Electroretinographic findings in three family members with X-linked juvenile retinoschisis associated with a novel Pro192Thr mutation of the XLRS1 gene

Jpn J Ophthalmol. Sep-Oct 2002;46(5):568-76. doi: 10.1016/s0021-5155(02)00539-7.

Abstract

Purpose: To present ocular findings in three family members with X-linked juvenile retinoschisis (XLRS) associated with a novel Pro192Thr mutation.

Cases: We examined 21- (Case 1), 17- (Case 2), and 10-year-old (Case 3) male patients who showed wheel-like cystic lesions in the macula and a silver-gray reflex in the peripheral retina. Case 2 was a cousin of Case 1. Case 3 was a brother of Case 2.

Methods: Scotopic electroretinogram (ERG) (dim and bright flash), oscillatory potentials, photopic ERG, and 30-Hz flicker responses were recorded in each patient. The XLRS1 gene was analyzed in patient blood samples by a direct sequencing method.

Results: A novel missense mutation (Pro192Thr) was identified in the XLRS1 gene in each patient. Variable b/a ratios upon scotopic bright flash stimulation were evident (Case 1: right 1.16, left 1.20; Case 2: right 0.98, left 1.01; Case 3: right 0.81, left 0.83). Only Case 3 showed the typical "negative" waveform. The amplitude of rod b-waves was significantly decreased in all patients.

Conclusions: Three cases with a novel Pro192Thr mutation showed the phenotypic variation in ERG, especially in b/a ratio, which has been considered an important diagnostic parameter.

Publication types

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

MeSH terms

  • Adolescent
  • Adult
  • Base Sequence / genetics
  • Child
  • Chromosomes, Human, X*
  • DNA / genetics
  • Electroretinography
  • Eye Proteins / genetics*
  • Genetic Linkage*
  • Humans
  • Male
  • Mutation, Missense / physiology*
  • Pedigree
  • Photic Stimulation
  • Proline
  • Retina / physiopathology*
  • Retinal Rod Photoreceptor Cells / physiopathology
  • Retinoschisis / genetics*
  • Retinoschisis / physiopathology*
  • Threonine

Substances

  • Eye Proteins
  • RS1 protein, human
  • Threonine
  • DNA
  • Proline