Bartter syndrome is a rare inherited kidney disease that makes the body lose too much salt. Usually, the cause is a fault in one of seven known genes. None of this was observed in a teenage boy from an inbred family. Instead, his DNA had a change in a different gene, EGFR, which also affected his skin, leading to lifelong inflammation and hair loss. Strikingly, the gene change did not switch off EGFR entirely, but only partially disabled it. That’s what allowed him to survive into his teens, while kids who lose all their EGFR usually die as newborns. In similar unexplained cases, EGFR should be considered. (https://jmg.bmj.com/content/early/2026/06/29/jmg-2025-111461)