ABSTRACT
Usher syndrome is the most common cause of combined neurosensory loss in the developed world. The hearing impairment is usually prelingual but the vision loss, due to retinitis pigmentosa, is gradual. The result is that more than 50% of all adults who are deaf and blind have Usher syndrome. Research into the causes of Usher syndrome has resulted in the recognition that at least 11 different genes are involved, of which six have been specifically identified. This knowledge is now proving helpful in the diagnosis of this interesting group of disorders. More important, the Usher syndromes are providing a window into the commonalities of the neurosensory processes of vision and hearing.
