Screening of the mitochondrial A1555G mutation in patients with sensorineural hearing loss.
The A1555G mitochondrial mutation is the main alteration associated with aminoglycoside-induced deafness.


OBJECTIVE
to investigate the prevalence of the A1555G mutation in patients sensorineural hearing loss patients with and without aminoglycosides antibiotic use.


METHODS
a study of 27 cases with deafness as the sample, and 100 neonates with normal hearing as the control group. DNA was extracted from blood leukocyte samples, and specific oligonucleotide primers were designed to amplify the cytochrome b gene and the region which encloses the A1555G mutation of the mitocondrial DNA using the polymerase chain reaction and restriction fragment length polymorphism.


METHODS
a cross-sectional case study.


RESULTS
a region of the cytochrome b gene was amplified and the presence of the mtDNA was confirmed in all of the 127 cases. The A1555G mutation was not found in any of the 27 patients with hearing loss or the control group with 100 neonates.


CONCLUSIONS
the results agree with studies stating that the A1555G mutation is not prevalent in the Americas. There is interest in establishing the real prevalence of this mutation and to investigate other mutations that may cause hearing loss, associated or not with the use of aminoglycosides, in the Brazilian population.
Maniglia
Luciano Pereira
LP
Master's degree student, faculty member of the Otorhinolaryngology and Head & Neck Surgery Department, Medical School, S. J. Rio Preto, SP, FAMERP. Electronic address: vbpiatto@gmail.com.
Moreira
Bruna Carolina Lemos
BCL
Medical student, Medical School, São José do Rio Preto, SP, FAMERP.
da Silva
Magali Aparecida Orate Menezes
MAOM
Master's degree; head of the Speech Therapy Unit, Otorhinolaryngology and Head & Neck Surgery Department, Medical School, S. J. Rio Preto, SP, FAMERP.
Piatto
Vânia Belintani
VB
Doctor, Adjunct professor.
Maniglia
José Victor
JV
Livre-docente (habilitation) professor, head of the Otorhinolaryngology and Head & Neck Surgery Department, Medical School, S. J. Rio Preto, SP, FAMERP. Medical School, São José do Rio Preto, SP, FAMERP.
D000328:Adult; D000617:Aminoglycosides / Q000009:adverse effects*; D002648:Child; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D004272:DNA, Mitochondrial / Q000235:genetics*; D005260:Female; D005820:Genetic Testing / Q000379:methods*; D006319:Hearing Loss, Sensorineural / Q000139:chemically induced / Q000235:genetics*; D006801:Humans; D008297:Male; D009154:Mutation; D016133:Polymerase Chain Reaction; D012150:Polymorphism, Restriction Fragment Length
D000617:Aminoglycosides; D004272:DNA, Mitochondrial