Publications by authors named "Anthony T Moore"

292 Publications

100,000 Genomes Pilot on Rare-Disease Diagnosis in Health Care - Preliminary Report.

N Engl J Med 2021 11;385(20):1868-1880

From Genomics England (D.S., K.R.S., A.M., E.A.T., E.M.M., A.T., G.C., K.I., L.M., M. Wielscher, A.N., M. Bale, E.B., C.B., H.B., M. Bleda, A. Devereau, D.H., E. Haraldsdottir, Z.H., D.K., C. Patch, D.P., A.M., R. Sultana, M.R., A.L.T.T., C. Tregidgo, C. Turnbull, M. Welland, S. Wood, C.S., E.W., S.L., R.E.F., L.C.D., O.N., I.U.S.L., C.F.W., J.C., R.H.S., T.F., A.R., M.C.), the William Harvey Research Institute, Queen Mary University of London (D.S., K.R.S., V.C., A.T., L.M., M.R.B., D.K., S. Wood, P.C., J.O.J., T.F., M.C.), University College London (UCL) Institute of Ophthalmology (V.C., G.A., M.M., A.T.M., S. Malka, N.P., P.Y.-W.-M., A.R.W.), UCL Genetics Institute (V.C., N.W.W.), GOSgene (H.J.W.), Genetics and Genomic Medicine Programme (L.V., M.R., M.D., L.C., P. Beales, M.B.-G.), National Institute for Health Research (NIHR) Great Ormond Street Hospital Biomedical Research Centre (BRC) (M.R., S. Grunewald, S.C.-L., F.M., C. Pilkington, L.R.W., L.C., P. Beales, M.B.-G.), Infection, Immunity, and Inflammation Research and Teaching Department (P.A., L.R.W.), Stem Cells and Regenerative Medicine (N.T.), and Mitochondrial Research Group (S. Rahman), UCL Great Ormond Street Institute of Child Health, UCL Ear Institute (L.V.), the Department of Renal Medicine (D. Bockenhauer), and Institute of Cardiovascular Science (P.E.), UCL, Moorfields Eye Hospital National Health Service (NHS) Foundation Trust (V.C., G.A., M.M., A.T.M., S. Malka, N.P., A.R.W.), the National Hospital for Neurology and Neurosurgery (J.V., E.O., J.Y., K. Newland, H.R.M., J.P., N.W.W., H.H.), the Metabolic Unit (L.A., S. Grunewald, S. Rahman), London Centre for Paediatric Endocrinology and Diabetes (M.D.), and the Department of Gastroenterology (N.T.), Great Ormond Street Hospital for Children NHS Foundation Trust (L.V., D. Bockenhauer, A. Broomfield, M.A.C., T. Lam, E.F., V.G., S.C.-L., F.M., C. Pilkington, R. Quinlivan, C.W., L.R.W., A. Worth, L.C., P. Beales, M.B.-G., R.H.S.), the Clinical Genetics Department (M.R., T.B., C. Compton, C.D., E. Haque, L.I., D.J., S. Mohammed, L.R., S. Rose, D.R., G.S., A.C.S., F.F., M.I.) and St. John's Institute of Dermatology (H.F., R. Sarkany), Guy's and St. Thomas' NHS Foundation Trust, the Division of Genetics and Epidemiology, Institute of Cancer Research (C. Turnbull), Florence Nightingale Faculty of Nursing, Midwifery, and Palliative Care (T.B.), Division of Genetics and Molecular Medicine (M.A.S.), and Division of Medical and Molecular Genetics (M.I.), King's College London, NIHR BRC at Moorfields Eye Hospital (P.Y.-W.-M.), NHS England and NHS Improvement, Skipton House (V.D., A. Douglas, S. Hill), and Imperial College Healthcare NHS Trust, Hammersmith Hospital (K. Naresh), London, Open Targets and European Molecular Biology Laboratory-European Bioinformatics Institute, Wellcome Genome Campus, Hinxton (E.M.M.), the Division of Evolution and Genomic Sciences, Faculty of Biology, Medicine, and Health, University of Manchester (J.M.E., S.B., J.C.-S., S.D., G.H., H.B.T., R.T.O., G. Black, W.N.), and the Manchester Centre for Genomic Medicine, St. Mary's Hospital, Manchester University NHS Foundation Trust (J.M.E., Z.H., S.B., J.C.-S., S.D., G.H., G. Black, W.N.), Manchester, the Department of Genetic and Genomic Medicine, Institute of Medical Genetics, Cardiff University, Cardiff (H.J.W.), the Department of Clinical Neurosciences (T.R., W.W., R.H., P.F.C.), the Medical Research Council (MRC) Mitochondrial Biology Unit (T.R., W.W., P.Y.