Biomarker Found for Parkinson’s Disease

A mechanism has been identified that appears to underlie the common sporadic nonfamilial form of Parkinson's disease, the progressive movement disorder.

The analysis of human brain tissue, led to the discovery of a protein biomarker that highlights potential new therapeutic targets for Parkinson's and could lead to a blood test for the disease.

Scientists at Taub Institute at Columbia University Medical Center (New York, NY, USA) studied the rare familial and heritable forms of Parkinson's and showed 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. Another key feature of Parkinson's is the presence of excess alpha-synuclein aggregates in the brain.

A variety of techniques was used, including gene-expression analysis and gene-network mapping, and the scientists discovered how common forms of alpha-synuclein contribute to sporadic Parkinson's. They showed that specific ribonucleic acid (RNA) transcript isoforms of alpha-synuclein with an extended 3′ untranslated region, termed aSynL, appear selectively linked to pathological processes, relative to shorter alpha-synuclein transcripts.

The investigators also found elevated levels of the alpha-synuclein elongated transcripts in the blood of a group of patients with sporadic Parkinson's, compared with unaffected controls. This would suggest that a test for alpha-synuclein may serve as a biomarker for the disease. The findings suggest that drugs that reduce the accumulation of elongated alpha-synuclein transcripts in the brain might have therapeutic value in the treatment of Parkinson's.

Asa Abeliovich, MD, PhD, the senior author of the study, said, “Some very common genetic variants in the alpha-synuclein gene, present in many people, are known to impact the likelihood that an individual will suffer from sporadic Parkinson's. In our study, we show that people with 'bad' variants of the gene make more of the elongated alpha-synuclein transcript forms. This ultimately means that more of the disease protein is made and may accumulate in the brain.” The study was published on September 25, 2012, in the journal Nature Communications.

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