Disease relevance of Night Blindness

• X-linked retinitis pigmentosa (XLRP) is characterized by retinal degeneration with night blindness and progressive reduction of the visual fields [1].
• Mutations in the gene encoding 11-cis-retinol dehydrogenase (RDH5; EC ) are associated with fundus albipunctatus, an autosomal recessive eye disease characterized by stationary night blindness and accumulation of white spots in the retina [2].
• More than 100 mutations within the rhodopsin gene have been found to be responsible for some forms of retinitis pigmentosa, a progressive retinal degeneration characterized by night blindness and subsequent disturbance of day vision that may eventually result in total blindness [3].
• Illustrative data from India and Cambodia on childhood xerophthalmia and maternal night blindness rates are used to demonstrate the validity of using a 5% prevalence of maternal night blindness as indicative of a community vitamin A deficiency problem [4].
• Usher syndrome is a heterogeneous group of autosomal recessive disorders that combines variably severe congenital neurosensory hearing impairment with progressive night-blindness and visual loss similar to that in retinitis pigmentosa [5].

Psychiatry related information on Night Blindness

• In Duchenne and Becker muscular dystrophy abnormal or deficient dystrophin expression leads to muscle degeneration and has been implicated in mental retardation and a form of night blindness [6].

High impact information on Night Blindness

• Here we have studied 22 families with 'complete' X-linked CSNB (CSNB1; MIM 310500; ref. 4) in which affected males have night blindness, some photopic vision loss and a defect of the ON-pathway [7].
• The complete form of X-linked congenital stationary night blindness is caused by mutations in a gene encoding a leucine-rich repeat protein [8].
• Our results suggest that mutant alleles in RDH5 are a cause of fundus albipunctatus, a rare form of stationary night blindness characterized by a delay in the regeneration of cone and rod photopigments [9].
• RP is characterized by night blindness and progressive degeneration of the midperipheral retina, accompanied by bone spicule-like pigmentary deposits and a reduced or absent electroretinogram (ERG) [10].
• Loss-of-function mutations in a calcium-channel alpha1-subunit gene in Xp11.23 cause incomplete X-linked congenital stationary night blindness [11].

Chemical compound and disease context of Night Blindness

• Night blindness in Sorsby's fundus dystrophy reversed by vitamin A [12].
• We show here that the mutation Gly 90-->Asp (G90D) in the second transmembrane segment of rhodopsin, which causes congenital night blindness, also constitutively activates opsin [13].
• As rod photoreceptors are responsible for night vision, we administered isotretinoin to rats to learn whether night blindness resulted from rod cell death or from rod functional impairment [14].
• Inhibition of the visual cycle in vivo by 13-cis retinoic acid protects from light damage and provides a mechanism for night blindness in isotretinoin therapy [14].
• Patients taking these drugs often show side effects resembling the symptoms of hypovitaminosis A, namely, night blindness and decreased plasma retinol levels [15].

Biological context of Night Blindness

• Our results indicate that null mutations in the rhodopsin kinase gene are a cause of Oguchi disease and extend the known genetic heterogeneity in congenital stationary night blindness [16].
• Based on these results, rod transducin joins rhodopsin and the beta subunit of rod cGMP-phosphodiesterase to become the third component of the rod phototransduction cascade where a defect is implicated as a cause of stationary night blindness [17].
• Retinitis pigmentosa (RP) is a group of disorders characterized by progressive degeneration of the outer retina, resulting in night blindness, visual field loss, an abnormal electroretinogram, and characteristic retinal pigmentary changes [18].
• X-linked congenital stationary night blindness (CSNB1) is a hereditary retinal disorder in which clinical features in affected males usually include myopia, nystagmus, and impaired visual acuity [19].
• Biochemical evidence for pathogenicity of rhodopsin kinase mutations correlated with the oguchi form of congenital stationary night blindness [20].

Anatomical context of Night Blindness

• To date, three different mutations in the RK locus have been associated with Oguchi disease, an autosomal recessive form of stationary night blindness in man characterized in part by delayed photoreceptor recovery [Yamamoto, S. , Sippel, K. C., Berson, E. L. & Dryja, T. P. (1997) Nat. Genet. 15, 175-178] [20].
• The occurrence of symptoms of night blindness in 12 patients and a family history of retinitis pigmentosa in two of these may signify a possible malfunction of the retinal pigment epithelium [21].
• More than 7.2 million pregnant women in the developing world are VA-deficient (serum or breast-milk vitamin A concentrations < 0.70 micro mol/L), and another 13.5 million have low VA status (0.70-1.05 micro mol/L); >6 million women develop night blindness (XN) during pregnancy annually [22].
• Ocular symptoms consisting of night blindness and sensations of 'shimmering lights' persisted after total resection of the inguinal lymph node metastases and administration of dacarbazine and prednisone [23].
• In addition, mu causes inner ear abnormalities and pe has symptoms associated with night blindness [24].

Gene context of Night Blindness

• Novel mutations in CACNA1F and NYX in Dutch families with X-linked congenital stationary night blindness [25].
• CONCLUSIONS: We found that ESCS, GFS, and CPRD can all have the same genetic basis.Clinical Relevance The combination of night blindness, hyperopia, and clumped retinal pigment deposits should raise the suspicion that a patient has NR2E3 disease [26].
• RP causes night blindness, a gradual loss of peripheral visual fields, and eventual loss of central vision [27].
• Overall, our cohort of LCA carriers did not describe significant subjective visual difficulties, including nyctalopia and/or photosensitivity [28].
• Electroretinograms (ERGs) in the adult Bhlhb4 knockout (Bhlhb4(-/-)) showed that the loss of Bhlhb4 resulted in disrupted rod signaling and profound retinal dysfunction resembling human congenital stationary night blindness (CSNB), characterized by the loss of the scotopic ERG b-wave [29].

Analytical, diagnostic and therapeutic context of Night Blindness

• These experiments also suggest mutations in AP-3 subunits as a basis for unique forms of human Hermansky-Pudlak syndrome and congenital night blindness, for which the pearl mouse is an appropriate animal model [30].
• Vitamin A deficiency associated with retinopathy and night blindness was observed in a patient 4 yr after jejunoileal bypass [31].
• Three unrelated boys, ages 2, 6, and 10 years, who have congenital stationary night blindness with myopia and a Schubert-Bornschein-type electroretinogram finding, were found to show a "paradoxical" pupillary constriction in darkness [32].
• CONCLUSIONS: Gastric bypass procedures can cause vitamin A deficiency leading to serious ocular complications, including xerophthalmia, nyctalopia, and ultimate blindness [33].
• PURPOSE: To report the ocular complications of xerophthalmia, nyctalopia, and visual deterioration to legal blindness as a result of inadequate vitamin A supplementation after malabsorptive bariatric surgery [33].

References