Clinical symptoms, underlying pathogenesis, and the prospect of tailored therapies have all benefited from genetic discoveries in Parkinson's disease.Even as our understanding of disease biology improves, there are still knowledge gaps that must be filled in the future. Reliable biomarkers that uniquely recapitulate pathophysiological aspects are necessary for patient classification and medication response tracking. Genetic testing is essential in 'idiopathic' or 'sporadic' PD patients to identify those who would benefit from genotype-driven treatment. Genotype-dependent segmentation of research participants will broaden the possible usefulness of targeted treatments. Biomarker-assisted clinical trials will benefit tremendously from new adaptable designs. Recent breakthroughs in genotype-driven therapy, on the other hand, should deliver considerable benefits for Parkinson's patients in the medium term and lead to the development of the first disease-modifying drugs.