-W.-M., P.F.C.), the Department of Paediatrics (T.R.), the Department of Haematology (K.S., C. Penkett, S. Gräf, R.M., W.H.O., A.R.), the School of Clinical Medicine (K.R., E.L., R.A.F., K.P., F.L.R.), the Department of Medicine (S. Gräf), and Cambridge Centre for Brain Repair, Department of Clinical Neurosciences (P.Y.-W.-M.), University of Cambridge, NIHR BioResource, Cambridge University Hospitals (K.S., S.A., R.J., C. Penkett, E.D., S. Gräf, R.M., M.K., J.R.B., P.F.C., W.H.O., F.L.R.), and Addenbrooke's Hospital, Cambridge University Hospitals NHS Foundation Trust (G.F., P.T., O.S.-B., S. Halsall, K.P., A. Wagner, S.G.M., N.B., M.K.), Cambridge Biomedical Campus, Wellcome-MRC Institute of Metabolic Science and NIHR Cambridge BRC (M.G.), Congenica (A.H., H.S.), Illumina Cambridge (A. Wolejko, B.H., G. Burns, S. Hunter, R.J.G., S.J.H., D. Bentley), NHS Blood and Transplant (W.H.O.), and Wellcome Sanger Institute (W.H.O.), Cambridge, the Health Economics Research Centre (J. Buchanan, S. Wordsworth) and the Wellcome Centre for Human Genetics (C. Camps, J.C.T.), University of Oxford, NIHR Oxford BRC (J. Buchanan, S. Wordsworth, J.D., C. Crichton, J.W., K.W., C. Camps, S.P., N.B.A.R., A.S., J.T., J.C.T.), the Oxford Centre for Genomic Medicine (A. de Burca, A.H.N.), and the Departments of Haematology (N.B.A.R.) and Neurology (A.S.), Oxford University Hospitals NHS Foundation Trust, Oxford Genetics Laboratories, Oxford University Hospitals NHS Foundation Trust, Churchill Hospital (C. Campbell, K.G., T. Lester, J.T.), the MRC Weatherall Institute of Molecular Medicine (N.K., N.B.A.R., A.O.M.W.) and the Oxford Epilepsy Research Group (A.S.), Nuffield Department of Clinical Neurosciences (A.H.N.), University of Oxford, and the Department of Clinical Immunology (S.P.), John Radcliffe Hospital, Oxford, Peninsula Clinical Genetics Service, Royal Devon and Exeter NHS Foundation Trust (E.B.), and the University of Exeter Medical School (E.B., C.F.W.), Royal Devon and Exeter Hospital (S.E.), Exeter, Newcastle Eye Centre, Royal Victoria Infirmary (A.C.B.), the Institute of Genetic Medicine, Newcastle University, International Centre for Life (V.S., P. Brennan), Wellcome Centre for Mitochondrial Research, Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University (G.S.G., R.H., A.M.S., D.M.T., R. Quinton, R.M., R.W.T., J.A.S.), Highly Specialised Mitochondrial Service (G.S.G., A.M.S., D.M.T., R.M., R.W.T.) and Northern Genetics Service (J. Burn), Newcastle upon Tyne Hospitals NHS Foundation Trust (J.A.S.), and NIHR Newcastle BRC (G.S.G., D.M.T., J.A.S.), Newcastle upon Tyne, the Institute of Cancer and Genomic Sciences, Institute of Biomedical Research, University of Birmingham (C. Palles), and Birmingham Women's Hospital (D.M.), Birmingham, the Genomic Informatics Group (E.G.S.), University Hospital Southampton (I.K.T.), and the University of Southampton (I.K.T.), Southampton, Liverpool Women's NHS Foundation Trust, Liverpool (A. Douglas), the School of Cellular and Molecular Medicine, University of Bristol, Bristol (A.D.M.), and Yorkshire and Humber, Sheffield Children's Hospital, Sheffield (G.W.) - all in the United Kingdom; Fabric Genomics, Oakland (M. Babcock, M.G.R.), and the Ophthalmology Department, University of California, San Francisco School of Medicine, San Francisco (A.T.M.) - both in California; the Jackson Laboratory for Genomic Medicine, Farmington, CT (P.N.R.); and the Center for Genome Research and Biocomputing, Environmental and Molecular Toxicology, Oregon State University, Corvallis (M.H.).

