Hearing loss is often caused by genetic variants, but for many people, the underlying cause remains unknown, preventing an accurate diagnosis and limiting access to emerging genetic therapies. We performed whole-exome sequencing in more than 1,000 people with hearing loss and integrated the findings with data from their electronic medical records. Despite incomplete clinical information, our approach identified likely genetic causes in many participants and revealed new candidate genes that may contribute to hearing loss. This work demonstrates how large healthcare databases can improve diagnosis, expand our understanding of the genetic basis of hearing loss, and help prepare more patients for future gene-based therapies. (https://jmg.bmj.com/content/early/2026/09/02/jmg-2026-111784)