Auditory dysfunction in Stickler syndrome

Objectives: To characterize the natural history and possible mechanisms of hearing loss in Stickler syndrome (OMIM 108300; or hereditary progressive a rthroophthalmopathy) and to determine if the auditory phenotype is a useful discriminating feature for the differential diagnosis of this group of dis orders. Design: Multifamily study. Setting: Outpatient audiology and otolaryngology clinics at the Warren Gran t Magnuson Clinical Center of the National Institutes of Health, Rockville, Md. Subjects: Forty-six affected individuals from 29 different families segrega ting Stickler syndrome. Interventions: Clinical audiologic and otolaryngological examinations were performed on all individuals, including pure-tone audiometry, speech audiom etry, and middle ear immittance testing. Otoacoustic emissions, auditory br ainstem response, infrared video electronystagmography, and temporal bone c omputed tomography were performed on a subset of participants. Results: The hearing loss was most often sensorineural in adults, and appro ximately 28 (60%) of the 46 adult patients had 2 or more thresholds greater than the corresponding 95th percentile values for an age-matched, otologic ally normal population. The hearing loss most often affected high frequenci es (4000-8000 Hz) and was generally no more progressive than that due to ag e-related hearing loss. Type A(D) tympanograms (classification using the Je rger model), indicating hypermobile middle ear systems, were observed in 21 (46%) of the 46 affected individuals. Computed tomography of the temporal bones revealed no inner ear malformations in 19 affected individuals. Conclusions: The hypermobile middle ear systems observed in ears with norma l-appearing tympanic membranes represent a novel finding for Stickler syndr ome and are likely to be a useful diagnostic feature for this disorder. The overall sensorineural hearing loss in type I Stickler syndrome is typicall y mild and not significantly progressive. It is less severe than that repor ted for types II and III Stickler syndrome linked to COL11A2 (OMIM 120290) and COL11A1 (OMIM 120280) mutations, respectively, or the closely related M arshall syndrome. This difference will be a useful discriminatory feature i n the differential diagnosis of this group of disorders.