Contribution of Genetics to Parkinson's Disease and Future Prospects.

Parkinson's disease (PD) is a systemic neurodegenerative disorder that is characterized by motor and non-motor symptoms. Although aging is the primary risk factor, environmental and genetic factors also contribute to risk, and identifying genetic risks may aid in preventive strategies. The present perspective outlines the two main genetic research strategies: research into familial PD using known causative gene screening and next-generation sequencing, and the analysis of sporadic PD using genome-wide association studies (GWAS). Recent advances in next-generation sequencing have improved gene screening, allowing researchers to quickly and inexpensively identify novel rare variants. However, challenges remain, such as accurately analyzing repetitive sequences and structural variants. The role of neurologists in gathering clinical and genomic data ─ especially from familial cases ─ is crucial. International collaborations, such as the Global Parkinson's Genetic Program, address issues such as population diversity and missing heritability in GWAS. Contributions from Juntendo University include the discovery of PD-related genes and the implementation of validation studies in Japanese populations. We also aim to develop molecular targeted therapies using induced pluripotent stem cells. To elucidate the unknown causes of PD and advance treatment approaches, it is important to continuously conduct genetic research.