Audiological manifestations in alport syndrome: a rare atypical case report

Abstract Background Alport syndrome is a hereditary disorder characterized by progressive renal dysfunction, ocular abnormalities, and bilateral sensorineural hearing loss, typically associated with mutations in type IV collagen genes. This report presents a rare and atypical case of unilateral sensorineural hearing loss in a young adult male with a confirmed COL4A5 gene mutation, contributing to the limited literature on asymmetric auditory manifestations in X-linked Alport syndrome (XLAS). Case presentation A comprehensive audiological evaluation was conducted using pure-tone audiometry, speech audiometry, immittance testing, otoacoustic emissions (OAE), and auditory brainstem response (ABR) to assess auditory function. Genetic analysis confirmed a hemizygous COL4A5 c.2137G > A variant. The subject exhibited normal hearing in the right ear and left ear was mild-to-moderate sensorineural hearing loss with a U-shaped audiometric configuration. OAEs were absent in the affected ear, indicating cochlear outer hair cell dysfunction, Click-evoked ABR revealed well-defined and replicable waveforms I, III, and V in both ears and were consistent with the pure-tone audiometry (PTA) findings, suggesting intact retrocochlear pathways. Genetic testing supported an X-linked inheritance pattern, although the identified variant was classified as a variant of uncertain significance (VUS). Family history and clinical correlation reinforced the diagnosis of XLAS. No ocular manifestations were present at the time of assessment; however, renal involvement was evident in the form of proteinuria. Conclusion This case highlights an atypical, unilateral presentation of sensorineural hearing loss in XLAS, underscoring the importance of early audiological monitoring, even in the absence of classic bilateral involvement. Audiologists play a pivotal role in the early identification and longitudinal management of hearing loss in individuals with Alport syndrome. Multidisciplinary collaboration and genetic counselling remain essential for comprehensive care.