POU3F4 is a transcription factor essential for inner ear development and neural differentiation. As a sequence-specific DNA-binding protein, POU3F4 regulates cochlear morphogenesis by controlling otic mesenchyme cell differentiation and modulating expression of downstream genes including Gli1 1. During early neural development, POU3F4 promotes neuronal differentiation of hippocampal neural stem cells and inhibits their proliferation while enhancing synaptic development 1. Mutations in POU3F4 cause X-linked deafness type 3 (DFN3), accounting for approximately 50% of X-linked non-syndromic hearing loss cases 2. The p.E294G mutation demonstrates the mechanism: abnormal nuclear localization impairs POU3F4's transcriptional activity, disrupting cochlear development through modiolus hypoplasia and reduced stria vascularis populations 2. This leads to progressive hearing loss via mitochondrial dysfunction, reduced ATP production, elevated oxidative stress, and enhanced apoptosis in cochlear tissue 2. Clinically, POU3F4 mutations present with conductive hearing loss progressing to sensorineural deafness 3. Regulatory elements controlling POU3F4 expression span 1 Mb upstream of the coding region, regulated by retinoic acid, Fgf, and Hedgehog signaling pathways 4. Early genetic screening and audiological monitoring are critical for managing POU3F4-related deafness 2.