Mitochondrial 12S rRNA susceptibility mutations in aminoglycoside-associated and idiopathic bilateral vestibulopathy

The mitochondrial 12S rRNA is considered a hotspot for mutations associated with nonsyndromic (NSHL) and aminoglycoside-induced hearing loss (AIHL). Although aminoglycoside ototoxicity is the most common cause of bilateral vestibular dysfunction, the conceivable role of 12S rRNA mutations has never been systematically investigated. We sequenced the 12S rRNA of 66 patients with bilateral vestibulopathy (BV) with (n = 15) or without (n = 51) prior exposure to aminoglycosides, as well as 155 healthy controls with intact vestibular function (sport pilots), and compared these to 2704 published sequences (Human Mitochondrial Genome Database). No mutations with a confirmed pathogenicity were found (A1555G, C1494T), but four mutations with a hitherto tentative status were detected (T669C, C960del, C960ins, T961G). Due to their predominant occurrence in patients without aminoglycoside exposure, their detection in controls and a weak evolutionary conservation, their pathogenic role in vestibulocochlear dysfunction remains provisional.