Background: The U.K. 100,000 Genomes Project is in the process of investigating the role of genome sequencing in patients with undiagnosed rare diseases after usual care and the alignment of this research with health care implementation in the U.K. National Health Service. Other parts of this project focus on patients with cancer and infection.

Methods: We conducted a pilot study involving 4660 participants from 2183 families, among whom 161 disorders covering a broad spectrum of rare diseases were present. We collected data on clinical features with the use of Human Phenotype Ontology terms, undertook genome sequencing, applied automated variant prioritization on the basis of applied virtual gene panels and phenotypes, and identified novel pathogenic variants through research analysis.

Results: Diagnostic yields varied among family structures and were highest in family trios (both parents and a proband) and families with larger pedigrees. Diagnostic yields were much higher for disorders likely to have a monogenic cause (35%) than for disorders likely to have a complex cause (11%). Diagnostic yields for intellectual disability, hearing disorders, and vision disorders ranged from 40 to 55%. We made genetic diagnoses in 25% of the probands. A total of 14% of the diagnoses were made by means of the combination of research and automated approaches, which was critical for cases in which we found etiologic noncoding, structural, and mitochondrial genome variants and coding variants poorly covered by exome sequencing. Cohortwide burden testing across 57,000 genomes enabled the discovery of three new disease genes and 19 new associations. Of the genetic diagnoses that we made, 25% had immediate ramifications for clinical decision making for the patients or their relatives.

Conclusions: Our pilot study of genome sequencing in a national health care system showed an increase in diagnostic yield across a range of rare diseases. (Funded by the National Institute for Health Research and others.).
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http://dx.doi.org/10.1056/NEJMoa2035790DOI Listing
November 2021

Allele-specific gene editing to rescue dominant CRX-associated LCA7 phenotypes in a retinal organoid model.

Stem Cell Reports 2021 Nov 14;16(11):2690-2702. Epub 2021 Oct 14.

Department of Ophthalmology, University of California San Francisco, San Francisco, CA, USA; The Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California San Francisco, San Francisco, CA, USA. Electronic address:

Cases of Leber congenital amaurosis caused by mutations in CRX (LCA7) exhibit an early form of the disease and show signs of significant photoreceptor dysfunction and eventual loss. To establish a translational in vitro model system to study gene-editing-based therapies, we generated LCA7 retinal organoids harboring a dominant disease-causing mutation in CRX. Our LCA7 retinal organoids develop signs of immature and dysfunctional photoreceptor cells, providing us with a reliable in vitro model to recapitulate LCA7. Furthermore, we performed a proof-of-concept study in which we utilize allele-specific CRISPR/Cas9-based gene editing to knock out mutant CRX and saw moderate rescue of photoreceptor phenotypes in our organoids. This work provides early evidence for an effective approach to treat LCA7, which can be applied more broadly to other dominant genetic diseases.
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http://dx.doi.org/10.1016/j.stemcr.2021.09.007DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8580887PMC
November 2021

Variants in PAX6, PITX3 and HSF4 causing autosomal dominant congenital cataracts.

