An inherited night blindness in Wiltshire sheep

2022 ◽  
pp. 030098582110674
Author(s):  
Hayley Hunt ◽  
Keren E. Dittmer ◽  
Dorian J. Garrick ◽  
Robert A. Fairley ◽  
Stephen J. Heap ◽  
...  
Keyword(s):  
Retinal Degeneration ◽  
Night Blindness ◽  
Autosomal Recessive Inheritance ◽  
Homozygosity Mapping ◽  
Pedigree Analysis ◽  
Rod Photoreceptors ◽  
Progressive Retinal Atrophy ◽  
Inherited Retinal Dystrophies ◽  
Retinal Dystrophies ◽  
Retinal Blood Vessels

Twelve cases of adult-onset blindness were identified in a flock of 130 polled Wiltshire sheep in New Zealand over a 3-year period. Affected sheep developed night blindness between 2 and 3 years of age, which progressed to complete blindness by 4 to 5 years of age. Fundic examination findings included progressive tapetal hyperreflectivity and attenuation of retinal blood vessels. Histologically, the retinas had a selective loss of rod photoreceptors with initial preservation of cone photoreceptors. Retinal degeneration was not accompanied by any other ocular or central nervous system abnormalities, and pedigree analysis suggested an inherited basis for the disease. Mating an affected Wiltshire ram to 2 affected Wiltshire ewes resulted in 6 progeny that all developed retinal degeneration by 2 years of age, while mating of the same affected ram to 6 unaffected ewes resulted in 8 unaffected progeny, consistent with autosomal recessive inheritance. Homozygosity mapping of 5 affected Wiltshire sheep and 1 unaffected Wiltshire sheep using an OvineSNP50 Genotyping BeadChip revealed an identical-by-descent region on chromosome 5, but none of the genes within this region were considered plausible candidate genes. Whole-genome sequencing of 2 affected sheep did not reveal any significant mutations in any of the genes associated with retinitis pigmentosa in humans or progressive retinal atrophy in dogs. Inherited progressive retinal degeneration affecting rod photoreceptors has not been previously reported in sheep, but this disease has several similarities to inherited retinal dystrophies in other species.

scholarly journals Nutraceutical Supplementation Ameliorates Visual Function, Retinal Degeneration, and Redox Status in rd10 Mice

Antioxidants ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1033
Author(s):  
Lorena Olivares-González ◽  
Sheyla Velasco ◽  
Isabel Campillo ◽  
David Salom ◽  
Emilio González-García ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Retinal Degeneration ◽  
Antioxidant Properties ◽  
Photoreceptor Cells ◽  
Redox Status ◽  
Inherited Retinal Dystrophies ◽  
Stress Markers ◽  
Retinal Dystrophies ◽  
Progressive Degeneration ◽  
Light Stimuli

Background: Retinitis pigmentosa (RP) is a group of inherited retinal dystrophies characterized by progressive degeneration of photoreceptor cells. Ocular redox status is altered in RP suggesting oxidative stress could contribute to their progression. In this study, we investigated the effect of a mixture of nutraceuticals with antioxidant properties (NUT) on retinal degeneration in rd10 mice, a model of RP. Methods: NUT was orally administered to rd10 mice from postnatal day (PD) 9 to PD18. At PD18 retinal function and morphology were examined by electroretinography (ERG) and histology including TUNEL assay, immunolabeling of microglia, Müller cells, and poly ADP ribose polymers. Retinal redox status was determined by measuring the activity of antioxidant enzymes and some oxidative stress markers. Gene expression of the cytokines IL-6, TNFα, and IL-1β was assessed by real-time PCR. Results: NUT treatment delayed the loss of photoreceptors in rd10 mice partially preserving their electrical responses to light stimuli. Moreover, it ameliorated redox status and reduced inflammation including microglia activation, upregulation of cytokines, reactive gliosis, and PARP overactivation. Conclusions: NUT ameliorated retinal functionality and morphology at early stages of RP in rd10 mice. This formulation could be useful as a neuroprotective approach for patients with RP in the future.

scholarly journals Comprehensive Geno- and Phenotyping in a Complex Pedigree Including Four Different Inherited Retinal Dystrophies

Genes ◽  
2020 ◽  
Vol 11 (2) ◽  
pp. 137
Author(s):  
Johannes Birtel ◽  
Martin Gliem ◽  
Kristina Hess ◽  
Theresa H. Birtel ◽  
Frank G. Holz ◽  
...  
Keyword(s):  
Genetic Testing ◽  
Night Blindness ◽  
Molecular Genetic ◽  
Cone Dystrophy ◽  
Molecular Testing ◽  
Congenital Stationary Night Blindness ◽  
Molecular Genetic Testing ◽  
Inherited Retinal Dystrophies ◽  
Retinal Dystrophies ◽  
Novel Variant

