Usher syndrome is a rare inherited disorder primarily characterized by deafness due to an impaired ability of the auditory nerves to transmit sensory input to the brain (sensorineual hearing loss) accompanied by retinitis pigmentosa, a disorder that causes progressive loss of vision. Researchers have identified three types of Usher syndrome and debated the existence of a fourth type. The age at which the disorder appears along with the severity of symptoms distinguishes the different types of Usher syndrome. Usher syndrome is inherited as an autosomal recessive genetic trait. The possible fourth type of Usher syndrome may be inherited as an X-linked genetic trait.
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