====== Usher Syndrome ======
often abbreviated as USH

====Main Features====
  * Retinitis Pigmentosa
  * Sensorineural hearing loss
  * Vestibular disturbances

====Eye Findings====
  * Retinitis Pigmentosa
    * Pigmentary retinopathy with degeneration of the RPE
    * Optic disc pallor
    * Retinal arteriolar attenuation
    * Symptoms
      * Decreased visual acuity 
      * Nyctalopia
      * Peripheral visual field deterioration

====Other Findings====
  * Progressive retinal degeneration, course depends on the gene affected
    * USH type 1 = profound congenital hearing loss and early vision loss (most severe)
    * USH type 2 = RP by the second decade, moderate to severe congenital hearing loss and no vestibular abnormalities (most severe)
    * USH type 3 = Progressive and variable hearing loss, RP and vestibular abnormalities
    * Significant overlap among subtypes
====Etiology====
  * Autosomal Recessive inheritance
  * Included in the category of ciliopathy
    * abnormal formation of cilia 
  * Major genes affected
    * USH1 genes 
      * MYO7A, USH1C, PDCH15, CDH23, USH1G
    * USH2 genes
      * USH2A, ADGRV1, WHRN
    * USH3 gene- CLRN1
  * Other genes implicated but need classification 
  * Usher genes encode for proteins expressed in the inner ear and retina where they provide essential functions for the development of sensory hair cells and photoreceptor maintenance

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**From Resource (1)**

====Epidemiology====
  * Prevalence 
    * Worldwide 4-17 per 100,000 
    * USA 4.4 per 100,000
  * Most common cause for hereditary deafness and blindness 
    * 5% of all congenital deafness
    * 18% of retinitis pigmentosa cases 

====Resources====
  - {{::the_genetic_and_phenotypic_landscapes_of_usher_syndrome-from_disease_mechanisms_to_a_new_classification-review_2022.pdf|Delmanghani S et al. The genetic and phenotypic landscapes of Usher syndrome: from disease mechanisms to a new classification. Human Genetics 2022;141:709-735}}

{{tag>syndrome}}