Clinical findings in obligate carriers of type I Usher syndrome

M. Wagenaar, B. Ter Rahe, A. Van Aarem, P. Huygen, R. Admiraal, E. Bleeker- Wagemakers, A. Pinckers, W. Kimberling, C. Cremers

Research output: Contribution to journalArticlepeer-review

10 Scopus citations


Seventeen obligate carriers from nine families with autosomal recessive Usher syndrome type I underwent otological, audiological, vestibular, and ophthalmological examination in order to identify possible manifestations of heterozygosity. Linkage studies were performed and six families showed linkage to chromosome region 11q13.5 while 3 families have so far failed to show linkage to the candidate regions. Eight obligate carriers had an abnormal pure-tone audiogram. Two different audiometric patterns could he distinguished when hearing loss was corrected for age and sex. Four carriers (24%) had significant sensorineural hearing loss (SNHL) which increased at higher frequencies. The other 13 carriers had SNHL of about 10 dB at 0.25 and 0.5 kHz, but less at higher frequencies. Vestibular findings were generally normal. Electrooculography demonstrated a significant lower mean light peak/dark trough ratio in Usher type I carriers compared to normal control individuals. The methods used in this study were found not to be specific enough to clinically identify carriers of Usher type I syndrome. Nevertheless it is remarkable that a number of obligate carriers showed significant audiological and ophthalmological abnormalities.

Original languageEnglish (US)
Pages (from-to)375-379
Number of pages5
JournalAmerican journal of medical genetics
Issue number3
StatePublished - 1995
Externally publishedYes


  • Usher syndrome
  • autosomal recessive disorder
  • genetic blindness
  • genetic deafness
  • obligate carrier
  • retinitis pigmentosa

ASJC Scopus subject areas

  • Genetics
  • Genetics(clinical)


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