MiGAP

Changes in the genetic information (mutations) in the glucocerebrosidase beta (GBA) gene cause Gaucher's disease, a common lysosomal metabolic disease. The genetic defect leads to a reduced activity of the protein (enzyme) glucocerebrosidase, which is located in the lysosomes, so that sugary fatty substances (glucosylceramides) are insufficiently degraded and accumulate. Family studies in Gaucher patients showed that family members were more likely to develop Parkinson's syndrome. Today, heterozygous GBA mutations, which are present in up to 10% of Parkinson's disease patients, represent the most important genetic risk factor for Parkinson's disease to date, with a 2 to 10-fold increase in risk of Parkinson's disease. Parkinson's disease patients with GBA mutations often suffer from non-motor symptoms such as dementia, depression and cardiovascular abnormalities (autonomic dysfunctions) and show rapid progression. Analyses of the brain show extensive deposits of alpha-synucleic protein (aSYN pathology), which may explain the progression and partly early cognitive limitations.

With regard to pathophysiology, a mutually reinforcing mechanism with reduced glucocerebrosidase enzyme activity and glucosylceramide accumulation with lysosomal dysfunction and aSYN aggregation is currently being assumed. The identification of these mechanisms opens up new cause-related therapy concepts.

The aim of the MiGAP study is a geno-phenotypic characterization of GBA-associated Parkinson's disease with regard to motor and non-motor symptoms and the identification of specific biomarkers in blood, cerebrospinal fluid and cell models. Furthermore, this cohort is a ready-for-trial-cohort for future cause-specific studies.

In the MiGAP study, a total of 400 participants with and without Parkinson's disease are being studied, with both groups of people with and without GBA mutation. The inclusion age is between 40 and 90 years.

Longitudinal study design with annual visits.

Investigations within the scope of the study include a clinical neurological examination by a study physician, a neuropsychological examination, the assessment of autonomous functions (such as heart rate), a gait analysis and a measurement of olfactory function. A blood sample is also taken. With the appropriate consent, a lumbar puncture (nerve water collection) and/or a skin biopsy is also performed.

Principle Investigator: Prof. Dr. Thomas Gasser, Dr. Kathrin Brockmann
Start of the study: 2015
Status: multi centric, ongoing, recruiting completed