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Nonsyndromic hearing loss
Reviewed by Medicinsk Expert•Last updated: 2026-10-22•Condition

Nonsyndromic hearing loss

Nonsyndromic hearing loss is a partial or total loss of hearing that occurs without other associated signs or symptoms.

Overview

Nonsyndromic hearing loss is a permanent hearing loss not associated with other physical signs or symptoms. It is often classified by its inheritance pattern: autosomal dominant (DFNA), autosomal recessive (DFNB), X-linked (DFNX), or mitochondrial.

Symptoms

  • Severity: Ranges from mild (difficulty understanding soft speech) to profound (inability to hear loud noises).
  • Progression: Can be stable or progressive, worsening with age.
  • Type: Most forms are sensorineural (damage to inner ear structures). Less commonly, it is conductive (middle ear changes) or mixed.
  • Onset: Can be present at birth (congenital), occur before speech development (prelingual), or after speech development (postlingual).

Causes & Risk Factors

The causes are complex, with over 155 genes identified. Many genes are involved in the development and function of the inner ear. Common genetic causes include variants in the GJB2, STRC, KCNQ4, and TECTA genes. Environmental factors, such as medications, infections, and noise exposure, also play a significant role.

Inheritance

  • Autosomal recessive: Both copies of the gene have a pathogenic variant.
  • Autosomal dominant: One copy of the altered gene is sufficient to cause the condition.
  • X-linked: The altered gene is on the X chromosome; men and boys tend to be more severely affected.
  • Mitochondrial: Caused by variants in mitochondrial DNA, following a maternal inheritance pattern.

Some cases are sporadic, and others are caused by environmental factors, which are not inherited.

Frequently Asked Questions

thorough history (family hearing patterns, prenatal exposures, infections, ototoxic medications) combined with audiometric testing helps. If there is a family history of similar loss, especially across generations, or if the loss is present at birth without known exposures, a genetic cause is more likely and warrants genetic testing.
comprehensive hereditary hearing loss panel (often using next‑generation sequencing) screens the most common genes (e.g., GJB2, STRC, KCNQ4, TECTA). Results may show a pathogenic variant (confirming a genetic diagnosis), a variant of uncertain significance (requires further evaluation), or no detectable mutation (does not rule out a genetic cause).
Hearing aids are first‑line for mild‑to‑moderate loss and can be fitted once the child reliably uses them (usually after 6 months of age). Cochlear implants are considered for severe‑to‑profound loss when hearing aids provide limited benefit, typically after a trial period of at least 3‑6 months of optimal hearing‑aid use and appropriate speech‑language development assessment.
Each child of an affected parent has a 50 % chance of inheriting the dominant pathogenic variant and therefore the hearing loss, though expressivity can vary, meaning the severity may differ among affected relatives.
Source: MedlinePlus, National Library of Medicine

MedlinePlus brings together authoritative health information from the National Library of Medicine (NLM), the National Institutes of Health (NIH), and other government agencies and health-related organizations.

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