Characteristics of hearing loss in patients with COL2A1 gene variants (sticker syndrome type 1)

Abstract

Stickler syndrome type 1 (STL1) is an autosomal dominant genetic disorder that affects connective tissue with highly heterogeneous clinical manifestations, primarily at the ocular, orofacial, skeletal, and auditory levels. The aim of our study was to determine the variability of the auditory phenotype associated with pathogenic variants of the COL2A1 gene and its impact on long-term treatment and follow-up. A retrospective observational study was conducted on patients with a confirmed diagnosis of STL1 treated between 2018 and 2024 at the Otorhinolaryngology Department of the Marqués de Valdecilla University Hospital. The electronic medical records of the patients included in the study were reviewed to gather the following information: family history, age, sex, genetic variant of STL1, audiological test data, associated clinical manifestations, radiological tests, and treatment. Among the 8 patients included in the study, 6 (75%) exhibited hearing loss, with severity ranging from mild to profound. Of these, 4 (66.7%) had sensorineural hearing loss, 1 (16.7%) had conductive hearing loss, and 1 (16.7%) had a mixed type. The 4 patients with sensorineural hearing loss required hearing aid fitting, and one of them also needed a cochlear implant, showing significant improvement in language comprehension. Another patient required a mastoidectomy due to a cholesteatoma. The results of our study suggest that hearing loss in patients with STL1 is a common finding, predominantly sensorineural in nature and of variable intensity.