Precision medicine promises more effective treatment for Parkinson's disease, advances in therapeutic development, and fairer care. To fulfill this promise for all patients, it is necessary to study the disease in populations other than those traditionally studied. This approach brings many advantages. An example is the identification of the GBA1 risk factor for Parkinson's disease in West Africa in 2023 thanks to a global collaboration. GBA1 is a common risk factor in more than 40% of Parkinson's patients from Nigeria.