Eye (Lond) 2021 Aug 3. Epub 2021 Aug 3.

UCL Institute of Ophthalmology, University College London, London, UK.

Background: Lens development is orchestrated by transcription factors. Disease-causing variants in transcription factors and their developmental target genes are associated with congenital cataracts and other eye anomalies.

Methods: Using whole exome sequencing, we identified disease-causing variants in two large British families and one isolated case with autosomal dominant congenital cataract. Bioinformatics analysis confirmed these disease-causing mutations as rare or novel variants, with a moderate to damaging pathogenicity score, with testing for segregation within the families using direct Sanger sequencing.

Results: Family A had a missense variant (c.184 G>A; p.V62M) in PAX6 and affected individuals presented with nuclear cataract. Family B had a frameshift variant (c.470-477dup; p.A160R*) in PITX3 that was also associated with nuclear cataract. A recurrent missense variant in HSF4 (c.341 T>C; p.L114P) was associated with congenital cataract in a single isolated case.

Conclusions: We have therefore identified novel variants in PAX6 and PITX3 that cause autosomal dominant congenital cataract.
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http://dx.doi.org/10.1038/s41433-021-01711-xDOI Listing
August 2021

Beyond factor H: The impact of genetic-risk variants for age-related macular degeneration on circulating factor-H-like 1 and factor-H-related protein concentrations.

Am J Hum Genet 2021 08 13;108(8):1385-1400. Epub 2021 Jul 13.

Stoller Biomarker Discovery Centre and Division of Cancer Sciences, School of Medical Sciences, Faculty of Biology, Medicine, and Health, The University of Manchester, Manchester, M13 9NQ, United Kingdom. Electronic address:

Age-related macular degeneration (AMD) is a leading cause of vision loss; there is strong genetic susceptibility at the complement factor H (CFH) locus. This locus encodes a series of complement regulators: factor H (FH), a splice variant factor-H-like 1 (FHL-1), and five factor-H-related proteins (FHR-1 to FHR-5), all involved in the regulation of complement factor C3b turnover. Little is known about how AMD-associated variants at this locus might influence FHL-1 and FHR protein concentrations. We have used a bespoke targeted mass-spectrometry assay to measure the circulating concentrations of all seven complement regulators and demonstrated elevated concentrations in 352 advanced AMD-affected individuals for all FHR proteins (FHR-1, p = 2.4 × 10; FHR-2, p = 6.0 × 10; FHR-3, p = 1.5 × 10; FHR-4, p = 1.3 × 10; FHR-5, p = 1.9 × 10) and FHL-1 (p = 4.9 × 10) when these individuals were compared to 252 controls, whereas no difference was seen for FH (p = 0.94). Genome-wide association analyses in controls revealed genome-wide-significant signals at the CFH locus for all five FHR proteins, and univariate Mendelian-randomization analyses strongly supported the association of FHR-1, FHR-2, FHR-4, and FHR-5 with AMD susceptibility. These findings provide a strong biochemical explanation for how genetically driven alterations in circulating FHR proteins could be major drivers of AMD and highlight the need for research into FHR protein modulation as a viable therapeutic avenue for AMD.
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http://dx.doi.org/10.1016/j.ajhg.2021.05.015DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8387294PMC
August 2021

Transcription factor overexpression drives reliable differentiation of retinal pigment epithelium from human induced pluripotent stem cells.

Stem Cell Res 2021 05 27;53:102368. Epub 2021 Apr 27.

Gladstone Institutes, 1650 Owens Street, San Francisco, CA 94158, USA; UCSF Department of Ophthalmology, 10 Koret Way, San Francisco, CA 94143-0730, USA; Innovative Genomics Institute, 2151 Berkeley Way, Berkeley, CA 94720, USA; UCSF Department of Medicine, 535 Mission Bay Blvd South, San Francisco, CA 94158, USA. Electronic address:

