Related Experiment Video
Updated: Jun 7, 2026
03:42
High-Speed Human Temporal Bone Sectioning for the Assessment of COVID-19-Associated Middle Ear Pathology
Published on: May 18, 2022
Extralabyrinthine manifestations of DFNA9
Andrew A McCall1, Fred H Linthicum, Jennifer T O'Malley
1Department of Otolaryngology, Massachusetts Eye and Ear Infirmary, 243 Charles Street, Boston, MA 02114, USA. mccallaa@upmc.edu
Journal of the Association for Research in Otolaryngology : JARO
|November 6, 2010
Summary
Mutations in the COCH gene cause DFNA9 hearing loss. New extralabyrinthine deposits found in the middle ear suggest varied deposit composition in DFNA9 patients.
Area of Science:
- Otolaryngology
- Genetics
- Histopathology
Background:
- DFNA9 is an autosomal dominant disorder causing sensorineural hearing loss and vestibular dysfunction.
- It is linked to mutations in the COCH gene and previously known for intralabyrinthine histopathologic features.
- This study investigates potential extralabyrinthine findings in DFNA9.
Purpose of the Study:
- To identify and characterize novel extralabyrinthine histopathologic findings in DFNA9.
- To compare the composition of extralabyrinthine deposits with intralabyrinthine deposits.
- To discuss the implications of these findings for DFNA9 diagnosis and understanding.
Main Methods:
- Histopathologic review of 12 temporal bones from seven individuals with DFNA9.
- Comparison with age-matched control temporal bones.
- Analysis using Hematoxylin and eosin stain and Movat's pentachrome stain, including immunomarkers for cartilage components.
Main Results:
- Abnormal deposits were consistently found in the tympanic membrane, incudomalleal joint, and incudostapedial joint in DFNA9 temporal bones.
- Extralabyrinthine deposits showed different staining patterns compared to intralabyrinthine deposits.
- Tympanic membrane deposits resembled cartilage and stained for aggrecan, but lacked chondrocyte markers.
Conclusions:
- DFNA9 is associated with previously unrecognized extralabyrinthine deposits in the middle ear.
- The composition of these deposits may vary by location within the temporal bone.
- These findings may influence the clinical presentation and diagnostic approach for adult-onset hearing loss.
