Usher syndrome type III can mimic other types of Usher syndrome

Ann Otol Rhinol Laryngol. 2003 Jun;112(6):525-30. doi: 10.1177/000348940311200608.


Clinical and genetic characteristics are presented of 2 patients from a Dutch Usher syndrome type III family who have a new homozygous USH3 gene mutation: 149-152delCAGG + insTGTCCAAT. One individual (IV:1) is profoundly hearing impaired and has normal vestibular function and retinitis punctata albescens (RPA). The other individual is also profoundly hearing impaired, but has well-developed speech, vestibular areflexia, and retinitis pigmentosa sine pigmento (RPSP). These findings suggest that Usher syndrome type III can be clinically misdiagnosed as either Usher type I or II; that Usher syndrome patients who are profoundly hearing impaired and have normal vestibular function should be tested for USH3 mutations; and that RPA and RPSP can occur as fundoscopic manifestations of pigmentary retinopathy in Usher syndrome.

Publication types

  • Case Reports
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adult
  • Auditory Threshold / physiology
  • Child
  • Diagnosis, Differential
  • Electronystagmography
  • Female
  • Genotype
  • Hearing Loss, Sensorineural / diagnosis
  • Hearing Loss, Sensorineural / genetics*
  • Humans
  • Male
  • Membrane Proteins / genetics*
  • Pedigree
  • Phenotype
  • Point Mutation / genetics
  • Reflex, Abnormal / physiology
  • Reflex, Vestibulo-Ocular / physiology
  • Retinitis Pigmentosa / diagnosis
  • Retinitis Pigmentosa / genetics*
  • Syndrome
  • Vestibule, Labyrinth / physiology


  • CLRN1 protein, human
  • Membrane Proteins