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In the present study we assessed the prevalence and nature of hearing loss in patients with chronic progressive external ophthalmoplegia (CPEO) or Kearns-Say re syndrome (KSS) due to single large-scale mitochondrial DNA(mtDNA) deletion o r mtDNA tRNA Leu(UUR) A3243G point mutation (A3243G PM). 14 patients with mtDNA deletion and three patients with A3243G PM underwent audiological evaluation com prising pure-tone and speech audiometry as well as transient evoked otoacoustic emissions (OAE). Audiological evaluation revealed hearing impairment in 10/17 p atients. Hearing loss was mild to moderate predominantly affecting high frequenc ies in five patients with subjective hearing problems (three patients with mtDNA deletions, two patients with A3243G PM). Subclinical hearing deficits restricte d to high frequencies were seen in further five asymptomatic patients (four pati ents with mtDNA deletions, one patients with A3243G PM). Audiological findings s uggested a cochlear origin of hearing loss in all subjects. Our results demonstr ate that CPEO or KSS patients due to mtDNA deletion or A3243G PM are at high ris k of developing sensorineural hearing deficits.
In the present study we assessed the prevalence and nature of hearing loss in patients with chronic progressive external ophthalmoplegia (CPEO) or Kearns-Say re syndrome (KSS) due to single large-scale mitochondrial DNA (mtDNA) deletion or mtDNA tRNA Leu ) A3243G point mutation (A3243G PM). 14 patients with mDNA deletion and three patients with A3243G PM underwent audiological evaluation com prizing pure-tone and speech audiometry as well as transient evoked otoacoustic emissions (OAE). Audiological evaluation revealed hearing impairment in 10 / 17 p atients. Hearing loss was mild to moderate predominantly affecting high frequenc ies in five patients with subjective hearing problems (three patients with mtDNA deletions, two patients with A3243G PM). Subclinical hearing deficits restricting d to high frequencies were seen in further five asymptomatic patients (four pati ents with mDNA deletions, one patients with A3243G PM). Audiological findings s ugested a cochlear origin of hearing loss in all subjects. Our results demonstr ate that CPEO or KSS patients due to mtDNA deletion or A3243G PM are at high ris k of developing sensorineural hearing deficits.