Phenotypic characterization of hereditary hearing impairment linked to XXXX .

@entity1 @entity14504 @entity47015 @entity2319 @entity1274 @entity72794 @entity14505 @entity393
OBJECTIVES: To clinically characterize a family with nonsyndromic @entity1274 linked to the @entity72794 gene and to assess whether mitochondrial mutations influence the penetrance of the phenotype. DESIGN: Longitudinal clinical and basic science molecular genetic study. SETTING: Academic medical center and molecular genetic research laboratory. @entity1 : Members of a family with dominant high-frequency @entity1274 . INTERVENTIONS: Questionnaires, serial audiograms, and interviews correlated with molecular genetic data. MAIN OUTCOME MEASURES: Symptoms, age at onset, serial audiometric data, and the presence or absence of 4 @entity2319 -associated mitochondrial mutations. RESULTS: Affected individuals typically manifest a high-frequency, slowly progressive @entity1274 in the postlingual period. The mode of inheritance is autosomal dominant with age-dependent penetrance. Male affected members tended to report an earlier onset of @entity393 than female members. In those inheriting the @entity72794 -associated haplotype from an affected mother, @entity393 invariably developed by the second decade of life, whereas those inheriting the @entity72794 haplotype from an affected father often maintained hearing levels comparable to those of age-matched control subjects, even into the seventh decade of life. None of 4 @entity2319 -associated mitochondrial mutations screened ( @entity14505 , @entity14504 , Cins7472, and @entity47015 ) were found to segregate in the family. CONCLUSIONS: It is difficult to differentiate delayed-onset high-frequency @entity1274 inherited as a simple mendelian trait like @entity72794 -associated @entity393 from that due to noise exposure or presbycusis, disorders that may also have a genetic component. An awareness of the clinical presentation of such @entity393 may help clinicians identify @entity393 attributable to genetic causes and improve care for these @entity1 .