Age-related macular degeneration and genetic forms of blindness such as Best Disease and Retinitis Pigmentosa can be caused by degeneration of the Retinal Pigment Epithelium (RPE). RPE generated from patient-derived induced pluripotent stem cells (iPSCs) is valuable for both the study of disease mechanisms and development of therapeutic strategies. However, protocols to produce iPSC-derived RPE in vitro are often inefficient, labor-intensive, low-throughput, and highly variable between cell lines and within batches. Here, we report a robust, scalable method to generate iPSC-RPE using doxycycline-inducible expression of eye field transcription factors OTX2, PAX6 and MITF paired with RPE-permissive culture media. Doxycycline addition induces exogenous expression of these transcription factors in Best Disease patient- and wildtype iPSCs to efficiently produce monolayers of RPE with characteristic morphology and gene expression. Further, these RPE monolayers display functionality features including light absorption via pigmentation, polarity-driven fluid transport, and phagocytosis. With this method, we achieve a highly efficient and easily scalable differentiation without the need for mechanical isolation or enrichment methods, generating RPE cultures applicable for in vitro studies.
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http://dx.doi.org/10.1016/j.scr.2021.102368DOI Listing
May 2021

Expanding the FDXR-Associated Disease Phenotype: Retinal Dystrophy Is a Recurrent Ocular Feature.

Invest Ophthalmol Vis Sci 2021 05;62(6)

Moorfields Eye Hospital NHS Foundation Trust, London, United Kingdom.

Purpose: The purpose of this study was to report retinal dystrophy as a novel clinical feature and expand the ocular phenotype in patients harboring biallelic candidate FDXR variants.

Methods: Patients carrying biallelic candidate FDXR variants were identified by whole genome sequencing (WGS) as part of the National Institute for Health Research BioResource rare-disease and the UK's 100,000 Genomes Project (100KGP) with an additional case identified by exome sequencing. Retrospective clinical data were collected from the medical records. Haplotype reconstruction was performed in families harboring the same missense variant.

Results: Ten individuals from 8 unrelated families with biallelic candidate variants in FDXR were identified. In addition to bilateral optic atrophy and variable extra-ocular findings, 7 of 10 individuals manifested retinal dystrophy comprising dysfunction and degeneration of both rod and cone photoreceptors. Five of 10 subjects had sensorineural hearing loss. The previously unreported missense variant (c.1115C > A, p.(Pro372His)) was found in 5 of 8 (62.5%) study families. Haplotype reconstruction using WGS data demonstrated a likely ancestral haplotype.

Conclusions: FDXR-associated disease is a phenotypically heterogeneous disorder with retinal dystrophy being a major clinical feature observed in this cohort. In addition, we hypothesize that a number of factors are likely to drive the pathogenesis of optic atrophy, retinal degeneration, and perhaps the associated systemic manifestations.
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http://dx.doi.org/10.1167/iovs.62.6.2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8107637PMC
May 2021

Association of ambient air pollution with age-related macular degeneration and retinal thickness in UK Biobank.

Br J Ophthalmol 2021 Jan 25. Epub 2021 Jan 25.

UCL Institute of Ophthalmology, National Institute for Health Research Biomedical Research Centre at Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, London, Greater London, UK.

Aim: To examine the associations of air pollution with both self-reported age-related macular degeneration (AMD), and in vivo measures of retinal sublayer thicknesses.

Methods: We included 115 954 UK Biobank participants aged 40-69 years old in this cross-sectional study. Ambient air pollution measures included particulate matter, nitrogen dioxide (NO) and nitrogen oxides (NO). Participants with self-reported ocular conditions, high refractive error (< -6 or > +6 diopters) and poor spectral-domain optical coherence tomography (SD-OCT) image were excluded. Self-reported AMD was used to identify overt disease. SD-OCT imaging derived photoreceptor sublayer thickness and retinal pigment epithelium (RPE) layer thickness were used as structural biomarkers of AMD for 52 602 participants. We examined the associations of ambient air pollution with self-reported AMD and both photoreceptor sublayers and RPE layer thicknesses.

