Genetic Underpinnings and Audiological Characteristics in Children with Unilateral Sensorineural Hearing Loss

Objective: Unilateral sensorineural hearing loss is a condition commonly encountered in otolaryngology clinics. However, its molecular pathogenesis remains unclear. This study aimed to investigate the genetic underpinnings of childhood unilateral sensorineural hearing loss and analyze the associated audiological features. Study Design: Retrospective analysis of a prospectively recruited cohort Setting: Tertiary referral center Methods: We enrolled 38 children with unilateral sensorineural hearing loss and performed physical, audiological, imaging, and congenital cytomegalovirus examinations as well as genetic testing using next-generation sequencing targeting 30 deafness genes. The audiological results were compared across different etiologies. Results: Causative genetic variants were identified in eight (21.1%) patients, including five with GJB2 variants, two with PAX3 variants, and one with EDNRB variant. GJB2 variants were associated with mild-to-moderate unilateral sensorineural hearing loss in various audiogram configurations, whereas PAX3 and EDNRB variants were associated with profound unilateral sensorineural hearing loss in flat audiogram configurations. In addition, whole genome sequencing and extended next-generation sequencing targeting 213 deafness genes were performed in two multiplex families compatible with autosomal recessive inheritance; yet no definite causative variants were identified. Cochlear nerve deficiency and congenital cytomegalovirus infection were observed in nine and two patients without definite genetic diagnoses. Conclusion: Genetic underpinnings can contribute to approximately 20% of childhood unilateral sensorineural hearing loss, and different genotypes are associated with various audiological features. These findings highlight the utility of genetic examinations in guiding the diagnosis, counseling, and treatment of unilateral sensorineural hearing loss in children.