Usher syndrome type 1: Early detection of electroretinographic changes

Flores-Guevara, R; Renault, Francis; Loundon, Natalie; Marlin, Sandrine; Pelosse, B; Momtchilova, M.; Auzoux-Chève, M; Vermersch, Anne Isabelle; Richard, P

doi:10.1016/j.ejpn.2008.10.002

Cited by 17 publications

(18 citation statements)

References 7 publications

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“…A retrospective ERG analysis of USH1 patients as young as 17 months revealed abnormal waveforms prior to clinically detectable retinitis pigmentosa (Flores-Guevara et al, 2009), although other studies of USH1 patients in which photoreceptor loss was already clinically evident revealed no synaptic dysfunction in the remaining viable photoreceptors (Jacobson et al, 2008; Williams et al, 2009). Notably, the Ush1c216AA knock-in mouse (Lentz et al, 2010) exhibits an attenuated ERG as early as 1 month of age, prior to any histologically appreciable cell loss.…”

Section: Discussionmentioning

confidence: 96%

Harmonin (Ush1c) is required in zebrafish Müller glial cells for photoreceptor synaptic development and function

Phillips

Blanco-Sánchez

Lentz

et al. 2011

Disease Models &Amp; Mechanisms

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SUMMARYUsher syndrome is the most prevalent cause of hereditary deaf-blindness, characterized by congenital sensorineural hearing impairment and progressive photoreceptor degeneration beginning in childhood or adolescence. Diagnosis and management of this disease are complex, and the molecular changes underlying sensory cell impairment remain poorly understood. Here we characterize two zebrafish models for a severe form of Usher syndrome, Usher syndrome type 1C (USH1C): one model is a mutant with a newly identified ush1c nonsense mutation, and the other is a morpholino knockdown of ush1c. Both have defects in hearing, balance and visual function from the first week of life. Histological analyses reveal specific defects in sensory cell structure that are consistent with these behavioral phenotypes and could implicate Müller glia in the retinal pathology of Usher syndrome. This study shows that visual defects associated with loss of ush1c function in zebrafish can be detected from the onset of vision, and thus could be applicable to early diagnosis for USH1C patients.

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Section: Discussionmentioning

confidence: 96%

Harmonin (Ush1c) is required in zebrafish Müller glial cells for photoreceptor synaptic development and function

Phillips

Blanco-Sánchez

Lentz

et al. 2011

Disease Models &Amp; Mechanisms

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“…Further, the standardized ERG techniques established by the ISCEV cannot be easily carried out with children because the protocols require long gaze fixation and attention spans [41]. Thus, by utilizing a light of moderate intensity, the mesopic ERGs should be well tolerated by children [42] and avoid any potential damages to photoreceptors from light adaptation [40]. …”

Section: Discussionmentioning

confidence: 99%

Isolated mesopic rod and cone electroretinograms realized with a four-primary method

2011

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The purpose of this study was to evaluate the feasibility of measuring rod and cone electroretinograms (ERGs) at a single mesopic adaptation level. To accomplish this, a four-primary photostimulator was implemented using a commercially available ERG system (Diagnosys ColorDome) to generate three types of stimuli that temporally modulated rods alone, cones alone, and rods and cones simultaneously. For each stimulus type, ERGs were recorded as a function of temporal frequency (2, 4, 8, or 16 Hz) and mesopic light levels (0.02, 0.16, or 1.26 cd/m2) in normal observers and patients with retinitis pigmentosa (RP) or cone–rod degeneration. The normal observers ERG waveforms showed a clear periodic pattern, mirroring the sinusoidal stimuli. At all light levels, rod responses were always higher than cone responses for temporal frequencies between 2 and 8 Hz, suggesting that rods dominated the responses. Cone responses were minimal at the lowest light level and increased with increases in light level. The amplitude of the response to the combined stimuli was intermediate between that of the isolated cone and the isolated rod stimuli for all light levels. Good receptoral isolation was confirmed by the results showing (1) minimal or no rod ERGs but recordable cone ERGs in the patients and (2) high correlation between the ERG amplitudes obtained from the four-primary method and those from the ISCEV standard clinical protocol in normal observers.

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“…35, 36 Usher type 1 has previously been described phenotypically to have more severe retinal degeneration than Usher types 2 and 3. 34,37 In this study, one patient (1:4) genotyped as Usher 1D (cadherin 23, 7823G>A) illustrated a variability of the phenotype with remaining central visual function at the age of 35, verified by mf ERG.…”

Section: Discussionmentioning

confidence: 63%