Different clinical characteristics of aminoglycoside-induced profound deafness with and without the 1555 A-->G mitochondrial mutation.
Recent genetic studies have shown that hereditary susceptibility to aminoglycoside antibiotics is caused by the 1555 A-->G mitochondrial mutation. We found the 1555 mutation in 4 out of 68 postlingual deaf patients who were candidates for cochlear implantation. All 4 patients developed bilateral profound hearing loss following administration of aminoglycosides. The pedigree of the family shows exclusively maternal transmission of hearing impairment in each case. On comparison with neuro-otological findings from aminoglycoside-induced deaf patients without the 1555 mutation, four distinct characteristics were noted: (1) a progressive nature of hearing loss; (2) better residual pure-tone thresholds; (3) lower thresholds for electrical promontory stimulation, and (4) well-preserved vestibular function. Although other factors such as differing dosages and/or administration routes may also be involved, profound hearing loss associated with the 1555 mutation may be due to a different pathogenic mechanism, i.e., strial dysfunction rather than a direct insult to the hair cells.
Tono
T
T
Department of Otorhinolaryngology, Miyazaki Medical College, Miyazaki, Japan. tono@post1.miyazaki-med.ac.jp
Kiyomizu
K
K
Matsuda
K
K
Komune
S
S
Usami
S
S
Abe
S
S
Shinkawa
H
H
D000368:Aged; D000617:Aminoglycosides; D000900:Anti-Bacterial Agents / Q000009:adverse effects*; D001301:Audiometry, Pure-Tone; D004272:DNA, Mitochondrial / Q000235:genetics*; D003638:Deafness / Q000139:chemically induced* / Q000235:genetics*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009154:Mutation; D010375:Pedigree
D000617:Aminoglycosides; D000900:Anti-Bacterial Agents; D004272:DNA, Mitochondrial