mtDNA mutations, hearing loss and aminoglycoside treatment in Mexicans.
Streptomycin and aminoglycoside derivatives are commonly used to treat tuberculosis and other stubborn infections; these drugs may alter auditory and/or vestibular function. Mutations in mitochondrial DNA have been associated with hypersensitivity to aminoglycosides; no studies have been conducted in Mexicans, which are very prone to such alterations because aminoglycosides have been prescribed carelessly for many years, irrespective of the ailment to be treated.


OBJECTIVE
We investigated "hot spot" mutations described previously as causing inner ear alterations.


METHODS
Hot spot mutations at the 12S rRNA gene and the tRNA Serine (UCN) gene were screened by PCR-RFLP and sequencing in 65 subjects undergoing audiological and vestibular testing.


METHODS
Experimental.


RESULTS
32 individuals had healthy auditory and vestibular function, whereas 33 subjects had auditory affections. We found none of the previously reported mutations related to aminoglycoside hypersensitivity, or non-syndromic hearing loss. Two hearing-impaired patients that had been treated with streptomycin had the T1189C variant of the mitochondrial 12S rRNA region.


CONCLUSIONS
Mutations related to hearing loss in other ethnic backgrounds were not found in Mexicans. However, the T1189C variant is possibly a putative mutation related to aminoglycoside hypersensitivity and was present in 2 patients.
División de Neurociencias, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México. gmeza@ifc.unam.mx
G
G
Meza
N M
NM
Torres-Ruíz
C
C
Tirado-Gutiérrez
P
P
Aguilera
D000293:Adolescent; D000328:Adult; D000368:Aged; D000617:Aminoglycosides / Q000009:adverse effects*; D002648:Child; D002675:Child, Preschool; D004252:DNA Mutational Analysis; D004272:DNA, Mitochondrial / Q000187:drug effects* / Q000235:genetics; D020022:Genetic Predisposition to Disease; D034381:Hearing Loss / Q000139:chemically induced* / Q000235:genetics; D006801:Humans; D008800:Mexico; D008875:Middle Aged; D017354:Point Mutation / Q000187:drug effects* / Q000235:genetics; D016133:Polymerase Chain Reaction; D012150:Polymorphism, Restriction Fragment Length; D012335:RNA, Ribosomal / Q000187:drug effects* / Q000235:genetics; D012362:RNA, Transfer, Ser / Q000187:drug effects* / Q000235:genetics; D013307:Streptomycin / Q000009:adverse effects; D055815:Young Adult
D000617:Aminoglycosides; D004272:DNA, Mitochondrial; D012335:RNA, Ribosomal; D012362:RNA, Transfer, Ser; C075526:RNA, ribosomal, 12S; D013307:Streptomycin