Long-Term Progression of Hearing Loss associated with the mitochondrial gene 3243A>G variant and GJB2 gene variant

Abstract

　 Although the hearing prognosis in patients with hereditary hearing loss is still largely unclear, an increasing number of studies have followed the long-term course of hearing loss. In this paper, we describe the long-term hearing outcomes of cases of hearing loss associated with the mitochondrial 3243A>G variant and those associated with GJB2 mutation. Patients with hearing loss associated with mitochondrial 3243A>G have, in general, normal hearing at birth, but hearing loss develops later in life, appearing as early as in the teenage years/20s or as late as in the 50s. In general, the hearing loss is bilateral and symmetrical, and most cases show bilateral progression with horizontal or high-pitched, rapid-collision sensorineural hearing loss. The hearing threshold decreases gradually, but some cases are scattered with acute profound sensorineural hearing loss. Hearing loss due to GJB2 mutation varies from mild to severe and is considered to be non-progressive. However, recent studies suggest that these patients may also develop progressive hearing loss. Regular hearing monitoring is important for both types of inherited hearing loss, as these condition often progresses to severe hearing loss.