Audiological and surgical evidence for the presence of a third window effect for the conductive hearing loss in DFNX2 deafness irrespective of types of mutations
The objective of this study was to clarify the cause of the air–bone gap in incomplete partition (IP) type III cases according to the POU3F4 gene (DFNX2) mutation type. A retrospective analysis of patient medical records was done in a tertiary referral medical center. Five IP type III patients prove...
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Published in | European archives of oto-rhino-laryngology Vol. 270; no. 12; pp. 3057 - 3062 |
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Main Authors | , , , , , , , , , |
Format | Journal Article |
Language | English |
Published |
Berlin/Heidelberg
Springer Berlin Heidelberg
01.11.2013
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Subjects | |
Online Access | Get full text |
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Summary: | The objective of this study was to clarify the cause of the air–bone gap in incomplete partition (IP) type III cases according to the
POU3F4
gene (DFNX2) mutation type. A retrospective analysis of patient medical records was done in a tertiary referral medical center. Five IP type III patients proved to be carrying a mutation in or affecting
POU3F4
. The hearing and the middle ear status at either exploratory tympanotomy or cochlear implantation from these DFNX2 cases was reviewed. Four of five unrelated IP type III patients harbored a point mutation of
POU3F4
and the fifth patient carried a large genomic deletion upstream to
POU3F4
. Two of the four DFNX2 patients carrying a point mutation had moderate to severe mixed hearing loss with a substantial amount of air–bone gap. These patients underwent exploratory tympanotomy to identify the cause of their hearing loss. The other three patients, including one carrying a large deletion, had profound hearing loss at presentation and received a cochlear implant. In the exploratory tympanotomy group with a substantial amount of air–bone gap and a point mutation (
n
= 2), one patient had a perfect ossicular chain with normal mobility, a positive ipsilateral stapedial reflex, and a positive round window reflex. In the cochlear implantation group (
n
= 3), we found a stapes with normal mobility and a positive round window reflex in one patient who harbored a large genomic deletion upstream to
POU3F4
. We concluded that the probable presence of the third window effect is not limited to the particular type of
POU3F4
mutation. |
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ISSN: | 0937-4477 1434-4726 |
DOI: | 10.1007/s00405-013-2386-3 |