The diagnosis of Parkinson's disease relies on expert opinion. Autopsy studies, however, have demonstrated that even experienced neurologists misdiagnose Parkinson's disease in about a quarter out of a hundred cases. Diagnostic accuracy at disease onset, when neuroprotective treatment is anticipated to be most effective, is even lower. Thus, there is a crucial need for biomarkers that are disease-specific and which precisely identify early disease stages.
Traditional studies of blood from Parkinson's disease patients have analyzed expression levels of one gene or gene product at a time. We plan to take advantage of 'gene chip' technology allowing expression analysis of up to 22,000 genes on a single glass slide, known as microarray. We hypothesize that a comparison of the gene chip analyses of blood samples from Parkinson's disease patients and normal controls or patients with other neurological diseases will identify a set of signature genes with characteristic expression in patients with Parkinson's disease. These key genes will provide a 'molecular fingerprint' of Parkinson's disease in blood.
We will use bioinformatics techniques to transform this 'molecular fingerprint' into a simple and inexpensive diagnostic test. This test will then be performed by applying widely available Real-time-PCR technology. Most importantly, we will attempt to improve diagnostic accuracy at early disease stages. The PD gene expression test will be administered to patients with subtle neurological problems suggestive of early stages of Parkinson's disease in order to determine whether a positive blood test can predict who will progress over the next years to clinical Parkinson's disease.