Class Year



Hearing disorders, Hearing loss, PMCA2, auditory system function


Deafness, a pathological condition causing partial or complete loss of hearing, affects nearly 70 million people worldwide. Research has linked nonsyndromic deafness to over 30 genes. In this review, implications of mutations on four of these genes will be discussed to understand how normal function is altered. While various mutations are linked to deafness, little is known about the mechanisms that lead to deafness. MyosinVI mutations hinder the motor protein’s progressive movement, rendering the protein unable to stabilize stereocilia. Point mutations in PMCA2 gene in outer hair cells (OHCs) cause a defect in the calcium pump, leading to a change in calcium concentration in the cell and loss of hearing and imbalance. Mutations on the KCNQ4 gene in the OHCs cause K+ channel malfunction, ceasing the removal of K+ and inhibiting repolarization, thus leading to degeneration of the cell. Connexin 26 mutations lead to destruction and degradation of critical components within the inner ear, as well as problems with gap junction communication. These mutations cause autosomal recessive deafness. Currently, there is no cure for deafness, but development of treatments such as cochlear implants and other electrical systems can improve the quality of hearing. Identification and a deeper understanding of new genetic mutations can enhance treatments.


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