A neonate is found to have bilateral severe-to-profound sensorineural hearing loss on newborn hearing screening (AABR-refer). Genetic testing reveals a homozygous mutation in the GJB2 gene encoding connexin 26. Which of the following best characterizes this condition?
- A Autosomal dominant non-syndromic hearing loss; mild-to-moderate severity
- B Autosomal recessive non-syndromic hearing loss (DFNB1); often severe-to-profound ✓
- C X-linked hearing loss with progressive deterioration
- D Mitochondrial hearing loss associated with aminoglycoside sensitivity
Explanation
GJB2 (connexin 26) mutations on chromosome 13q12 are the most common cause of autosomal recessive non-syndromic sensorineural hearing loss, classified as DFNB1. It accounts for approximately 50% of autosomal recessive congenital hearing loss in many populations. The severity is typically severe-to-profound. Because it is isolated to the cochlea (connexin 26 is expressed in cochlear supporting cells but not in other sensory or neural tissues), these children are excellent cochlear implant candidates with good outcomes. Mitochondrial m.1555A>G is associated with aminoglycoside sensitivity.
Reference: Dhingra Diseases of Ear, Nose and Throat, 7th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.