Histopathologic Features of the Inner Ear Associated With Kearns-Sayre Syndrome

Sensorineural hearing loss in patients with chronic progressive external ophthalmoplegia or Kearns–Sayre syndrome

“…Our finding of a slowly progressive course of hearing impairment in all but one of our patients (patient 12 with A3243G PM) is mainly in accordance with previously reported results demonstrating slowly progressive hearing loss in KSS patients with mtDNA deletions in contrast to abrupt, stepwise loss of hearing in patients harbouring A3243G PM often associated with MELAS [1,15]. Sudden deterioration of hearing in MELAS with stepwise progression and transient partial recoveries may indicate acute metabolic dysfunction of the stria vascularis and cochlear hair cells, whereas slowly progressive symptoms in KSS or CPEO may be explained by progressive degeneration of inner ear structures as formerly described [7].…”

“…Recently, histopathological examinations of temporal bones of MELAS patients harbouring the A3243G PM demonstrated severe degeneration of the stria vascularis and spiral ganglion cells which similarly had been described in KSS patients some years ago [7,16]. Both hair cells and stria vascularis are post-mitotic tissues and accumulation of mutant mtDNA is likely, thus making cochlear structures further susceptible to mtDNA disease.…”

Isolated hearing loss associated with T7511C mutation in mitochondrial DNA

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Proposed molecular and cellular mechanism for aminoglycoside ototoxicity

“…One of the most common phenotypes among individuals with these diseases is sensorineural deafness (see, for example, references 7 and 18). Stria vascularis cells degenerate and die in persons with mitochondrial disease (17 (13). Together, these data indicate a statistically significant correlation between the 1555G mutation and aminoglycoside otosensitivity (13).…”