The commonest genetic cause of nonsyndromic congenital sensorineural hearing loss is a mutation in:
- A GJB2 gene encoding connexin 26 ✓
- B MYO7A gene encoding myosin VIIA
- C COCH gene encoding cochlin
- D OTOF gene encoding otoferlin
Correct answer: A. GJB2 gene encoding connexin 26
Explanation
Mutations in GJB2 (locus DFNB1) encoding the gap junction protein connexin 26 account for up to half of autosomal recessive nonsyndromic congenital SNHL worldwide, making it the single commonest genetic cause. MYO7A causes Usher type 1B and DFNA2 phenotypes, COCH causes late-onset progressive loss with vestibular signs, and OTOF causes auditory synaptopathy, all far less frequent than GJB2.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.