Results: After adjusting for covariates, people who were exposed to higher fine ambient particulate matter with an aerodynamic diameter <2.5 µm (PM, per IQR increase) had higher odds of self-reported AMD (OR=1.08, p=0.036), thinner photoreceptor synaptic region (β=-0.16 µm, p=2.0 × 10), thicker photoreceptor inner segment layer (β=0.04 µm, p=0.001) and thinner RPE (β=-0.13 µm, p=0.002). Higher levels of PM absorbance and NO were associated with thicker photoreceptor inner and outer segment layers, and a thinner RPE layer. Higher levels of PM (PM with an aerodynamic diameter <10 µm) was associated with thicker photoreceptor outer segment and thinner RPE, while higher exposure to NO was associated with thinner photoreceptor synaptic region.

Conclusion: Greater exposure to PM was associated with self-reported AMD, while PM, PM absorbance, PM, NO and NO were all associated with differences in retinal layer thickness.
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http://dx.doi.org/10.1136/bjophthalmol-2020-316218DOI Listing
January 2021

The genetic landscape of crystallins in congenital cataract.

Orphanet J Rare Dis 2020 11 26;15(1):333. Epub 2020 Nov 26.

Department of Genetics, UCL Institute of Ophthalmology, University College London, 11-43 Bath Street, London, EC1V 9EL, UK.

Background: The crystalline lens is mainly composed of a large family of soluble proteins called the crystallins, which are responsible for its development, growth, transparency and refractive index. Disease-causing sequence variants in the crystallins are responsible for nearly 50% of all non-syndromic inherited congenital cataracts, as well as causing cataract associated with other diseases, including myopathies. To date, more than 300 crystallin sequence variants causing cataract have been identified.

Methods: Here we aimed to identify the genetic basis of disease in five multi-generation British families and five sporadic cases with autosomal dominant congenital cataract using whole exome sequencing, with identified variants validated using Sanger sequencing. Following bioinformatics analysis, rare or novel variants with a moderate to damaging pathogenicity score, were filtered out and tested for segregation within the families.

Results: We have identified 10 different heterozygous crystallin variants. Five recurrent variants were found: family-A, with a missense variant (c.145C>T; p.R49C) in CRYAA associated with nuclear cataract; family-B, with a deletion in CRYBA1 (c.272delGAG; p.G91del) associated with nuclear cataract; and family-C, with a truncating variant in CRYGD (c.470G>A; W157*) causing a lamellar phenotype; individuals I and J had variants in CRYGC (c.13A>C; T5P) and in CRYGD (c.418C>T; R140*) causing unspecified congenital cataract and nuclear cataract, respectively. Five novel disease-causing variants were also identified: family D harboured a variant in CRYGC (c.179delG; R60Qfs*) responsible for a nuclear phenotype; family E, harboured a variant in CRYBB1 (c.656G>A; W219*) associated with lamellar cataract; individual F had a variant in CRYGD (c.392G>A; W131*) associated with nuclear cataract; and individuals G and H had variants in CRYAA (c.454delGCC; A152del) and in CRYBB1 (c.618C>A; Y206*) respectively, associated with unspecified congenital cataract. All novel variants were predicted to be pathogenic and to be moderately or highly damaging.

Conclusions: We report five novel variants and five known variants. Some are rare variants that have been reported previously in small ethnic groups but here we extend this to the wider population and record a broader phenotypic spectrum for these variants.
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http://dx.doi.org/10.1186/s13023-020-01613-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7691105PMC
November 2020

Response to: Comment on: Dark without pressure retinal changes in a paediatric age group.

Eye (Lond) 2021 11 3;35(11):3173. Epub 2020 Nov 3.

Department of Ophthalmology, University of California San Francisco School of Medicine, San Francisco, CA, USA.

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http://dx.doi.org/10.1038/s41433-020-01254-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8526819PMC
November 2021

Clinical and Genetic Findings in CTNNA1-Associated Macular Pattern Dystrophy.

Ophthalmology 2021 06 1;128(6):952-955. Epub 2020 Nov 1.

