Auditory dysfunction in type 2 Stickler Syndrome

• Published in: European archives of oto-rhino-laryngology 2021-07, Vol.278 (7), p.2261-2268
• Main Authors: Alexander, Philip, Gomersall, Philip, Stancel-Lewis, Jack, Fincham, Gregory Scott, Poulson, Arabella, Richards, Allan, McNinch, Annie, Baguley, David M., Snead, Martin
• Format: Article
• Language: English
• Subjects: Animals; Arthritis; Collagen Type XI - genetics; Connective Tissue Diseases; Female; Head and Neck Surgery; Hearing Loss, Sensorineural - diagnosis; Hearing Loss, Sensorineural - genetics; Medicine; Medicine & Public Health; Mice; Mutation; Neurosurgery; Otology; Otorhinolaryngology; Retinal Detachment
• ISSN: 0937-4477; 1434-4726
• DOI: 10.1007/s00405-020-06306-y

Purpose To present the extent and site of lesion of auditory dysfunction in a large cohort of individuals with type 2 Stickler Syndrome. Type 2 Stickler Syndrome results from a mutation in the gene coding for α-1 type XI pro-collagen, which has been identified in the human vitreous, cartilage and the cochlea of the mouse. The condition is characterised by classic ocular abnormalities, auditory dysfunction, osteoarthropathy and oro-facial dysplasia. Methods This is a population study which used a combination of audiometric, tympanometric, and self-report measures on a series of 65 individuals (mean age 29.2 years, range 3–70, female 63.1%) with genetically confirmed type 2 Stickler Syndrome. Results Hearing impairment was identified in at least one ear for 69% of individuals. Analysis against age-matched normative data showed that reduced hearing sensitivity was present across all test frequencies. Sensorineural hearing loss was most common (77% of ears), with conductive (3%), mixed (7%) and no hearing loss (13%), respectively. The proportion of hypermobile tympanic membranes (24%) was less than previously documented in type 1 Stickler Syndrome. When present, this appears to arise as a direct result of collagen abnormalities in the middle ear. Self-report measures of speech and spatial hearing in sound were comparable to a non-syndromic cohort with similar audiometric thresholds. Conclusions Auditory impairment in type 2 Stickler Syndrome is predominantly associated with cochlear hearing loss of varying severities across affected individuals. The impact on hearing thresholds can be seen across the frequency range, suggesting a contribution of defective collagen throughout the cochlea. Self-report questionnaires showed that difficulties understanding speech, and spatial information in sound (such as that used for localisation), were worse than a young, normal-hearing population but comparable to a non-syndromic cohort with similar audiometric thresholds. Therefore, it is likely that hearing loss in type 2 Stickler Syndrome arises in the auditory periphery, without significant central processing deficits.