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Hearing Disorders

7 conditions|5 ABGC-listed

Overview

Genetic hearing loss is extremely common (~1/500 newborns). A useful framework classifies hearing loss along two axes: type (sensorineural vs conductive) and etiology (genetic vs environmental). This 2x2 grid helps organize the differential.

Hearing loss framework
Hearing loss framework

Key concepts:

  • ~50% of congenital hearing loss is genetic
  • GJB2 variants are the most common cause of genetic hearing loss
  • Syndromic vs. non-syndromic (70% of genetic hearing loss is non-syndromic)
  • Conductive vs. sensorineural

Genetic Hearing Loss

Non-syndromic hearing loss accounts for ~70% of genetic hearing loss, with GJB2 being the most common cause, including ethnic-specific variants. For syndromic hearing loss, the associated features distinguish them: Usher (retinitis pigmentosa), Waardenburg (pigmentary changes), Pendred (thyroid/EVA), and BOR (branchial/renal). Jervell and Lange-Nielsen adds cardiac risk, so an ECG is indicated in children with congenital SNHL.

Branchio-oto-renal syndrome (BOR)

ABGC

A child with hearing loss is noted to have preauricular pits, branchial cleft cysts, and cupped ears. Renal ultrasound reveals bilateral renal hypoplasia.

GJB2-related hearing loss (Connexin 26)

ABGC

A newborn fails the newborn hearing screen. Audiologic evaluation confirms bilateral severe-to-profound sensorineural hearing loss. Physical exam is normal. Genetic testing reveals two pathogenic variants in *GJB2*.

Hereditary hearing loss (overview)

ABGC

A 2-day-old newborn fails the universal newborn hearing screen (OAE) bilaterally. Follow-up ABR confirms bilateral moderate-to-severe sensorineural hearing loss. Physical exam is unremarkable with no dysmorphic features, no pigmentary anomalies, and no branchial or renal abnormalities. Family history is negative. Genetic testing with a hearing loss panel is recommended.

Jervell and Lange-Nielsen syndrome

A child with congenital profound sensorineural hearing loss has syncopal episodes during exercise. ECG reveals a markedly prolonged QTc interval of 550 ms.

Pendred syndrome

ABGC

A child with bilateral sensorineural hearing loss is found to have enlarged vestibular aqueducts on CT imaging. Thyroid function is normal in childhood, but a perchlorate discharge test is abnormal.

Usher syndrome

ABGC

A 10-year-old with congenital profound hearing loss begins to have difficulty seeing at night. Ophthalmologic exam reveals retinitis pigmentosa. He also has vestibular dysfunction.

Waardenburg syndrome

A child with unilateral sensorineural hearing loss has bright blue eyes with heterochromia (one blue, one brown), a white forelock, and widely spaced inner canthi.

Summary Table

DisorderGeneInheritanceCardinal Features
GJB2GJB2ARNon-syndromic SNHL, most common genetic cause
Usher type 1MYO7A, othersARProfound HL + RP + vestibular dysfunction
Usher type 2USH2AARModerate HL + RP, normal vestibular
WaardenburgPAX3, othersADHL + pigmentary changes + dystopia canthorum
PendredSLC26A4ARSNHL + enlarged vestibular aqueduct + goiter
JLNSKCNQ1ARProfound SNHL + long QT
BOREYA1ADBranchial cysts + HL + renal anomalies
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