carry rare familial mutations, a key question has been why these individuals with common sporadic Parkinson's nonetheless acquire excess alpha-synuclein protein and lose critical dopamine neurons, leading to the disease. Using a variety of techniques, including gene-expression analysis and gene-network mapping, the CUMC researchers discovered how common forms of alpha-synuclein contribute to sporadic Parkinson's. "It turns out multiple different alpha-synuclein transcript forms are generated during the initial step in making the disease protein; our study implicates the longer transcript forms as the major culprits," said study leader Asa Abeliovich, M.D., Ph.D., associate professor of pathology and neurology at CUMC.