Pathological myopia (PM) is one of the major causes of irreversible blindness worldwide. However, its exact genetic and pathogenic mechanism remains unclear. This study identifies a novel gene, PSMD3 (proteasome 26S Subunit, Non-ATPase3), with a missense mutation in a PM family. Mutation of PSMD3 decreases the mRNA and protein expression, causing apoptosis of human retinal pigment epithelial cells (RPE), and the axial length of mutant mice increased significantly compared with that of wild-type mice, revealing that PSMD3 mutation may be involved in RPE atrophy and elongation of axial length. RPE dysfunction may be responsible for the degeneration process and influence eye development, further providing new insights into PM. (By Dr. Jing Chen, https://jmg.bmj.com/content/early/2023/03/21/jmg-2022-108978 )