GJD4 (gap junction protein delta 4) encodes a connexin that assembles into hexameric hemichannels (connexons) forming gap junction channels, which facilitate intercellular communication by allowing passage of low molecular weight materials between adjacent cells 1. GJD4 functions as a gap junction channel protein with charge and size-dependent selectivity for solutes 2, enabling regulated cell-to-cell signaling through protein binding and connexin complex formation. GJD4 has been identified as a candidate gene in multiple physiological contexts. In poultry genetics, the GJD4-CCNY chr10 region showed selection signatures associated with abdominal fat content variation, suggesting roles in metabolic regulation 3. In auditory function, GJD4 was identified within a quantitative trait locus (Maced) mapping endocochlear potential variation and marginal cell density in the cochlear stria vascularis, implicating it in hearing regulation 4. Additionally, GJD4 was sequenced as a candidate gene in a novel Usher syndrome type 1 locus (USH1K) on chromosome 10.21-q21.1, though no pathogenic mutations were identified in affected families 5. The clinical significance of GJD4 relates to sensory and metabolic disorders. Gap junction dysfunction, as mediated by connexins including GJD4, may contribute to hearing loss and age-related presbycusis through effects on cochlear ion homeostasis. GJD4 represents a potential therapeutic target for disorders involving intercellular communication defects.