Related Experiment Video
Updated: Jul 1, 2026
05:55
Dextran Labeling and Uptake in Live and Functional Murine Cochlear Hair Cells
Published on: February 8, 2020
A catechol-O-methyltransferase that is essential for auditory function in mice and humans
Xin Du1, Martin Schwander, Eva Marie Y Moresco
1Department of Genetics, Institute for Childhood and Neglected Diseases, The Scripps Research Institute, La Jolla, CA 92037, USA.
Summary
Researchers discovered a new gene, catechol-O-methyltransferase 2 (COMT2), crucial for hearing and balance. Mutations in COMT2 cause deafness and vestibular issues in mice and humans, revealing a novel role for catecholamines in sensory organ function.
Area of Science:
- Neuroscience
- Genetics
- Otolaryngology
Background:
- Catechol-O-methyltransferase (COMT) enzymes are known to be involved in neurotransmitter metabolism, with implications in psychiatric disorders like schizophrenia.
- The specific role of COMT in sensory systems, particularly auditory and vestibular functions, remains largely unexplored.
Purpose of the Study:
- To identify and characterize a novel catechol-O-methyltransferase gene (COMT2) involved in neurobehavioral and sensory phenotypes.
- To investigate the function of COMT2 in the auditory and vestibular systems.
- To determine the genetic basis of deafness and vestibular impairment linked to COMT2 dysfunction.
Main Methods:
- Positional cloning of a chemically induced mutation in mice to identify the responsible gene.
- Phenotypic analysis of mice with a missense mutation in the Comt2 gene, including assessment of vestibular function and auditory capabilities.
- Histological examination of the organ of Corti in affected mice.
- Enzymatic activity assays to evaluate the impact of the mutation on COMT2 function.
- Genetic screening of human families to identify mutations in the human ortholog of Comt2.
Main Results:
- Identification of a previously unannotated gene, COMT2, through positional cloning in mice.
- Mice with a missense mutation in Comt2 exhibited vestibular impairment, profound sensorineuronal deafness, and degeneration of the organ of Corti.
- COMT2 is highly expressed in sensory hair cells of the inner ear, and the mutation significantly reduced its enzymatic activity.
- A nonsense mutation in the human COMT2 gene was identified in a family with nonsyndromic deafness.
- These findings suggest a critical role for catecholamine catabolism by COMT2 in auditory and vestibular function.
Conclusions:
- A novel gene, COMT2, has been identified, playing a critical role in auditory and vestibular sensory organ function.
- Defects in COMT2 are causally linked to sensorineuronal deafness and vestibular impairment in both mice and humans.
- This research uncovers an unexpected function of catecholamines in the maintenance and operation of the inner ear's sensory systems.
