Usher syndrome
Usher syndrome is an autosomal recessive disorder characterized by the presence of sensorineural deafness accompanied by retinitis pigmentosa and progressive vision loss. It accounts for 3% to 6% of cases of congenital deafness and is the most common cause of genetic deafblindness.
This disease is classified into 3 clinical types according to severity and timing of onset of symptoms. In addition, Usher syndrome is a genetically heterogeneous disorder in which 10 genes have been described that can cause it and 6 other genes that are related.
The prevalence of the syndrome is estimated at approximately 3-6.2 cases per 100,000 population.
Symptoms
Usher syndrome type I (USH1) (40% of cases): characterised by profound sensorineural deafness, bilateral vestibular areflexia or absence of response of the vestibular nerves found in the inner ear of both ears and onset of retinitis pigmentosa during adolescence.
Usher syndrome type II (USH2) (60% of cases): Sensorineural deafness occurs, ranging in severity from moderate to severe. Retinitis pigmentosa develops during the second decade of life and vestibular function is normal.
Usher syndrome type III (USH3) (<3% of cases): progressive, postlingual sensorineural deafness occurs, with onset of retinitis pigmentosa and vestibular dysfunction varying, usually from 20-30 years of age.
There are patients who may not fit this classification and are considered to have atypical Usher syndrome.
Disease management
For USH1, it is recommended to stimulate residual hearing and accustom the infant to auditory stimulation. Cochlear implantation should be considered. If families opt for nonauditory communication, educators specializing in sign language and interpreting tactile signs (once visual loss occurs) should be used.
Early hearing and speech training may be used in USH2. Also, the option of cochlear implantation should be considered for children with incomplete speech and adults with severe or profound hearing loss.
The symptoms of retinitis pigmentosa can be managed with standard treatment when they appear.
Genes analyzed
Bibliography
Castiglione A, Möller C. Usher Syndrome. Audiol Res. 2022 Jan 11;12(1):42-65.
Fuster-García C, García-Bohórquez B, Rodríguez-Muñoz A, et al. Usher Syndrome: Genetics of a Human Ciliopathy. Int J Mol Sci. 2021 Jun 23;22(13):6723.
Koenekoop RK, Arriaga MA, Trzupek KM, et al. Usher Syndrome Type I. 1999 Dec 10 [updated 2020 Oct 8]. In: Adam MP, Mirzaa GM, Pagon RA, Wallace SE, Bean LJH, Gripp KW, Amemiya A, editors. GeneReviews® [Internet]. Seattle (WA): University of Washington, Seattle; 1993-2023.
Koenekoop R, Arriaga M, Trzupek KM, et al. Usher Syndrome Type II. 1999 Dec 10 [updated 2020 Oct 22]. In: Adam MP, Mirzaa GM, Pagon RA, Wallace SE, Bean LJH, Gripp KW, Amemiya A, editors. GeneReviews® [Internet]. Seattle (WA): University of Washington, Seattle; 1993-2023.
