Analysis of photoreceptor function and inner retinal activity in juvenile X-linked retinoschisis

Vision Res. 2001 Dec;41(28):3931-42. doi: 10.1016/s0042-6989(01)00188-2.

Abstract

Thirteen retinoschisis males with genotyped XLRS1 gene mutations were examined by electroretinogram (ERG) techniques to determine photoreceptor involvement and ON-pathway and OFF-pathway sites of dysfunction. Parameters R(max) and logS determined by fitting the mathematical model of the activation phase of phototransduction to the scotopic and photopic a-wave responses, were not significantly different from normal. However, the XLRS photopic a-wave amplitudes were significantly lower than normal across all intensities, consistent with defective signaling in the OFF pathway. Long flash (150 ms) ON-OFF photopic responses showed reduced b-wave amplitude but normal d-wave amplitude, giving a reduced b/d ratio of <1.32 Hz photopic flicker ERG fundamental frequency responses showed reduced amplitude and delayed phase, consistent with abnormal signaling by both the ON- and OFF-pathway components. These results indicate that the XLRS1 protein appears not to affect photoreceptor function directly for most XLRS males, and that ERG signaling abnormalities occur in both the ON- and OFF-pathway components that originate in the proximal retina.

Publication types

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

MeSH terms

  • Adolescent
  • Adult
  • Analysis of Variance
  • Case-Control Studies
  • Child
  • Color Perception / physiology
  • Electroretinography / methods
  • Genetic Linkage
  • Genotype
  • Humans
  • Male
  • Middle Aged
  • Models, Neurological
  • Mutation / genetics
  • Photoreceptor Cells, Vertebrate / physiology*
  • Psychophysics
  • Retinal Degeneration / genetics
  • Retinal Degeneration / physiopathology*
  • Vision, Ocular / physiology
  • X Chromosome