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Nonsyndromic Hearing Loss Caused by a Mitochondrial T7511C Mutation
Author(s) -
Ishikawa Kotaro,
Tamagawa Yuya,
Takahashi Katsumasa,
Kimura Hiroshi,
Kusakari Jun,
Hara Akira,
Ichimura Keiichi
Publication year - 2002
Publication title -
the laryngoscope
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.181
H-Index - 148
eISSN - 1531-4995
pISSN - 0023-852X
DOI - 10.1097/00005537-200208000-00030
Subject(s) - audiogram , heteroplasmy , audiology , hearing loss , audiometry , medicine , tympanometry , sensorineural hearing loss , mutation , auditory neuropathy , acoustic reflex , genetics , biology , gene
Objectives The aims of the present study were to identify a mutation in a Japanese family showing nonsyndromic sensorineural hearing loss and to relate the mutation to characteristics of patients, including audiovestibular findings. Study Design Familial cohort study. Methods Mutation analysis was performed using genomic DNA extracted from blood samples. Subjects underwent audiovestibular examinations, including pure‐tone audiograms, tympanometry, self‐recording audiometry, acoustic reflex threshold, speech discrimination testing, evoked and distortion‐product otoacoustic emissions, auditory brainstem responses, and caloric testing. Results We identified a T7511C mutation in the mitochondrial tRNA Ser(UCN) gene previously reported in one other family. The degree of heteroplasmy for the T7511C mutation ranged from 84% to 92%, and did not correlate with age at examination or severity of hearing loss. Extensive audiologic evaluation suggested both cochlear and retrocochlear involvement. Conclusion Families with maternally transmitted nonsyndromic hearing loss should be investigated for mutations in the tRNA Ser(UCN) gene.