SLC17A8 encodes vesicular glutamate transporter 3 (VGLUT3), a multifunctional transporter primarily functioning as a uniporter that mediates L-glutamate uptake into synaptic vesicles at presynaptic nerve terminals 1. The protein is uniquely expressed in inner hair cells of the cochlea among the VGLUT isoforms, where it transports glutamate into synaptic vesicles for neurotransmitter release 2. VGLUT3 operates through an electrogenic mechanism driven by the proton electrochemical gradient established by vacuolar H+-ATPase across synaptic vesicle membranes 1. Beyond the inner ear, SLC17A8 shows tissue-specific expression patterns, including hepatocytes where VGLUT3 accumulates glutamate in vesicles and can trigger inflammatory responses in Kupffer cells 3. Mutations in SLC17A8 cause DFNA25, an autosomal dominant form of hearing loss, with pathogenic variants including frameshift mutations like p.M206Nfs*4 that produce truncated proteins lacking essential transmembrane domains 24. Gene therapy targeting SLC17A8 has shown therapeutic potential, with successful hearing restoration in adult deaf mice through cerebrospinal fluid delivery of functional SLC17A8 5. The gene's role extends to neuropsychiatric conditions, with variants identified in Tourette syndrome families 6.