Underrepresented Populations in Parkinson's Genetics Research: Current Landscape and Future Directions

BACKGROUND: Human genetics research lacks diversity; over 80% of genome-wide association studies have been conducted on individuals of European ancestry. In addition to limiting insights regarding disease mechanisms, disproportionate representation can create disparities preventing equitable implementation of personalized medicine. OBJECTIVE: This systematic review provides an overview of research involving Parkinson's disease (PD) genetics in underrepresented populations (URP) and sets a baseline to measure the future impact of current efforts in those populations. METHODS: We searched PubMed and EMBASE until October 2021 using search strings for "PD," "genetics," the main "URP," and and the countries in Latin America, Caribbean, Africa, Asia, and Oceania (excluding Australia and New Zealand). Inclusion criteria were original studies, written in English, reporting genetic results on PD from non-European populations. Two levels of independent reviewers identified and extracted information. RESULTS: We observed imbalances in PD genetic studies among URPs. Asian participants from Greater China were described in the majority of the articles published (57%), but other populations were less well studied; for example, Blacks were represented in just 4.0% of the publications. Also, although idiopathic PD was more studied than monogenic forms of the disease, most studies analyzed a limited number of genetic variants. We identified just nine studies using a genome-wide approach published up to 2021, including URPs. CONCLUSION: This review provides insight into the significant lack of population diversity in PD research highlighting the immediate need for better representation. The Global Parkinson's Genetics Program (GP2) and similar initiatives aim to impact research in URPs, and the early metrics presented here can be used to measure progress in the field of PD genetics in the future. © 2022 International Parkinson and Movement Disorder Society

A Preliminary Investigation of Neuroantibody Levels, Prevalence, and Environmental Factors in Patients with Neurological Dysfunction

Nervous system damage comprises a large proportion of diseases worldwide. It is also the most difficult to diagnose. Biomarkers for nervous system damage are needed in order to diagnose these diseases early enough to allow for intervention. In this study, we recruited patients from two Egyptian hospitals with MCI, ET and NMS and health references. Serum autoantibody levels against neural proteins and heavy metals were analyzed and compared. Immunoglobulin G (IgG) antibodies against neurofilament H (NFH), Glial Fibrillary Acidic Protein (GFAP), Myelin Basic Protein (MBP) and alpha synuclein (a-SYN) and Immunoglobulin M (IgM) antibody against neurofilament light (NFL) were among the most significant promising biomarkers of nervous system damage. Among the heavy metals, Zn and Pb were the most significant showing an association with neurotoxicity and had a positive correlation with the aforementioned autoantibodies. To conclude, this is a case-control study of 94 patients to determine general biomarkers of nervous system damage. This study gives us a new insight about the pathogenesis of these diseases and provides a starting point for more research in this area of biomarkers research in neurodegenerative diseases

Precision health in Alzheimer disease: Risk assessment-based strategies

Alzheimer disease (AD) is a chronic neurodegenerative condition that affects an individual\u27s cognitive function over an extended period. Treatment and prevention for AD have long been sought after; however, no strategy has yet been successful, as individuals with cognitive impairment usually present to the clinic when they have reached an advanced stage of the disease. The disease is progressive and multifactorial in its pathogenesis. Precision medicine (PM) is the new era of medicine comprising a holistic approach in dealing with diseases. With scientific innovations, PM has improved our disease knowledge, altered diagnoses and therapy approaches resulting in a more precise, predictive, preventative and personalized patient care. PM in AD focuses, among other things, on stratifying individuals according to their risk factors of developing the disease and applying preventative strategies and personalized treatment approaches for a better outcome. In this mini-review, we have focused on a few modifiable and non-modifiable risk factors and presented recommendations for future consideration to implement

