Phenotype of DFNA11: a nonsyndromic hearing loss caused by a myosin VIIA mutation.
OBJECTIVE
To characterize the audiovestibular phenotype of DFNA11, an autosomal dominant nonsyndromic hearing impairment caused by a mutation in the myosin VIIA gene (MYO7A), including whether DFNA11-affected subjects have retinal degeneration as is characteristic of Usher syndrome type 1B, caused by different MYO7A mutations.


METHODS
Retrospective study of audiovestibular and ophthalmological data in a Japanese family linked to DFNA11.


METHODS
Otoscopic examination and pure-tone audiometry were performed in all participants in the family. Selected subjects underwent additional examinations including speech discrimination scoring, acoustic reflex measurements, Békésy audiometry, evoked and distortion-product otoacoustic emissions, auditory brainstem responses, and bithermal caloric testing; visual acuity, ocular tonometry, slit-lamp examination, ophthalmoscopy, and electroretinography; and computed tomography of the temporal bone.


RESULTS
Most affected individuals had moderate cochlear hearing loss beginning in the second decade and progressing at all frequencies. Variable degrees of asymptomatic vestibular dysfunction were present. Computed tomography showed normal inner and middle ear structures. No evidence suggested retinitis pigmentosa.


CONCLUSIONS
The phenotype of DFNA11 is postlingual, nonsyndromic sensorineural hearing loss with gradual progression. Showing moderate hearing loss with asymptomatic variable vestibular dysfunction and no retinal degeneration, the DFNA11 phenotype is mildest among phenotypes caused by MYO7A mutations.
Tamagawa
Yuya
Y
Department of Otolaryngology, Jichi Medical School, Minamikawachi, Japan. tama@jichi.ac.jp
Ishikawa
Kazuhiro
K
Ishikawa
Kotaro
K
Ishida
Takashi
T
Kitamura
Ken
K
Makino
Shinji
S
Tsuru
Tadahiko
T
Ichimura
Keiichi
K
D048868:Adaptor Proteins, Signal Transducing; D000328:Adult; D000368:Aged; D001299:Audiometry; D002352:Carrier Proteins / Q000235:genetics*; D018450:Disease Progression; D004398:Dyneins; D005260:Female; D005500:Follow-Up Studies; D000080865:Formins; D006319:Hearing Loss, Sensorineural / Q000175:diagnosis* / Q000453:epidemiology / Q000235:genetics*; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009154:Mutation / Q000235:genetics*; D000081412:Myosin VIIa; D009218:Myosins / Q000235:genetics*; D010641:Phenotype; D012189:Retrospective Studies; D012307:Risk Factors; D012720:Severity of Illness Index; D014724:Vestibular Function Tests
D048868:Adaptor Proteins, Signal Transducing; D002352:Carrier Proteins; C108962:DIAPH1 protein, human; D000080865:Formins; C000631455:MYO7A protein, human; D000081412:Myosin VIIa; D009218:Myosins; D004398:Dyneins