CABP2 (calcium binding protein 2) is a calcium-binding regulatory protein essential for auditory function. Its primary role is modulating presynaptic CaV1.3 voltage-gated calcium channel function in inner hair cells (IHCs) of the cochlea 1. Mechanistically, CABP2 inhibits the inactivation of CaV1.3 calcium channels, sustaining their availability for sustained synaptic transmission during sound encoding 2. This function is critical for converting sound vibrations into electrical signals at the IHC synapse; loss of CABP2 results in enhanced calcium channel inactivation and impaired auditory signal transmission 2. CABP2 is preferentially expressed in IHCs rather than postsynaptic neurons, and mice lacking functional CABP2 show intact cochlear amplification but severely reduced spontaneous and sound-evoked neuronal firing rates 2. Biallelic CABP2 variants cause DFNB93, a form of non-syndromic sensorineural hearing loss classified as auditory synaptopathy 1. The hearing loss is typically prelingual and ranges from moderate to severe 3, with phenotypic heterogeneity observed across families 3. Given the established role of IHC synaptic dysfunction in progressive hearing loss and successful gene therapy approaches in related conditions, CABP2 gene replacement represents a promising therapeutic target for hearing restoration 1.