Children with GJB2 gene mutations have various audiological phenotypes

Area of Science:

• Genetics
• Audiology
• Pediatrics

Background:

• GJB2 gene mutations are a common cause of congenital hearing loss.
• Phenotypic variability exists in children with GJB2 mutations, impacting audiological outcomes.
• Understanding these variations is crucial for early diagnosis and intervention.

Purpose of the Study:

• To investigate audiological phenotype variations in children with GJB2 gene mutations.
• To compare hearing loss characteristics between biallelic truncating (T/T) and truncating/nontruncating (T/NT) GJB2 mutations.
• To analyze results of universal newborn hearing screening (UNHS) and hearing loss degree/symmetry.

Main Methods:

• Retrospective study of 128 pediatric outpatients with GJB2 mutations at Beijing Tongren Hospital (2012-2018).
• Categorization into T/T (99 subjects) and T/NT (29 subjects) mutation groups.
• Examination of genotypes, UNHS results, and hearing loss characteristics (degree and symmetry).

Main Results:

• 20.37% of subjects passed UNHS; 13 with T/T and 9 with T/NT mutations.
• Severe-to-profound hearing loss was prevalent in T/T group (73.23%), while normal hearing was common in T/NT group (41.38%).
• Symmetrical hearing loss was the main phenotype in both groups, but 36.53% had bilateral asymmetric hearing loss.

Conclusions:

• Children with GJB2 gene mutations exhibit significant phenotypic variability in hearing outcomes.
• T/NT mutations are associated with better UNHS results and milder hearing loss compared to T/T mutations.
• Symmetrical hearing loss is common, but asymmetric patterns also occur, highlighting the need for comprehensive audiological assessment.