The Usher 2A gene expresses an extra cellular matrix protein that resembles unconventional Myosin and do not appear to have any un-conventional functional correlations. It is expressed primarily in retina and cochlea and may be important in the development and homeostasis of the inner ear and retina.
The human Usher Syndrome 2A (Ush2A) protein has several functional domains (Laminin type EGF like domain; Laminin-Type epidermal growth factor like domain and a fibronectin type 3 like domain). The protein has a single transmembrane domain that anchor the protein to the cell membrane, the rest of the protein stays outside the cell.
Defects in the USH2A gene are the most common cause of deafness and blindness in adults and affect 3-6% children born with hearing impairments. The affected individuals have sensory-neural deficiencies at birth and subsequently develop progressive retinitis pigmentosa (RP). Three forms of Usher syndrome have been characterized, Usher Type 1, II and III which can be distinguish based on severity of hearing loss and vestibular involvement. Type I patents are profoundly deaf while type II (most common form of Usher syndrome) patients are mildly deaf but have normal in vestibular responses.
Cell Membrane; single-pass type I membrane protein.
Isoform 2 is secreted.