These proteins are in vivo expressed in a spatiotemporal manner in the inner ear epithelia, including the human medial cochlear duct floor47 and sensory vestibular epithelia.72 Moreover, ATP1A1, implicated in age-related hearing loss,73 has a spatiotemporal expression during the development of the inner ear,46,66 and shows epithelial expression within IEOs (Figure 6F). The gene discussed is ATP1A1; the disease is presbycusis.