![]() Usher syndrome is inherited in an autosomal recessive pattern. People with Usher syndrome represent roughly one-sixth of people with retinitis pigmentosa. It occurs in roughly 1 person in 23,000 in the United States, 1 in 28,000 in Norway and 1 in 12,500 in Germany. The word syndrome means that multiple symptoms occur together, in this case, deafness and blindness. Usher syndrome is responsible for the majority of deaf-blindness. The genes implicated in Usher syndrome are described below. Symptoms and subtypes Usher syndrome is inherited in an autosomal recessive pattern. His observations supplied the first proofs for the coupled transmission of blindness and deafness, since no isolated cases of either could be found in the family trees. ![]() Liebreich noted that Usher syndrome is recessive, since the cases of blind-deafness combinations occurred particularly in the siblings of blood-related marriages or in families with patients in different generations. Three years later, one of his students, Richard Liebreich, examined the population of Berlin for disease pattern of deafness with retinitis pigmentosa. He reported the case of a deaf patient with retinitis pigmentosa, who had two brothers with the same symptoms. However, it was first described in 1858 by Albrecht von Gräfe, a pioneer of modern ophthalmology. Usher syndrome is named after the British ophthalmologist Charles Usher, who examined the pathology and transmission of this illness in 1914 on the basis of 69 cases. Animal models of this human disease (such as knockout mice and zebrafish) have been developed recently to study the effects of these gene mutations and to test potential cures for Usher syndrome. First recognized in the 19th century, Usher syndrome was the first condition to demonstrate that phenotypes could be inherited in tandem deafness and blindness are inherited together, but not separately. Since Usher syndrome mutations are recessive, if both parents have Usher syndrome in the same gene, all their children are overwhelmingly likely to have the same condition by contrast, the children of a mixed marriage (one parent with Usher syndrome and the other with wild-type genes) are overwhelmingly likely to not have the condition, although they will be all carriers. Consanguinity of the parents is a risk factor. Since Usher syndrome is inherited in an autosomal recessive pattern, both males and females are equally likely to inherit Usher syndrome. Usher syndrome I and II are associated with a mutation in any one of six or three different genes, respectively, whereas only one mutation has been linked with Usher III. People with Usher syndrome III are not born deaf, but experience a gradual loss of their hearing and vision they may or may not have balance difficulties. People with Usher II are also born deaf, but do not seem to have noticeable problems with balance they also begin to lose their vision later (in the second decade of life) and may preserve some vision even into middle age. They also exhibit balance difficulties and learn to walk slowly as children, due to problems in their vestibular system. People with Usher I are born profoundly deaf, and begin to lose their vision in the first decade of life. Usher syndrome has three clinical subtypes, denoted as I, II and III in decreasing order of severity. In some cases, the foveal vision is spared, leading to "doughnut vision" central and peripheral vision are intact, but there is an annulus around the central region in which vision is impaired. In other cases, there is early degeneration of the cone cells in the macula, leading to a loss of central acuity. ![]() Usually, the rod cells of the retina are affected first, leading to early night blindness and the gradual loss of peripheral vision. The hearing loss is associated with a defective inner ear, whereas the vision loss is associated with retinitis pigmentosa (rp), a degeneration of the retinal cells. This syndrome is characterized by deafness and a gradual vision loss. Usher syndrome is incurable at present however, using gene therapy to replace the missing gene, researchers have succeeded in reversing one form of the disease in knockout mice. Other names for Usher syndrome include Hallgren syndrome, Usher-Hallgren syndrome, rp-dysacusis syndrome and dystrophia retinae dysacusis syndrome. Associate Editor(s)-in-Chief: Jyostna Chouturi, M.B.B.S OverviewĪ leading cause of deaf-blindness, Usher syndrome (sometimes referred to as " Usher's syndrome") is a relatively rare genetic disorder that is associated with a mutation in any one of 10 genes.
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