====== 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
    * USH1B (MYO7A)
    * USH1C
    * CDH23
    * USH 1F (PCDH15)
    * USH2A
    * USH3A
  * 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
====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 

====Reference====
  * [[link|Title]]

{{tag>syndrome}}