Inherited retinal dystrophies (IRDs) are characterized by high clinical and genetic heterogeneity. A precise characterization is desirable for diagnosis and has impact on prognosis, patient counseling, and potential therapeutic options. Here, we demonstrate the effectiveness of the combination of in-depth retinal phenotyping and molecular genetic testing in complex pedigrees with different IRDs. Four affected Caucasians and two unaffected relatives were characterized including multimodal retinal imaging, functional testing, and targeted next-generation sequencing. A considerable intrafamilial phenotypic and genotypic heterogeneity was identified. While the parents of the index family presented with rod-cone dystrophy and ABCA4-related retinopathy, their two sons revealed characteristics in the spectrum of incomplete congenital stationary night blindness and ocular albinism, respectively. Molecular testing revealed previously described variants in RHO, ABCA4, and MITF as well as a novel variant in CACNA1F. Identified variants were verified by intrafamilial co-segregation, bioinformatic annotations, and in silico analysis. The coexistence of four independent IRDs caused by distinct mutations and inheritance modes in one pedigree is demonstrated. These findings highlight the complexity of IRDs and underscore the need for the combination of extensive molecular genetic testing and clinical characterization. In addition, a novel variant in the CACNA1F gene is reported associated with incomplete congenital stationary night blindness.

scholarly journals On the Wrong Track: Alterations of Ciliary Transport in Inherited Retinal Dystrophies

2021 ◽  
Vol 9 ◽  
Author(s):  
Laura Sánchez-Bellver ◽  
Vasileios Toulis ◽  
Gemma Marfany
Keyword(s):  
Retinal Degeneration ◽  
Outer Segment ◽  
Molecular Mechanisms ◽  
Photoreceptor Cells ◽  
Cellular Functions ◽  
Inherited Disorders ◽  
Inherited Retinal Dystrophies ◽  
Retinal Dystrophies ◽  
Elevated Protein ◽  
And Function

Ciliopathies are a group of heterogeneous inherited disorders associated with dysfunction of the cilium, a ubiquitous microtubule-based organelle involved in a broad range of cellular functions. Most ciliopathies are syndromic, since several organs whose cells produce a cilium, such as the retina, cochlea or kidney, are affected by mutations in ciliary-related genes. In the retina, photoreceptor cells present a highly specialized neurosensory cilium, the outer segment, stacked with membranous disks where photoreception and phototransduction occurs. The daily renewal of the more distal disks is a unique characteristic of photoreceptor outer segments, resulting in an elevated protein demand. All components necessary for outer segment formation, maintenance and function have to be transported from the photoreceptor inner segment, where synthesis occurs, to the cilium. Therefore, efficient transport of selected proteins is critical for photoreceptor ciliogenesis and function, and any alteration in either cargo delivery to the cilium or intraciliary trafficking compromises photoreceptor survival and leads to retinal degeneration. To date, mutations in more than 100 ciliary genes have been associated with retinal dystrophies, accounting for almost 25% of these inherited rare diseases. Interestingly, not all mutations in ciliary genes that cause retinal degeneration are also involved in pleiotropic pathologies in other ciliated organs. Depending on the mutation, the same gene can cause syndromic or non-syndromic retinopathies, thus emphasizing the highly refined specialization of the photoreceptor neurosensory cilia, and raising the possibility of photoreceptor-specific molecular mechanisms underlying common ciliary functions such as ciliary transport. In this review, we will focus on ciliary transport in photoreceptor cells and discuss the molecular complexity underpinning retinal ciliopathies, with a special emphasis on ciliary genes that, when mutated, cause either syndromic or non-syndromic retinal ciliopathies.

scholarly journals Whole exome sequencing and homozygosity mapping reveals genetic defects in consanguineous Iranian families with inherited retinal dystrophies

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Arash Salmaninejad ◽  
Nicola Bedoni ◽  
Zeinab Ravesh ◽  
Mathieu Quinodoz ◽  
Nasser Shoeibi ◽  
...  
Keyword(s):  
Exome Sequencing ◽  
Whole Exome Sequencing ◽  
Snp Array ◽  
Homozygosity Mapping ◽  
Retinal Cell ◽  
Additional Information ◽  
Inherited Retinal Dystrophies ◽  
Pathogenic Variants ◽  
Retinal Dystrophies ◽  
Whole Exome

