We read with enthusiasm the Comment1 by Andrew Singleton and colleagues about the role of international collaboration in advancing understanding of Parkinson's disease biology. The identification of GBA1 as a major risk factor for Parkinson's disease in west African populations is a clear example of global collaborative efforts.2 Enabled by initiatives such as the Global Parkinson's Genetics Program, the work did more than verify known mechanisms; it showed how much relevant biology remains unrecognised when large regions of the world are excluded from research efforts.