Further delineation of the auditory phenotype in Stickler syndrome
F. Acke1, F. Swinnen1, F. Malfait2, I. Dhooge1, E. De Leenheer1
1
Department of Otorhinolaryngology, Ghent University Hospital, De Pintelaan 185, 9000
Ghent, Belgium
2
Department of Medical Genetics, Ghent University Hospital, De Pintelaan 185, 9000 Ghent,
Belgium
Introduction and aim: Otorhinolaryngologists and head/neck surgeons may be familiar with
Stickler syndrome because of cleft palate and/or hearing loss in numerous patients. Hearing
loss has received little attention due to the often more disabling ocular, orofacial and skeletal
manifestations. However, estimates suggest a global prevalence of sensorineural hearing loss
(SNHL) of up to 70%, ranging from 50% to about 100%, depending on the different
genotypes of Stickler syndrome. By performing extensive hearing tests in Stickler patients,
we want to further elucidate the auditory phenotype.
Material and methods: Molecularly confirmed Stickler patients (type 1 / type 2) were invited
to undergo an audiologically-based questionnaire, clinical examination, tympanometry,
stapedial reflex testing, pure tone audiometry, speech audiometry and oto-acoustic emissions
testing. Cross-sectional and longitudinal regression analysis of the audiograms was performed
in order to assess progression of hearing loss and to compare with age-adjusted hearing
thresholds.
Results: 20 patients (age 10-62y) out of 12 families were included. Tympanometry showed
normal middle ear pressure in 39/40 patients, but a compliance of >1.5mmho in 15/40 ears. In
type 1 Stickler syndrome (16 patients), 75% had normal low- and mid-frequency thresholds,
but 94% had high-frequency SNHL. No significant progression beyond presbyacusis was
observed. Only 1 patient had a conductive component because of otosclerosis. All type 2
Stickler patients (4) exhibited mild-to-moderate low- and mid-frequency SNHL and
moderate-to-severe high-frequency SNHL. The 50% speech reception threshold correlated
well with the pure tone average (PTA) in all patients.
Conclusions: Type 1 Stickler syndrome is characterized by a mild high-frequency SNHL,
emerging in childhood and non-progressive when controlled for presbyacusis. Patients with
type 2 Stickler syndrome exhibit early-onset, non-progressive panfrequential SNHL with a
sloping audiogram. Hypermobile tympanic membranes are a frequent finding. We
recommend regular auditory follow-up in patients with Stickler syndrome, especially during
early childhood.