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DFNA2 Nonsyndromic Hearing Loss.

Source

GeneReviews® [Internet]. Seattle (WA): University of Washington, Seattle; 1993-2017.
2008 Apr 4 [updated 2015 Aug 20].

Author information

1
Director, Molecular Otolaryngology Research Laboratories, Sterba Hearing Research Professor of Otolaryngology, Professor of Otolaryngology, Pediatrics, and Internal Medicine, Division of Nephrology, Carver College of Medicine, University of Iowa, Iowa City, Iowa
2
Department of Medicine, University of Melbourne, Melbourne, Australia

Excerpt

CLINICAL CHARACTERISTICS:

DFNA2 nonsyndromic hearing loss is characterized by symmetric, predominantly high-frequency sensorineural hearing loss (SNHL) that is progressive across all frequencies. At younger ages, hearing loss tends to be mild in the low frequencies and moderate in the high frequencies; in older persons, the hearing loss is moderate in the low frequencies and severe to profound in the high frequencies. Although the hearing impairment is often detected during routine hearing assessment of a school-age child, it is likely that hearing is impaired from birth, especially at high frequencies. Most affected persons initially require hearing aids to assist with sound amplification between ages ten and 40 years. By age 70 years, all persons with DFNA2 nonsyndromic hearing loss have severe-to-profound hearing impairment.

DIAGNOSIS/TESTING:

The diagnosis of DFNA2 nonsyndromic hearing loss is established in an individual with a characteristic audioprofile, a family history consistent with autosomal dominant inheritance, and identification of a deafness-related variant in KCNQ4.

MANAGEMENT:

Treatment of manifestations: Hearing aids for those with mild-to-moderate hearing loss; consideration of cochlear implants when hearing loss is severe to profound; special assistance in school for hearing-impaired children and adolescents. Surveillance: At least annual audiogram to follow progression of hearing loss. Agents/circumstances to avoid: Avoiding exposure to loud noise may reduce the rate of progression of high-frequency SNHL. Evaluation of relatives at risk: Determining in infancy or early childhood whether a family member of the proband has inherited a deafness-related variant in KCNQ4 allows early support and management of the child and family.

GENETIC COUNSELING:

DFNA2 nonsyndromic hearing loss is inherited in an autosomal dominant manner. Most individuals with DFNA2 nonsyndromic hearing loss have a parent with hearing loss; the proportion of individuals with a de novo deafness-related variant is unknown. Each child of an individual with DFNA2 nonsyndromic hearing loss has a 50% chance of inheriting the deafness-related variant. Prenatal testing for pregnancies at increased risk is possible if the KCNQ4 deafness-related variant has been identified in a family member.

Copyright © 1993-2017, University of Washington, Seattle. GeneReviews is a registered trademark of the University of Washington, Seattle. All rights reserved.

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