Usher syndrome is a genetic disease causing deaf-blindness. It is essentially progressive retinitis pigmentosa combined with congenital hearing impairment. It is almost always inherited in an autosomal recessive pattern and is estimated to occur in 1 in 10,000 people. Whilst this is a rare genetic condition, it represents the major cause of syndromic deafness with blindness. The condition gets its name from British ophthalmologist, C.H. Usher, who in 1914 wrote a paper describing several cases in which the link between congenital deafness and retinitis pigmentosa was stressed. Deafblindness (or deaf-blindness) is the condition of a person who is both deaf and blind. ... Normal vision. ... To meet Wikipedias quality standards, this article or section may require cleanup. ... In genetics, the term recessive gene refers to an allele that causes a phenotype (visible or detectable characteristic) that is only seen in a homozygous genotype (an organism that has two copies of the same allele). ...

Usher syndrome is divided into three types, I, II and III. Children with type I syndrome are born profoundly deaf, and eyesight usually begins degrading after the first decade of life, beginning with night-blindness. If identified at a young age, children usually receive a cochlear implant, and generally learn spoken language. Sign language is also sometimes used, though when vision loss becomes severe one must revert to tactile signing. Problems with balance are usually present, due to the failure of the hair cells of the inner ear. Type II children are hard-of-hearing, and changes in sight usually begin later, first becoming noticeable after the second decade of life. In the type III syndrome, hearing loss as well as retinitis pigmentosa can occur later in life. The word deaf, can have very different meanings based on the background of the person speaking or the context in which the word is used. ... Nyctalopia (literally night blindness) is a condition making it difficult or impossible to see in the dark. ... Illustration of a cochlear implant A Cochlear implant is a device implanted in the inner ear to restore hearing by stimulating nerves inside the cochlea. ... A sign language (also signed language) is a language which uses manual communication instead of sound to convey meaning - simultaneously combining handshapes, orientation and movement of the hands, arms or body, and facial expressions to fluidly express a speakers thoughts. ... Tactile signing is a common means of communcation used by people with both a vision and hearing impairment (see Deafblindness), which is based on a standard system of Deaf manual signs. ... For other meanings of the word balance, see: propaganda equilibrium (disambiguation page) sense of balance weighing scale analytical balance (a precise weighing scale) balance beam in gymnastics Balance (song) homeostasis, the biological balance within a human or other animals body When the weights on the plates of this balance... Hair cells are the sensory cells of the auditory system that are found within the cochleas organ of Corti. ... An ear is an electric organ (much like a grand piano or keyboard) used by an animal to detect sound waves. ... This article is about hearing impairment in the pathological sense. ...

Usher syndrome I

Worldwide, the estimated prevalence of Usher syndrome type I is 3 to 6 per 100,000 people in the general population.

Mutations in the CDH23, MYO7A, PCDH15, Usher 1C (also known as Harmonin), and USH1G (now identified as SANS) genes cause Usher syndrome type I. Usher syndrome type I can be caused by mutations in one of several different genes. These genes function in the development and maintenance of inner ear structures such as hair cells (stereocilia), which transmit sound and motion signals to the brain. Alterations in these genes can cause an inability to maintain balance (vestibular dysfunction) and hearing loss. The genes also play a role in the development and stability of the retina by influencing the structure and function of both the rod photoreceptor cells and supporting cells called the retinal pigmented epithelium. Mutations that affect the normal function of these genes can result in retinitis pigmentosa and vision loss. This article has been identified as possibly containing errors. ... The official name of the gene Usher 1c is “Usher syndrome 1C (autosomal recessive, severe). ... For an alternative meaning, see ear (botany). ... Hair cells are the sensory cells of both the auditory system and the vestibular system in all vertebrates. ... Stereocilia are mechanosensing organelles of hair cells, which respond to fluid motion or fluid pressure changes in numerous types of animals for numerous functions. ... A schematic representation of hearing. ... In physics, motion means a change in the position of a body with respect to time, as measured by a particular observer in a particular frame of reference. ... Comparative brain sizes In animals, the brain, or encephalon (Greek for in the head), acts as the control center of the central nervous system. ... Human eye cross-sectional view. ... Normal vision. ...

Usher syndrome II

Usher syndrome type II occurs at least as frequently as type I, because type II may be underdiagnosed or more difficult to detect, it could be up to three times as common as type I.

Mutations in the MASS1 (also called VLGR1) and USH2A genes cause Usher syndrome type II. Usher syndrome type II may be caused by mutations in any of three different genes, two of which have been identified to date. These genes are called USH2A and MASS1. Usherin, the protein made by the USH2A gene, is located in supportive tissue in the inner ear and retina. Usherin is critical for the proper development and maintenance of these structures, which may help explain its role in hearing and vision loss. The precise function of the protein made by the MASS1 gene is not yet known. This article has been identified as possibly containing errors. ... A representation of the 3D structure of myoglobin, showing coloured alpha helices. ... For an alternative meaning, see ear (botany). ... Human eye cross-sectional view. ...

Usher syndrome III

The frequency of Usher syndrome type III is highest in the Finnish population, but it has been noted rarely in a few other ethnic groups.

Mutations in the USH3A gene cause Usher syndrome type III. Usher syndrome type III can be caused by mutations in one of at least two genes, only one of which (USH3A) has been identified. The USH3A gene makes a protein that is important for the development and maintenance of the inner ear and retina. The protein's function in these structures, and its role in hearing and vision loss, have not yet been fully explained. "Mrs. Ris sucks major penis, no wait slash that, MONSTER PENIS"

 -Kazuyuki Tsubaki 

External links

• Boys Town National Research Hospital
• The Williams retinal Physiology Research Group, UCSD

This article incorporates public domain text from The U.S. National Library of Medicine