Hearing impairment: a panoply of genes and functions.

Research in the genetics of hearing and deafness has evolved rapidly over the past years, providing the molecular foundation for different aspects of the mechanism of hearing. Considered to be the most common sensory disorder, hearing impairment is genetically heterogeneous. The multitude of genes affected encode proteins associated with many different functions, encompassing overarching areas of research. These include, but are not limited to, developmental biology, cell biology, physiology, and neurobiology. In this review, we discuss the broad categories of genes involved in hearing and deafness. Particular attention is paid to a subgroup of genes associated with inner ear gene regulation, fluid homeostasis, junctional complex and tight junctions, synaptic transmission, and auditory pathways. Overall, studies in genetics have provided research scientists and clinicians with insight regarding practical implications for the hearing impaired, while heralding hope for future development of therapeutics.