Abstract Inherited retinal dystrophies (IRDs), displaying pronounced genetic and clinical heterogeneity, comprise of a broad range of diseases characterized by progressive retinal cell death and gradual loss of vision. By the combined use of whole exome sequencing (WES), SNP-array and WES-based homozygosity mapping, as well as directed DNA sequencing (Sanger), we have identified nine pathogenic variants in six genes (ABCA4, RPE65, MERTK, USH2A, SPATA7, TULP1) in 10 consanguineous Iranian families. Six of the nine identified variants were novel, including a putative founder mutation in ABCA4 (c.3260A>G, p.Glu1087Gly), detected in two families from Northeastern Iran. Our findings provide additional information to the molecular pathology of IRDs in Iran, hopefully contributing to better genetic counselling and patient management in the respective families from this country.

scholarly journals YARS2 Missense Variant in Belgian Shepherd Dogs with Cardiomyopathy and Juvenile Mortality

Genes ◽  
2020 ◽  
Vol 11 (3) ◽  
pp. 313
Author(s):  
Corinne Gurtner ◽  
Petra Hug ◽  
Miriam Kleiter ◽  
Kernt Köhler ◽  
Elisabeth Dietschi ◽  
...  
Keyword(s):  
Genetic Defect ◽  
Autosomal Recessive Inheritance ◽  
Missense Variant ◽  
Homozygosity Mapping ◽  
Pedigree Analysis ◽  
Trna Synthetase ◽  
Loss Of Function ◽  
Juvenile Mortality ◽  
Abnormal Accumulation ◽  
The Central Nervous System

Dog puppy loss by the age of six to eight weeks after normal development is relatively uncommon. Necropsy findings in two spontaneously deceased Belgian Shepherd puppies indicated an abnormal accumulation of material in several organs. A third deceased puppy exhibited mild signs of an inflammation in the central nervous system and an enteritis. The puppies were closely related, raising the suspicion of a genetic cause. Pedigree analysis suggested a monogenic autosomal recessive inheritance. Combined linkage and homozygosity mapping assigned the most likely position of a potential genetic defect to 13 genome segments totaling 82 Mb. The genome of an affected puppy was sequenced and compared to 645 control genomes. Three private protein changing variants were found in the linked and homozygous regions. Targeted genotyping in 96 Belgian Shepherd dogs excluded two of these variants. The remaining variant, YARS2:1054G>A or p.Glu352Lys, was perfectly associated with the phenotype in a cohort of 474 Belgian Shepherd dogs. YARS2 encodes the mitochondrial tyrosyl-tRNA synthetase 2 and the predicted amino acid change replaces a negatively charged and evolutionary conserved glutamate at the surface of the tRNA binding domain of YARS2 with a positively charged lysine. Human patients with loss-of-function variants in YARS2 suffer from myopathy, lactic acidosis, and sideroblastic anemia 2, a disease with clinical similarities to the phenotype of the studied dogs. The carrier frequency was 27.2% in the tested Belgian Shepherd dogs. Our data suggest YARS2:1054G>A as the candidate causative variant for the observed juvenile mortality.

scholarly journals Homozygosity mapping reveals novel and known mutations in Pakistani families with inherited retinal dystrophies

2015 ◽  
Vol 5 (1) ◽  
Author(s):  
Muhammad Arif Nadeem Saqib ◽  
Konstantinos Nikopoulos ◽  
Ehsan Ullah ◽  
Falak Sher Khan ◽  
Jamila Iqbal ◽  
...  
Keyword(s):  
Homozygosity Mapping ◽  
Inherited Retinal Dystrophies ◽  
Retinal Dystrophies ◽  
Pakistani Families

scholarly journals Development of an optimized AAV2/5 gene therapy vector for Leber congenital amaurosis owing to defects in RPE65

Gene Therapy ◽  
2016 ◽  
Vol 23 (12) ◽  
pp. 857-862 ◽  
Author(s):  
A Georgiadis ◽  
Y Duran ◽  
J Ribeiro ◽  
L Abelleira-Hervas ◽  
S J Robbie ◽  
...  
Keyword(s):  
Retinal Degeneration ◽  
Early Stage ◽  
Rod Photoreceptor ◽  
Adeno Associated Virus ◽  
Gene Therapy Vector ◽  
Leber Congenital Amaurosis ◽  
Inherited Retinal Dystrophies ◽  
Retinal Dystrophies ◽  
Serotype 5 ◽  
Subretinal Injection

