Defining and diagnosing neurodegenerative Movement Disorders through integrated analysis of Genetics And neuroPathology (MD-GAP)

We are entering an era in which therapies for degenerative diseases such as Parkinson's and Alzheimer's will be directed towards the underlying protein pathology. Most progressive later onset neurological diseases involve the deposition of abnormal insoluble proteins as aggregates, for example Lewy bodies in Parkinson's and amyloid plaques in Alzheimer's.

There are now an increasing number of experimental therapies which are directed towards protein pathology, for example involving antibodies and gene based therapies. Genetics has provided tremendous insights into neurological disease, largely based on studies in clinically diagnosed patients. Neuropathology is the "gold standard" for the diagnosis of neurological diseases, and the MRC and UK charities have invested in developing the MRC UK Brain Banks Network (BBN) to enable better understanding of these conditions.

Here, we will integrate high throughput genetic analysis with neuropathology to improve the diagnosis and understanding of neurological disease.

Early diagnosis: is a major barrier to the delivery of effective treatment. At the earliest disease stages typical disease features may not be apparent. For example, slowness of movement (Parkinsonism) can be due to multiple different diseases including Parkinson's disease, and a definite diagnosis may not become apparent until the clinical course and response to treatment are established.

We will study genetic variant data from pathologically diagnosed cases to improve early diagnosis. We believe that diagnostic algorithms based on analyzing many genetic markers (polygenic risk) will improve the clinical diagnosis.

Improved case-control analysis: will be achieved by comparing individuals with pathologically proven diseases such as Parkinson's with controls unaffected by neurological disease. This will remove the effect of clinical misdiagnosis in the analysis of neurological disease.

Disease heterogeneity: is an important feature of conditions such as Parkinson's. Some patients develop dementia and rapidly progressive disease whereas others have a more benign, milder disease course. We believe that this heterogeneity is driven by differential neuropathology.

For example, dementia in Parkinson's is associated with Alzheimer's co-pathology (amyloid plaques and neurofibrillary tangles). We will directly study the genetic drivers of co-pathology and integrate this with analyses of clinical heterogeneity to decode the different patterns of neurological disease, which may ultimately respond to different therapies.

Improving resources: The BBN is used by researchers into neurological disease from around the world. There is a growing need to understand the implications of genetic risk factors - and one of the most straightforward ways to do this is to look at brain tissue from individuals with and without the genetic risk factor. This genetic data will be made available to bona fide researchers which will speed up this process and allow researchers to select tissue and samples of interest, maximising the usefulness of these patient tissue archives.