The mitochondrial A3243G mutation involves the peripheral vestibule as well as the cochlea

Laryngoscope. 2011 Aug;121(8):1821-4. doi: 10.1002/lary.21879.


Objectives/hypothesis: To evaluate vestibular function in patients with the mitochondrial A3243G mutation.

Study design: Data from patients with the A3243G mutation attending an academic tertiary referral center were prospectively recorded.

Methods: The clinical histories of 13 unrelated patients with the mitochondrial A3243G mutation (six mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes; and seven maternally inherited diabetes and deafness) were recorded, in particular their history of vestibular symptoms. Vestibular examinations including caloric testing and vestibular evoked myogenic potentials in response to air-conducted sound (ACS-VEMPs) were performed. In seven patients who showed abnormal ACS-VEMP, VEMP in response to galvanic stimuli (galvanic-VEMP) were also recorded.

Results: Eleven of the 13 patients had vestibular symptoms. The age of onset of vestibular symptoms was significantly later than the ages of onset of hearing loss and diabetes mellitus (P < .05). Ten of the 13 patients showed abnormal caloric responses, whereas 12 patients showed abnormal ACS-VEMPs on one or both sides. All of the seven patients who underwent galvanic-VEMP testing showed normal responses.

Conclusions: The A3243G mutation is associated with vestibular dysfunction involving both the superior and inferior vestibular nerve systems. Furthermore, our results from galvanic-VEMP testing suggests that a labyrinthine lesion is primarily responsible for the symptoms of vestibular dysfunction.

MeSH terms

  • Acoustic Stimulation
  • Adult
  • Auditory Threshold
  • Body Surface Potential Mapping
  • Caloric Tests
  • Cochlea / physiopathology*
  • DNA, Mitochondrial / genetics*
  • Diabetes Complications
  • Electromyography
  • Female
  • Hearing Loss, Sensorineural / genetics
  • Hearing Loss, Sensorineural / physiopathology
  • Humans
  • MELAS Syndrome / genetics
  • MELAS Syndrome / physiopathology
  • Male
  • Middle Aged
  • Mitochondrial Diseases / genetics*
  • Mitochondrial Diseases / physiopathology
  • Point Mutation*
  • Vestibular Diseases / genetics*
  • Vestibular Diseases / physiopathology*
  • Vestibular Evoked Myogenic Potentials*
  • Vestibular Function Tests


  • DNA, Mitochondrial