Abstract Leber congenital amaurosis is a group of inherited retinal dystrophies that cause severe sight impairment in childhood; RPE65-deficiency causes impaired rod photoreceptor function from birth and progressive impairment of cone photoreceptor function associated with retinal degeneration. In animal models of RPE65 deficiency, subretinal injection of recombinant adeno-associated virus (AAV) 2/2 vectors carrying RPE65 cDNA improves rod photoreceptor function, and intervention at an early stage of disease provides sustained benefit by protecting cone photoreceptors against retinal degeneration. In affected humans, administration of these vectors has resulted to date in relatively modest improvements in photoreceptor function, even when retinal degeneration is comparatively mild, and the duration of benefit is limited by progressive retinal degeneration. We conclude that the demand for RPE65 in humans is not fully met by current vectors, and predict that a more powerful vector will provide more durable benefit. With this aim we have modified the original AAV2/2 vector to generate AAV2/5-OPTIRPE65. The new configuration consists of an AAV vector serotype 5 carrying an optimized hRPE65 promoter and a codon-optimized hRPE65 gene. In mice, AAV2/5-OPTIRPE65 is at least 300-fold more potent than our original AAV2/2 vector.

scholarly journals NRL S50T mutation and the importance of ‘founder effects’ in inherited retinal dystrophies

2000 ◽  
Vol 8 (10) ◽  
pp. 783-787 ◽  
Author(s):  
David AR Bessant ◽  
Annette M Payne ◽  
Catherine Plant ◽  
Alan C Bird ◽  
Anand Swaroop ◽  
...  
Keyword(s):  
Founder Effects ◽  
Inherited Retinal Dystrophies ◽  
Retinal Dystrophies

scholarly journals Bestrophinopathies: perspectives on clinical disease, Bestrophin-1 function and developing therapies

2021 ◽  
Vol 13 ◽  
pp. 251584142199719
Author(s):  
Simranjeet Singh Grewal ◽  
Joseph J. Smith ◽  
Amanda-Jayne F. Carr
Keyword(s):  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Induced Pluripotent Stem Cell ◽  
Underlying Disease ◽  
Incomplete Penetrance ◽  
Inherited Retinal Dystrophies ◽  
Retinal Dystrophies ◽  
High Acuity ◽  
Induced Pluripotent

Bestrophinopathies are a group of clinically distinct inherited retinal dystrophies that typically affect the macular region, an area synonymous with central high acuity vision. This spectrum of disorders is caused by mutations in bestrophin1 ( BEST1), a protein thought to act as a Ca2+-activated Cl- channel in the retinal pigment epithelium (RPE) of the eye. Although bestrophinopathies are rare, over 250 individual pathological mutations have been identified in the BEST1 gene, with many reported to have various clinical expressivity and incomplete penetrance. With no current clinical treatments available for patients with bestrophinopathies, understanding the role of BEST1 in cells and the pathological pathways underlying disease has become a priority. Induced pluripotent stem cell (iPSC) technology is helping to uncover disease mechanisms and develop treatments for RPE diseases, like bestrophinopathies. Here, we provide a comprehensive review of the pathophysiology of bestrophinopathies and highlight how patient-derived iPSC-RPE are being used to test new genomic therapies in vitro.

scholarly journals Carbon Dot Nanoparticles: Exploring the Potential Use for Gene Delivery in Ophthalmic Diseases

Nanomaterials ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 935
Author(s):  
Manas R. Biswal ◽  
Sofia Bhatia
Keyword(s):  
Gene Delivery ◽  
Therapeutic Option ◽  
Retinal Dystrophy ◽  
Retinal Cells ◽  
Adeno Associated Virus ◽  
Inherited Retinal Dystrophies ◽  
Retinal Dystrophies ◽  
Efficient Gene ◽  
New Type ◽  
Viral Nanoparticles

Ocular gene therapy offers significant potential for preventing retinal dystrophy in patients with inherited retinal dystrophies (IRD). Adeno-associated virus (AAV) based gene transfer is the most common and successful gene delivery approach to the eye. These days, many studies are using non-viral nanoparticles (NPs) as an alternative therapeutic option because of their unique properties and biocompatibility. Here, we discuss the potential of carbon dots (CDs), a new type of nanocarrier for gene delivery to the retinal cells. The unique physicochemical properties of CDs (such as optical, electronic, and catalytic) make them suitable for biosensing, imaging, drug, and gene delivery applications. Efficient gene delivery to the retinal cells using CDs depends on various factors, such as photoluminescence, quantum yield, biocompatibility, size, and shape. In this review, we focused on different approaches used to synthesize CDs, classify CDs, various pathways for the intake of gene-loaded carbon nanoparticles inside the cell, and multiple studies that worked on transferring nucleic acid in the eye using CDs.

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