Normal hearing in a child with the m.1555A>G mutation despite repeated exposure to aminoglycosides. Has the penetrance of this pharmacogenetic interaction been overestimated?

Int J Pediatr Otorhinolaryngol. 2014 Jun;78(6):969-73. doi: 10.1016/j.ijporl.2014.02.015. Epub 2014 Feb 21.


The mtDNA m.1555A>G mutation causes increased susceptibility to aminoglycoside ototoxicity resulting in significant hearing loss in 100% of reported exposed cases. Genetic and audiological assessments were conducted in a sample of 59 children with cystic fibrosis (CF) undergoing aminoglycoside treatment. Of the two m.1555G patients identified one had severe-profound deafness. Surprisingly, the second m.1555G patient exhibited well-preserved hearing despite repeated exposure. This may be a rare case of intact hearing in an m.1555G individual with aminoglycoside use. Alternatively, its penetrance may have been previously overestimated due to recruitment bias. Further studies are required to determine the true penetrance to inform m.1555A>G genetic testing in similar clinical scenarios.

Keywords: 12S rRNA gene; A1555G, m.1555A>G; Aminoglycosides; Cystic fibrosis; Hearing loss; Ototoxicity.

Publication types

  • Case Reports
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aminoglycosides / adverse effects*
  • Child
  • Child, Preschool
  • Cystic Fibrosis / drug therapy
  • Cystic Fibrosis / genetics*
  • DNA Mutational Analysis
  • DNA, Mitochondrial / genetics*
  • Female
  • Hearing / drug effects*
  • Hearing / genetics
  • Hearing Loss / chemically induced
  • Hearing Loss / genetics*
  • Hearing Tests
  • Humans
  • Penetrance
  • Pharmacogenetics
  • Point Mutation*
  • RNA, Ribosomal / genetics


  • Aminoglycosides
  • DNA, Mitochondrial
  • RNA, Ribosomal
  • RNA, ribosomal, 12S