Two families with phenotypically different hereditary low frequency hearing impairment: longitudinal data and linkage...

Area of Science:

• Genetics
• Otolaryngology
• Audiology

Background:

• Low-frequency hearing impairment presents diagnostic challenges.
• Previous studies identified two families with distinct inheritance patterns.

Purpose of the Study:

• To obtain longitudinal audiometric data for two families with hearing impairment.
• To clarify the mode of transmission and localize the responsible gene.
• To reevaluate genetic factors in low-frequency sensorineural hearing impairment.

Main Methods:

• Family history evaluation.
• Audiological examinations and longitudinal data collection.
• Linkage analysis for gene localization.

Main Results:

• Family A demonstrated autosomal dominant inheritance with progressive hearing loss over 13-21 years.
• Significant linkage in Family A to DFNA6 and DFNA14 loci on chromosome 4.
• Family B showed autosomal dominant inheritance with reduced penetrance and no progression.
• Family B was not linked to the chromosome 4 region, indicating genetic heterogeneity.

Conclusions:

• Autosomal dominant low-frequency hearing impairment can be progressive or non-progressive.
• Genetic linkage to chromosome 4 is identified in one family with progressive hearing loss.
• Genetic heterogeneity exists in non-syndromic low-frequency sensorineural hearing impairment.