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Ophthalmology
Published in Stephan Strobel, Lewis Spitz, Stephen D. Marks, Great Ormond Street Handbook of Paediatrics, 2019
Yellow lesions may be seen in Best’s vitelliform macular dystrophy, a dominantly inherited condition that starts in childhood. In the early stages there may be no lesion at the macula but usually there is an egg yolk-like lesion at the macula (Figs 7.38, 7.39).
Write short notes on the electrophysiological investigations of the visual pathway
Published in Nathaniel Knox Cartwright, Petros Carvounis, Short Answer Questions for the MRCOphth Part 1, 2018
Nathaniel Knox Cartwright, Petros Carvounis
Changes in the EOG usually parallel changes seen in the electroretinogram (ERG), a notable exception being Best’s vitelliform macular dystrophy when the EOG is abnormal but the ERG normal. The relationship of the EOG to physiological functions of the retinal pigment epithelium (RPE) is unclear as it does not correlate with pigmentary changes or visual function.
Quantitative autofluorescence: Review of Current Technical Aspects and Applications in Chorioretinal Disease
Published in Seminars in Ophthalmology, 2021
Iris Deitch, Kevin Ferenchak, John B. Miller
Best vitelliform macular dystrophy is caused by mutations in the BEST1 gene.24 BEST1 encodes the multifunctional bestrophin-1 (BEST1) protein that is located in the basolateral membrane of RPE and forms a Ca2+ activated Cl- channel. It is involved in the regulation of RPE Ca2+ channels and has a role in ocular development.25 More than 200 different human BEST1 mutations have been described to date.26 Mutations in BEST1 are associated with five distinct retinal degenerative diseases which are referred to as bestrophinopathies. The most common of these is Best vitelliform macular dystrophy (BVMD), an autosomal dominant form of macular degeneration characterized by an abnormal accumulation of lipofuscin within and beneath the RPE cells.26
Diagnosis, management and future treatment options for adult-onset foveomacular vitelliform dystrophy
Published in Expert Review of Ophthalmology, 2018
Adriano Carnevali, Wedad Al-Dolat, Riccardo Sacconi, Eleonora Corbelli, Lea Querques, Francesco Bandello, Giuseppe Querques
Best vitelliform macular dystrophy, also called Best disease, is the most common form of autosomal dominant macular dystrophy. Best vitelliform macular dystrophy is caused by mutations in BEST1 gene [38]. Compared to typical AOFVD, Best disease generally has an earlier age at onset and presents with larger vitelliform lesions. Unlike AOFVD, nearly all patients with Best disease have markedly subnormal EOGs. In the same way to AOFVD, the lesions in Best disease can be several and multifocal [39]. Moreover, the genetic subset of AOFVD can be considered a mild form of Best disease that presents with normal EOG findings [40,41].
Novel MFSD8 mutation causing non-syndromic asymmetric adult-onset macular dystrophy
Published in Ophthalmic Genetics, 2023
Aaron Z. Priluck, Mark P. Breazzano
Our patient’s phenotype is somewhat unique compared to prior reports given her relatively late age of onset, asymmetry of her visual acuity decline, and abnormal EOG. The heterozygous variants in the BEST1 (c.584C>T), RPE65 (c.11 + 5G>A), and PNPLA6 (c.3247del) genes identified in our patient have previously been found to cause autosomal recessive inherited retinal disease (14–16) and were therefore not considered to account for our patient’s phenotype. However, some of these unique variants may interact in an unknown way to contribute to our patient’s phenotype. For example, the carrier status of the BEST1 mutation may account for our patient’s reduced Arden ratios given prior reports of normal EOGs in four patients with non-syndromic macular dystrophy secondary to MFSD8 mutations (2). One series identified a heterozygous carrier of the c.974T > C variant of the BEST1 gene who was clinically normal with normal OCT and full-field ERG, but had subnormal Arden ratios, although carriers of BEST1 mutations have also been reported to have normal EOG findings (17). As such, our patient’s abnormal EOG findings may have been due to her carrier state of a BEST1 variant rather than her pathogenic MFSD8 variants. However, her BEST1 variant would not account for her other findings. The only adult-onset bestrophinopathy is BEST1 adult-onset vitelliform macular dystrophy (AVMD), which manifests with macular vitelliform lesions that become atrophic with time, dome-shaped outer retinal hyporeflective or hyperreflective material and subretinal fluid, and a normal or subnormal electrooculogram. Best vitelliform macular dystrophy generally has an abnormal electrooculogram but presents in childhood and with fundus and OCT changes similar to AVMD – see Table 2. for more comparisons (18). Moreover, each of these genes encode proteins localized to the photoreceptors (i.e., PNPLA6 (16) and retinal pigment epithelium (i.e., BEST1 (19), RPE65 (20)). Thus, being in the carrier state for variants of multiple genes involved in the normal function of photoreceptors and the retinal pigment epithelium may have potentiated her unique phenotype. Khan et al. suggested, based on a case series of patients with MFSD8 mutations, that mildly reduced gene function results in an isolated late-onset maculopathy, reduced gene function causes earlier onset and more generalized rod-cone dysfunction, and complete loss of function leads to generalized central nervous system abnormalities (6). The amount of reduction of function in the MFSD8 gene product due to her combination of unique variants is unknown but may have been sufficient to account for her phenotype though further interactions with possible reduction in function due to her carrier state of the other retinal genes may also have contributed.