Audiometric characteristics of two Dutch families with non-ocular Stickler syndrome (COL11A2).
OBJECTIVE
To evaluate hearing impairment and cochlear function in non-ocular Stickler syndrome.


METHODS
Multifamily study.


METHODS
Ten patients from two different families with non-ocular Stickler syndrome (Stickler syndrome type 3) were included. Six members of the first family and four members of the second family participated in this study. Otorhinolaryngologic examinations were performed. Pure-tone and speech audiograms were obtained. Longitudinal analysis was performed. Psychophysical measurements, including loudness scaling, gap detection, difference limen for frequency and speech perception in noise were administered to assess cochlear function at a deeper level.


RESULTS
Affected individuals in the first family were carriers of a heterozygous splice donor mutation in the COL11A2 gene. Affected individuals in the second family were carriers of a novel heterozygous missense mutation in COL11A2. Both families showed bilateral, non-progressive hearing impairment with childhood onset. The severity of the hearing impairment exhibited inter- and intrafamilial variability and was mostly mild to moderate. The results of the psychophysical measurements were similar to those previously published for DFNA8/12 (TECTA) and DFNA13 (COL11A2) patients and thus consistent with an intra-cochlear conductive hearing impairment. This is in line with the theory that mutations in COL11A2 affect tectorial membrane function.


CONCLUSIONS
Hearing impairment in non-ocular Stickler syndrome is characterized by non-progressive hearing loss, present since childhood, and mostly mild to moderate in severity. Psychophysical measurements in non-ocular Stickler patients were suggestive of intra-cochlear conductive hearing impairment.
Department of Otorhinolaryngology, Head and Neck Surgery, Radboud University Nijmegen Medical Centre, P.O. Box 9101, 6500 HB Nijmegen, The Netherlands. E.vanBeelen@kno.umcn.nl
E
E
van Beelen
J M
JM
Leijendeckers
P L M
PL
Huygen
R J C
RJ
Admiraal
L H
LH
Hoefsloot
K D
KD
Lichtenbelt
L
L
Stöbe
R J E
RJ
Pennings
R
R
Leuwer
A F M
AF
Snik
H P M
HP
Kunst
D001168:Arthritis / Q000235:genetics* / Q000503:physiopathology* / Q000523:psychology; D001301:Audiometry, Pure-Tone; D001302:Audiometry, Speech; D024161:Collagen Type XI / Q000235:genetics*; D003240:Connective Tissue Diseases / Q000235:genetics* / Q000503:physiopathology* / Q000523:psychology; D005260:Female; D015870:Gene Expression; D006314:Hearing Loss, Conductive / Q000235:genetics* / Q000503:physiopathology* / Q000523:psychology; D006579:Heterozygote; D006801:Humans; D008297:Male; D009154:Mutation; D009426:Netherlands; D010375:Pedigree; D010641:Phenotype; D011571:Psychoacoustics; D013680:Tectorial Membrane / Q000503:physiopathology
C499319:COL11A2 protein, human; D024161:Collagen Type XI