One of several diseases associated with defects in the human gene MYO7A, an unconventional myosin. See human disease model report for Usher syndrome, deafness, MYO7A-related (FBhh0000472). OMIM includes this disease in the phenotypic series Usher syndrome (FBhh0000466).
[updated Jan. 2017 by FlyBase; FBrf0222196]
Usher syndrome is a condition characterized by partial or total hearing loss and vision loss that worsens over time. The hearing loss is classified as sensorineural, which means that it is caused by abnormalities of the inner ear. The loss of vision is caused by a type of retinitis pigmentosa (RP), which affects the layer of light-sensitive tissue in the retina. [from Genetics Home Reference, Usher syndrome; 2017.01.09]
Usher syndrome is characterized by congenital hearing impairment and varying degrees of unintelligible speech, early retinitis pigmentosa, and vestibular dysfunction; autosomal recessive inheritance is usually observed. Type I is distinguished from type II on the basis of severity of hearing loss and the extent of vestibular involvement. Type I patients are profoundly deaf, whereas type II patients are 'hard of hearing.' Vestibular function is defective in type I patients, whereas type II patients have normal vestibular function (Moller et al., 1989; pubmed:2909824). Patients with type III have progressive hearing loss. [from MIM:601067; 2017.01.09]
[USHER SYNDROME, TYPE I; USH1](https://omim.org/entry/276900)
[MYOSIN VIIA; MYO7A](https://omim.org/entry/276903)
Usher syndrome type I is an autosomal recessive condition characterized by profound congenital hearing impairment with unintelligible speech, early retinitis pigmentosa (usually evident within the first decade), and constant vestibular dysfunction. [from MIM:276900; 2017.01.09]
Usher syndrome type I (USH1) is caused by homozygous or compound heterozygous mutation in the gene encoding myosin VIIA (MYO7A) (autosomal recessive). [from MIM:276900; 2017.01.09]
The MYO7A gene encodes a protein classified as an unconventional myosin. Unconventional myosins are motor molecules with structurally conserved heads that move along actin filaments. Their highly divergent tails are presumed to be tethered to different macromolecular structures that move relative to actin filaments, thus enabling them to transport cargo (Weil et al., 1995; pubmed:7870171). [from MIM:276903; 2017.01.09]
Many to many: 2 human to 2 Drosophila; the other human gene is MYO7B.
