Hearing Outcomes in Stickler Syndrome: Variation Due to COL2A1 and COL11A1

Objectives: Stickler syndrome (SS) is a heterogeneous inherited connective tissue disorder, often due to a mutation in COL2A1 or COL11A1. Mutations in these genes cause collagen abnormalities affecting ocular, auditory, orofacial, and skeletal systems, including hearing loss, micrognathia, and cleft palate. Understanding the variability of hearing phenotypes based on genetic mutation has a significant impact on treatment and long-term care. Design: A retrospective chart review of pediatric patients with a confirmed diagnosis of SS between January 2003 and December 2018 at a tertiary pediatric hospital was performed. Patients were excluded if they did not have genetic evaluation, craniofacial/ear, nose, and throat evaluation, and/or audiologic testing. Charts were reviewed for the following information: age, race, sex, SS diagnosis, genetic variant of SS, and audiological testing data. Results: There were 29 confirmed patients with SS who met criteria, 16 with type I (COL2A1) and 13 with type II (COL11A1). Of the 13 patients with type II, 12 (92%) demonstrated hearing loss, ranging in severity from mild to severe. In type I, 25% of patients had mild or resolved hearing loss. Conclusion: Results suggest that patients with type II SS are more likely to have congenital hearing loss than type I. Data also suggest that the COL11A1 mutation shows consistently more severe hearing loss than the COL2A1 mutation.