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PLoS One. 2012;7(10):e44054. doi: 10.1371/journal.pone.0044054. Epub 2012 Oct 25.

Postlingual hearing loss as a mitochondrial 3243A>G mutation phenotype.

Author information

1
Institute of Physiology and Pathology of Hearing, Warsaw, Poland.

Abstract

BACKGROUND:

The prevalence of isolated hearing loss (HL) associated with the m.3243A>G mutation is unknown. The aim of this study was to assess the frequency and heteroplasmy level of the m.3243A>G mutation in a large group of Polish patients with postlingual bilateral sensorineural HL of unidentified cause.

METHODOLOGY/PRINCIPAL FINDINGS:

A molecular search was undertaken in the archival blood DNA of 1482 unrelated patients with isolated HL that had begun at ages between 5 and 40 years. Maternal relatives of the probands were subsequently investigated and all carriers underwent audiological tests. The m.3243A>G mutation was found in 16 of 1482 probands (an incidence of 1.08%) and 18 family members. Of these 34 individuals, hearing impairment was detected in 29 patients and the mean onset of HL was at 26 years. Some 42% of the identified m.3243A>G carriers did not develop multisystem symptomatology over the following 10 years. Mean heteroplasmy level of m.3243A>G was lowest in blood at a level of 14% and highest in urine at 58%. These values were independent of the manifested clinical severity of the disease.

CONCLUSIONS:

A single m.3243A>G carrier can usually be found among each 100 individuals who have postlingual hearing loss of unknown cause. Urine samples are best for detecting the m.3243A>G mutation and diagnosing mitochondrially inherited hearing loss.

PMID:
23133508
PMCID:
PMC3485002
DOI:
10.1371/journal.pone.0044054
[Indexed for MEDLINE]
Free PMC Article

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