Temporal bone histopathologic abnormalities associated with mitochondrial mutation T7511C.

Objectives: We previously reported a mitochondrial T7511C mutation in the tRNA gene in a Japanese family with nonsyndromic hearing loss (HL). However, the temporal bone histopathology associated with T7511C has not been reported. The aim of the present study is to report histopathologic findings of a temporal bone from a patient in the Japanese family with this mutation.

Maternally inherited nonsyndromic hearing loss is associated with the T7511C mutation in the mitochondrial tRNASerUCN gene in a Japanese family.

We report here the characterization of a Japanese family with maternally transmitted nonsyndromic hearing loss. Fourteen of 21 matrilineal relatives in this family exhibited early or late-onset/progressive but noncongenital hearing impairment with a wide range of severity, ranging from severe to normal hearing. The age-of-onset varies from 3 to 30 years.

Temporal bone histopathological and quantitative analysis of mitochondrial DNA in MELAS.

Objectives/hypothesis: Although hearing loss is common in MELAS (syndrome of mitochondrial encephalopathy, lactic acidosis and stroke-like episodes), the histopathology of the temporal bone has not been reported. The majority of cases of MELAS are linked to a mitochondrial DNA (mtDNA) mutation at nucleotide 3243. In MELAS, normal mtDNA and mutant mtDNA coexist in a heteroplasmic manner.

Nonsyndromic hearing loss caused by a mitochondrial T7511C mutation.

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.

Phenotype of DFNA11: a nonsyndromic hearing loss caused by a myosin VIIA mutation.

Objectives/hypothesis: 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.

Study Design: 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.