Rare diseases are, by definition, infrequent, which makes recognizing consistent disease patterns nearly impossible without aggregating cases from across the globe. Global registries allow researchers to detect commonalities in symptoms, progression, and otherwise invisible outcomes in small, siloed datasets. For instance, IndoUSrare supported a family in India whose child exhibited neurological symptoms that initially baffled local doctors. Physicians discovered a matching cluster of European cases by plugging their data into a global registry, rapidly diagnosing an ultra-rare leukodystrophy and timely intervention. Shared data enabled pattern recognition where national systems had failed.