South Africans – who may have early symptoms of Parkinson’s disease (PD) in the family – are being recruited for a global genetics programme to further deepen the understanding and study of the condition.
The largest known risk factor for PD is increased age, while other risk factors include exposure to environmental factors (like pesticides), male sex, a positive family history and genetic factors.
Over the past 30 years, writes a group of scientists in the South African Medical Journal, the discoveries of pathogenic variants in a large number of genes have highlighted a genetic component in about one in five people with PD.
These discoveries, write Abigail Braun, Riaan van Coller, Ferzana Hassan Amod, Shahida Moosa and Soraya Bardien, have led to important insights into the cellular mechanisms that lead to the death of dopaminergic neurons.
Screen families
The Global Parkinson’s Genetics Programme (GP2, Global Parkinson’s Genetic Programme) is a collaborative effort that has recently been established to improve the understanding on the genetic architecture of PD globally. The emphasis is on families from under-represented populations
GP2 is interested in recruiting large families with PD (≥3 affected relatives) and families with early-onset disease (i.e, age at onset (AAO) of <50 years), and in obtaining DNA samples from both parents of an affected individual, as well as of other affected family members.
Acknowledging the rarity of large PD families and the significant efforts to recruit and obtain blood samples from relatives for genetic studies, incentives will be provided (Family incentive).
Requirements to participate include a GP2-approved consenting process, a blood sample from each participant and relevant clinical information.
South African medical professionals with suitable families, in collaboration with the researchers at Stellenbosch University, will be able to send DNA and relevant patient information to GP2.
Benefits to study participants include:
• genetically-confirmed PD diagnosis and improved clinical management
• patient-centred treatment based on the specific pathogenic variant[
• if a monogenic cause is identified, pre-symptomatic testing of family members who could benefit from disease-modifying treatment, when available
• once a causal variant is identified, the proband can possibly enlist in clinical trials targeted at their specific disease-causing gene e.g. inase inhibitors of LRRK2, should they become available
• ultimately, these genetic findings may aid in the development of novel and more effective drug treatments for PD.
Notably, individuals of African ancestry are distinguished by the greatest levels of genetic diversity worldwide, owing to them being some of the oldest populations, and adaptation of their genomes to changing climates, varying diets and exposure to transmissible diseases over thousands of years. This genetic diversity may lead to novel genetic discoveries for PD.
The collaboration with the GP2 consortium aims to raise awareness that PD has a genetic component.
Through GP2, SA families with PD can be genetically screened at no cost to the study participants or researchers, and the knowledge gained may be of great benefit to people with PD throughout the world.
Abigail Braun, Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, Stellenbosch University; Riaan van Coller, Department of Neurology, University of Pretoria, and Pretoria Institute of Neurology; Ferzana Hassan Amod, Department of Neurology, Inkosi Albert Luthuli Central Hospital, Durban; and Department of Neurology, Faculty of Medicine and Health Sciences, University of KwaZulu-Natal; Shahida Moosa, Division of Molecular Biology and Human Genetics, Stellenbosch University, and Medical Genetics, Tygerberg Hospital; Soraya Bardien, Division of Molecular Biology and Human Genetics, Department of Biomedical Sciences, Stellenbosch University, SA Medical Research Council/Stellenbosch University Genomics of Brain Disorders Research Unit.
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