Aminoglycoside ototoxicity in Nicaraguan children: patient risk factors and mitochondrial DNA results.

OBJECTIVE: Aminoglycoside ototoxicity remains a major problem in developing countries and accounts for 3 percent to 30 percent of hearing loss. This high prevalence rate may be related to genetic susceptibility from mitochondrial mutations in the 12S rRNA gene, comorbidity factors, or unregulated use of the medication. This study investigates the risk factors and prevalence of mtDNA mutations in serum from rural Nicaragua children with aminoglycoside-related hearing loss.

STUDY DESIGN: Cross sectional study.

SUBJECTS: Deaf children from rural Nicaragua.

METHODS: Mitochondrial DNA isolated from serum collected from 31 deaf children with childhood or in utero exposure to gentamicin was amplified, sequenced, and analyzed for mutations in the 12S rRNA gene.

RESULTS: No known pathologic mutations of the 12S rRNA gene were identified in this subpopulation of deaf children. In addition, patients with gentamicin exposure were often likely to have other comorbidity factors.

CONCLUSION: These results suggest that genetic susceptibility is not a major factor in the high rate of gentamicin ototoxicity in this population sample. The high prevalence of gentamicin ototoxicty in this population is presumed to be due to unrestricted access to the drug.