POF1B is an X-linked actin-binding protein that plays a critical role in organizing epithelial monolayers through regulation of the actin cytoskeleton 1. The protein localizes to multiple cell-cell adhesion structures including tight junctions, adherens junctions, and desmosomes 12. In desmosomal complexes, POF1B associates with desmoplakin and intermediate filaments, where it regulates desmosome assembly and cell mechanical resistance 2. POF1B is specifically expressed in differentiated epithelial tissues, including the granular layer of epidermis and the gastro-intestinal tract, where expression is activated during barrier formation 3. Clinically, POF1B mutations are associated with premature ovarian insufficiency (POI), a condition characterized by ovarian follicle exhaustion before age 40 45. The R329Q variant impairs tight junction assembly and actin organization, causing defective epithelial polarity, ciliogenesis, and cystogenesis 1. However, mutation screening studies show variable POF1B involvement in POI etiology; while mutations have been identified in some patients, large-scale studies suggest POF1B is rarely implicated compared to other POI-associated genes 467. Recent evidence indicates copy number variations in POF1B may contribute to diminished ovarian reserve, though additional functional studies are needed to clarify its role 8.