Electro-oculography in Vitelliform Degeneration of the Macula

François, J.; Rouck, A. De; D, Fernandez-Sasso

doi:10.1001/archopht.1967.00980020728003

Cited by 69 publications

(27 citation statements)

References 8 publications

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“…retina, brain, and spinal cord, and RT-PCR has indicated that bestrophin also existed in kidney. Bestrophin localizes to the basolateral plasma membrane of the retinal pigment epithelium (RPE) (34) and contributes to the slow light peak of the electrooculogram (8). The function of bestrophins has been enigmatic until recently, Sun et al (46) ] (Qu Z, unpublished observations).…”

Section: Molecular Identification Of Potential Genes For Clca Currentmentioning

confidence: 99%

Characterization of Ca²⁺-activated Cl^– currents in mouse kidney inner medullary collecting duct cells

Wei

Hartzell

2003

American Journal of Physiology-Renal Physiology

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Ca2+-activated Cl– (ClCa) channels were characterized biophysically and pharmacologically in a mouse kidney inner medullary collecting duct cell line, IMCD-K2. Whole cell recording was performed with symmetrical N-methyl-d-glucamine chloride (NMDG)-Cl in the intracellular and extracellular solutions, and the intracellular Ca2+ concentration ([Ca2+]i) was adjusted with Ca2+-EGTA buffers. The amplitude of the current was dependent on [Ca2+]i. [Ca2+]i <800 nM strongly activated outwardly rectifying Cl– currents, whereas high Ca2+ (21 μM) elicited time-independent currents that did not rectify. The currents activated at low [Ca2+] exhibited time-dependent activation and deactivation. The affinity of the channel for Ca2+ was voltage dependent. The EC50 for Ca2+ was ∼0.4 μM at +100 mV and ∼1.0 μM at –100 mV. The Cl– channel blocker niflumic acid in the bath equally inhibited both inward and outward currents reversibly, with a Ki = 7.6 μM. DIDS, diphenylamine-2-carboxylic acid, and anthracene-9-carboxylic acid reversibly inhibited outward currents in a voltage-dependent manner. DTT slowly inhibited the currents, but tamoxifen did not. Comparing the biophysical and pharmacological properties, we conclude that IMCD-K2 cells express the same type of ClCa channels as those we have described in detail in Xenopus laevis oocytes (Qu Z and Hartzell HC. J Biol Chem 276: 18423–18429, 2001).

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Section: Molecular Identification Of Potential Genes For Clca Currentmentioning

confidence: 99%

Characterization of Ca²⁺-activated Cl^– currents in mouse kidney inner medullary collecting duct cells

Wei

Hartzell

2003

American Journal of Physiology-Renal Physiology

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“…Bestrophin is homologous to at least 3 other proteins coded within the human genome, 4 in the Drosophila genome, and 24 in the Caenorhabditis elegans genome, but no function has yet been ascribed to any members of this family, and they show no detectable homology to any protein of known function. In considering the possible function(s) of bestrophin, three observations suggested to us that it may be an oligomeric Cl channel: (i) VMD is associated with a reduction in the slow light peak of the electrooculogram (7,8), a component thought to reflect an increase in Cl conductance across the basolateral membrane of the RPE (9, 10); (ii) the amino acid sequence of bestrophin suggests a multispan transmembrane protein; and (iii) among the 48 disease-associated bestrophin mutations reported to date, all are dominant and almost all are missense mutations that cluster in or near the predicted transmembrane domains (5,6,(11)(12)(13)(14). Recently, Marmorstein et al (15) reported that bestrophin is localized to the basolateral membrane of the RPE, strengthening our speculation that bestrophin may be involved in the conductance relevant to the aberrant electrooculogram.…”

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confidence: 99%

The vitelliform macular dystrophy protein defines a new family of chloride channels

Sun

Tsuruo

Yau³

et al. 2002

Proc. Natl. Acad. Sci. U.S.A.

419

427

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Vitelliform macular dystrophy (VMD͞Best disease; MIM*153700) is an early-onset autosomal dominant disorder in which accumulation of lipofuscin-like material within and beneath the retinal pigment epithelium is associated with a progressive loss of central vision. Bestrophin, the protein product of the VMD gene, has four predicted transmembrane domains. There are multiple bestrophin homologues in the human, Drosophila, and Caenorhabditis elegans genomes, but no function has previously been ascribed to these proteins, and they show no detectable homology to other proteins of known function. Using heterologous expression, we show here that human, Drosophila, and C. elegans bestrophins form oligomeric chloride channels, and that human bestrophin is sensitive to intracellular calcium. Each of 15 missense mutations asscociated with VMD greatly reduces or abolishes the membrane current. Four of these mutant bestrophins were coexpressed with the wild type and each dominantly inhibited the wild-type membrane current, consistent with the dominant nature of the disease. These experiments establish the existence of a new chloride channel family and VMD as a channelopathy.

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“…Mutations in BEST1 gene disturb the function of bestrophin and ion transport by the RPE, resulting in the accumulation of fluid between the RPE and the photoreceptors [10]. Usually Best disease starts at the age of 3-15 years, with mean age 6 years [11]. The visual acuity usually remains sufficient for many years, leaving the disease not detected until much later stages.…”

Section: Discussionmentioning

confidence: 99%

Best vitelliform macular dystrophy: clinical case report

Ašmonienė¹,

Klobus²,

Liutkevičienė³

et al. 2017

Eye Care Vis

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We report a case of Best vitelliform macular dystrophy (BVD) in an 8-year-old boy complaining of reduced visual acuity in both eyes for several months. His bestcorrected visual acuity in the right eye was 0.6 and 0.3 in the left eye. Ophthalmoscopy of the right eye revealed a big yellow macular lesion surrounded by few smaller lesions with clear content and moderate edema in the central part of the retina (similar to BVD "scrambled egg" stage). In his left eye, we found a big round lesion with clear liquid boundary in the central part of the retina (similar to BVD pseudohypopyon stage). In the electro-oculogram Arden index of the right eye was 0.78 and 0.7 of the left eye (normal more than 1.8 (if <1.8; typical to BVD). We found a heterozygous mutation in exon 7 of the BEST1 gene (c.728A>T p.D243V), and conclude that the patient is very likely to suffer from BVD due to a mutation in the BEST1 gene. There were no detected mutations of the BEST1 gene in patient's both parents. We only observe this patient every 6 months because there is no causal treatment for this disorder yet.

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Electro-oculography in Vitelliform Degeneration of the Macula

Cited by 69 publications

References 8 publications

Characterization of Ca²⁺-activated Cl^– currents in mouse kidney inner medullary collecting duct cells

Characterization of Ca²⁺-activated Cl^– currents in mouse kidney inner medullary collecting duct cells

The vitelliform macular dystrophy protein defines a new family of chloride channels

Best vitelliform macular dystrophy: clinical case report

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Electro-oculography in Vitelliform Degeneration of the Macula

Cited by 69 publications

References 8 publications

Characterization of Ca2+-activated Cl– currents in mouse kidney inner medullary collecting duct cells

Characterization of Ca2+-activated Cl– currents in mouse kidney inner medullary collecting duct cells

The vitelliform macular dystrophy protein defines a new family of chloride channels

Best vitelliform macular dystrophy: clinical case report

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Characterization of Ca²⁺-activated Cl^– currents in mouse kidney inner medullary collecting duct cells

Characterization of Ca²⁺-activated Cl^– currents in mouse kidney inner medullary collecting duct cells