Mercury and Alzheimer’s disease: a look at the links and evidence

This review paper investigates a specific environmental-disease interaction between mercury exposure and Alzheimer’s disease hallmarks. Alzheimer’s disease is a neurodegenerative disorder affecting predominantly the memory of the affected individual. It prevails mostly in the elderly, rendering many factors as possible causative agents, which potentially contribute to the disease pathogenicity cumulatively. Alzheimer’s disease affects nearly 50 million people worldwide and is considered one the most devastating diseases not only for the patient but also for their families and caregivers. Mercury is a common environmental toxin, found in the atmosphere mostly due to human activity, such as coal-burning for heating and cooking. The natural release of mercury into the atmosphere occurs by volcanic eruptions, in the form of vapor, or weathering rocks. The most toxic form of mercury to humans is methylmercury, to which humans are exposed by the ingestion of fish. Methylmercury was found to exert its toxic effects on different parts of the human body, with predominance on the brain. There is no safe concentration for mercury in the atmosphere, even trace amounts can elicit harm to humans in the long term. Mercury’s effect on Alzheimer\u27s disease hallmarks formation, extracellular senile plaques, and intracellular neurofibrillary tangles, has been widely studied. This review demonstrates the involvement of mercury, in its different forms, in the pathway of amyloid-beta deposition and tau tangles formation. It aims to understand the link between mercury exposure and Alzheimer’s disease so that, in the future, prevention strategies can be applied to halt the progression of this disease

Gut brain axis: an insight into microbiota role in Parkinson\u27s disease

Parkinson\u27s disease (PD) is one of the most common progressive neurodegenerative diseases. It is characterized neuropathologically by the presence of alpha-synuclein containing Lewy Bodies in the substantia nigra of the brain with loss of dopaminergic neurons in the pars compacta of the substantia nigra. The presence of alpha-synuclein aggregates in the substantia nigra and the enteric nervous system (ENS) drew attention to the possibility of a correlation between the gut microbiota and Parkinson\u27s disease. The gut-brain axis is a two-way communication system, which explains how through the vagus nerve, the gut microbiota can affect the central nervous system (CNS), including brain functions related to the ENS, as well as how CNS can alter various gut secretions and immune responses. As a result, this dysbiosis or alteration in gut microbiota can be an early sign of PD with reported changes in short chain fatty acids, bile acids, and lipids. This gave rise to the use of probiotics and faecal microbiota transplantation as alternative approaches to improve the symptoms of patients with PD. The aim of this review is to discuss investigations that have been done to explore the gastrointestinal involvement in Parkinson\u27s disease, the effect of dysbiosis, and potential therapeutic strategies for PD

Mercury and Alzheimer’s disease: a look at the links and evidence

This review paper investigates a specific environmental-disease interaction between mercury exposure and Alzheimer’s disease hallmarks. Alzheimer’s disease is a neurodegenerative disorder affecting predominantly the memory of the affected individual. It prevails mostly in the elderly, rendering many factors as possible causative agents, which potentially contribute to the disease pathogenicity cumulatively. Alzheimer’s disease affects nearly 50 million people worldwide and is considered one the most devastating diseases not only for the patient, but also for their families and caregivers. Mercury is a common environmental toxin, found in the atmosphere mostly due to human activity, such as coal burning for heating and cooking. Natural release of mercury into the atmosphere occurs by volcanic eruptions, in the form of vapor, or weathering rocks. The most toxic form of mercury to humans is methylmercury, to which humans are exposed to by ingestion of fish. Methylmercury was found to exert its toxic effects on different parts of the human body, with predominance on the brain. There is no safe concentration for mercury in the atmosphere, even trace amounts can elicit harm to humans in the long term. Mercury’s effect on Alzheimer’s disease hallmarks formation, extracellular senile plaques and intracellular neurofibrillary tangles, has been widely studied. This review demonstrates the involvement of mercury, in its different forms, in the pathway of amyloid beta deposition and tau tangles formation. It aims to understand the link between mercury exposure and Alzheimer’s disease so that, in the future, prevention strategies can be applied to halt the progression of this disease