Dark adaptation testing in heterozygotes of Usher's syndrome.

Sondheimer, Stuart; Fishman, Gerald A.; Young, R S; Vasquez, Victoria

doi:10.1136/bjo.63.8.547

Cited by 15 publications

(6 citation statements)

References 5 publications

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“…De Haas et al (1970) reported elevated dark adaptation thresholds in heterozygotes for Usher syndrome, and Holland et al (1972) reported gyrate atrophy of the choroid and retina in carriers. Sondheimer et al (1979) did not find fundus changes or dark adaptation abnormalities in their 14 heterozygotes. Heterozygote manifestation was not observed in the 35 obligate carriers for Usher syndrome in the present material.…”

Section: Discussionmentioning

confidence: 71%

Usher syndrome in four Norwegian counties

Grøndahl¹,

Mjôen²

1986

Clinical Genetics

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Among 89 probands selected for tapeto‐retinal degeneration, 18 (20%) were given the diagnosis of Usher syndrome. Among the relatives of the probands another 10 cases of Usher syndrome were found. The distribution on type diagnoses was: Usher syndrome type I: 14 cases, type II: 10 cases and type III: four cases. The pattern of inheritance was autosomal recessive for 12 families, and the remaining six probands were solitary cases without consanguinity between the parents. There was a high intrafamiliar correlation with respect to hearing function, indicating genetic heterogeneity in Usher syndrome. Obligate heterozygotes did not demonstrate heterozygote manifestation. One man with Usher syndrome type I was psychotic, the remaining 27 did not demonstrate serious psychic disturbances. Atactic gait was not observed, though vestibular response was abolished in three patients with Usher syndrome type I. Three patients with type II and one person with type III had normal vestibular response. The prognosis for visual function was not highly correlated to the type diagnosis or to the age when hemeralopia was first noticed. Visual function was good before 30 years of age and bad in most patients after the age of 50.

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Section: Discussionmentioning

confidence: 71%

Usher syndrome in four Norwegian counties

Grøndahl¹,

Mjôen²

1986

Clinical Genetics

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“…No abnormalities in the dark adaptation kinetics have been recently found in USH1B patients [20]. However, delayed recovery of rod sensitivity after light desensitization has been reported in carrier and affected USH patients [51], [52] as well as in individuals with retinitis pigmentosa [53], [54], [55]. In any case the recovery from light desensitization represents an important functional read-out to test the efficacy of experimental therapies for the USH1B retina at the pre-clinical level.…”

Section: Discussionmentioning

confidence: 99%

Myosin7a Deficiency Results in Reduced Retinal Activity Which Is Improved by Gene Therapy

et al. 2013

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Mutations in MYO7A cause autosomal recessive Usher syndrome type IB (USH1B), one of the most frequent conditions that combine severe congenital hearing impairment and retinitis pigmentosa. A promising therapeutic strategy for retinitis pigmentosa is gene therapy, however its pre-clinical development is limited by the mild retinal phenotype of the shaker1 (sh1−/−) murine model of USH1B which lacks both retinal functional abnormalities and degeneration. Here we report a significant, early-onset delay of sh1−/− photoreceptor ability to recover from light desensitization as well as a progressive reduction of both b-wave electroretinogram amplitude and light sensitivity, in the absence of significant loss of photoreceptors up to 12 months of age. We additionally show that subretinal delivery to the sh1−/− retina of AAV vectors encoding the large MYO7A protein results in significant improvement of sh1−/− photoreceptor and retinal pigment epithelium ultrastructural anomalies which is associated with improvement of recovery from light desensitization. These findings provide new tools to evaluate the efficacy of experimental therapies for USH1B. In addition, although AAV vectors expressing large genes might have limited clinical applications due to their genome heterogeneity, our data show that AAV-mediated MYO7A gene transfer to the sh1−/− retina is effective.

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“…Dark adaptation studies (Sondheimer et al, 1979) were performed using a Goldmann Weekers dark adaptometer and two 2° targets, one blue, the other red, presented at 15° above fixation which gave an indication of the relative contributions of the rod and cone photoreceptors to dark adaptation.…”

Section: Family Studymentioning

confidence: 99%