[Prevalence of the A1555G Mutation in the Mitochondrial DNA in Patients with Cochlear or Vestibular Damage Due to Aminoglycoside-induced Ototoxicity]

Objective: To determine the frequency of the A1555G mutation in the mitochondrial genome among Spanish patients with aminoglycoside-induced ototoxicity.

Patients And Methods: We screened 25 unrelated cases, totalling 39 individuals with cochlear or vestibular damage due to aminoglycoside-induced ototoxicity. This group was made up of 18 subjects from 4 unrelated families with a history of aminoglycoside ototoxicity in more than one relative, 8 subjects from 8 families that also had other relatives with hearing loss in absence of aminoglycoside exposure, and 13 sporadic cases. Among the 13 sporadic cases, there were 3 patients with vestibular involvement. Detection of the A1555G mutation was seen by mean of techniques for molecular diagnosis.

Results: The A1555G mutation was identified in all of the individuals from 4 families with aminoglycoside-induced cochlear damage and in 6 of 8 individuals with familial hearing loss. None of the sporadic cases carried the mutation.

Conclusions: A high proportion of patients with cochlear damage due to aminoglycoside ototoxicity and having a familial history of hearing loss, related or not to aminoglycoside exposure, harbor the A1555G mutation.