USH2A gene

The official name of USH2A gene is Usher syndrome 2A (autosomal recessive, mild)..The USH2A gene provides instructions for making anan enzyme called usherin. Usherin is an important component of basement membranes, which are thin sheet-like structures that separate and support cells in many tissues. Usherin is found in the inner ear and the part of the eye that detects light and color (the retina). Although the function of usherin has not been well established, studies suggest that this protein is part of a larger protein complex that plays an important role in inner ear and retinal development. In these locations, the protein complex may also be involved in the function of synapses, which are junctions between nerve cells where cell-to-cell communication occurs.

Location:

USH2A gene is present in human chromosome 1 and ts coded from region 213,862,858 to 214,663,360 complement with 71 exons, the cytogenetic location 1q41.

Disease

Mutations in USH2A gene causes a form of  Usher syndrome type IIA,Usher syndrome is a condition characterized by hearing loss or deafness and progressive vision loss. The loss of vision is caused by an eye disease called retinitis pigmentosa (RP), which affects the layer of light-sensitive tissue at the back of the eye (the retina). Vision loss occurs as the light-sensing cells of the retina gradually deteriorate.Mutations change single protein building blocks (amino acids) in the usherin protein. In some cases, these mutations lead to the production of an abnormally short version of the protein or prevent the cell from making any functional usherin. Other mutations insert or delete small amounts of DNA in the USH2A gene, which probably impairs the normal function of usherin. Researchers have not determined how a missing or altered usherin protein leads to the signs and symptoms of Usher syndrome.The most common mutation in the USH2A gene is found in about 25 percent of people with Usher syndrome type IIA, particularly those from Europe, the United States, South Africa, and China. This mutation deletes a specific DNA building block, a guanine (G) nucleotide, at position 2299 in the USH2A gene (written as 2299delG). Individuals with this change, or with similar mutations in the USH2A gene, develop moderate to severe hearing loss and retinitis pigmentosa, a disorder that results in loss of vision.