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myosin-associated deafness
Saturday 3 June 2006
Types
| MYO1A | ||||
| MYO3A | ||||
| MYO6 | ||||
| MYO7A | ||||
| MYH9 | MIM.160775 | 22q11.2 | deafness DFNA17 | MIM.603622 |
| MYH14 | ||||
| MYO15A |
Physiopathology
Specific myosins are implicated in sensory transduction.
Mutations in the genes encoding myosin-VI and myosin-VIIa have been linked to several disorders characterized by deafness in humans.
The strongest evidence of a defect in vesicular transport in this group of diseases is found in Usher syndrome type 1B, which is caused by mutations in the gene for myosin-VIIa.
In addition to deafness, patients with this syndrome have retinitis pigmentosa, which leads to blindness.
Myosin-VIIa is abundant in the synaptic regions of photoreceptor cells and presumably acts as an actin-based motor protein involved in the formation and transport of the ribbon-synaptic vesicle complexes characteristic of these sensory cells.
Furthermore, myosin-VIIa may be involved in the renewal of the outer photoreceptor disks, a process requiring efficient membrane transport, and in endocytic transport in cochlear hair cells.
See also
myosins
vesicula transport (vesicle transport)
deafness
- cadherin-associated deafness
References
Olkkonen VM, Ikonen E. Genetic defects of intracellular-membrane transport. N Engl J Med. 2000 Oct 12;343(15):1095-104. PMID: 11027745
Gibson F, Walsh J, Mburu P, et al. A type VII myosin encoded by the mouse deafness gene shaker-1. Nature 1995;374:62-64.