UCL Institute of Ophthalmology, University College London, London, United Kingdom; Moorfields Eye Hospital, London, United Kingdom; Section of Ophthalmology, King's College London, St. Thomas' Hospital, London, United Kingdom; Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom. Electronic address:

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http://dx.doi.org/10.1016/j.ophtha.2020.10.032DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8162661PMC
June 2021

Genetic Testing Leading to Early Identification of Childhood Ocular Manifestations of Usher Syndrome.

Laryngoscope 2021 06 28;131(6):E2053-E2059. Epub 2020 Oct 28.

Department of Otolaryngology - Head and Neck Surgery, University of California, San Francisco, California, U.S.A.

Objectives: Hearing-loss gene panel testing (HLGPT) is increasingly accessible as a first-line test in determining the etiology of sensorineural hearing loss (SNHL) in children. A major advantage of HLGPT is early identification of syndromic forms of SNHL, especially Usher syndrome, prior to the development of overt syndromic phenotype, which may impact management and counseling. Here, we describe early ocular findings in children with clinically non-syndromic SNHL identified by HLGPT as having two variants associated with Usher Syndrome.

Methods: A total of 184 children, ages 1 month - 15 years of age, evaluated at one tertiary pediatric children's hospital for clinically non-syndromic SNHL, underwent next-generation sequencing of 150 genes involved in hearing loss. Children with two variants in genes associated with Usher syndrome were referred for evaluation by pediatric ophthalmology.

Results: A total of 18/184 tested children had two variants in Usher syndrome-associated genes, including MYO7A, GPR98 (ADGRV1), USH2A, and PDZD7. SNHL varied from moderate to profound. 29% of the children who underwent clinical ophthalmology evaluation were found to have previously unidentified retinal abnormalities on retinal imaging or electroretinography consistent with inherited retinal degeneration.

Conclusion: Among this ethnically and racially diverse pediatric population with apparently non-syndromic SNHL, HLGPT yielded a high proportion (10%) of children with two variants in genes associated with Usher syndrome. Early genetic testing allows early identification of variants conferring a diagnosis of Usher syndrome at a stage prior to visual symptoms. This allows for more informed genetic counseling, reproductive planning, and sensory deficit interventions.

Level Of Evidence: 4 Laryngoscope, 131:E2053-E2059, 2021.
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http://dx.doi.org/10.1002/lary.29193DOI Listing
June 2021

The X-linked retinopathies: Physiological insights, pathogenic mechanisms, phenotypic features and novel therapies.

Prog Retin Eye Res 2021 05 26;82:100898. Epub 2020 Aug 26.

UCL Institute of Ophthalmology, University College London, UK; Moorfields Eye Hospital NHS Foundation Trust, London, UK; Department of Ophthalmology, Guy's & St Thomas' NHS Foundation Trust, London, UK; Section of Ophthalmology, King's College London, UK; Physiology, Development and Neuroscience, University of Cambridge, Cambridge, UK. Electronic address:

X-linked retinopathies represent a significant proportion of monogenic retinal disease. They include progressive and stationary conditions, with and without syndromic features. Many are X-linked recessive, but several exhibit a phenotype in female carriers, which can help establish diagnosis and yield insights into disease mechanisms. The presence of affected carriers can misleadingly suggest autosomal dominant inheritance. Some disorders (such as RPGR-associated retinopathy) show diverse phenotypes from variants in the same gene and also highlight limitations of current genetic sequencing methods. X-linked disease frequently arises from loss of function, implying potential for benefit from gene replacement strategies. We review X-inactivation and X-linked inheritance, and explore burden of disease attributable to X-linked genes in our clinically and genetically characterised retinal disease cohort, finding correlation between gene transcript length and numbers of families. We list relevant genes and discuss key clinical features, disease mechanisms, carrier phenotypes and novel experimental therapies. We consider in detail the following: RPGR (associated with retinitis pigmentosa, cone and cone-rod dystrophy), RP2 (retinitis pigmentosa), CHM (choroideremia), RS1 (X-linked retinoschisis), NYX (complete congenital stationary night blindness (CSNB)), CACNA1F (incomplete CSNB), OPN1LW/OPN1MW (blue cone monochromacy, Bornholm eye disease, cone dystrophy), GPR143 (ocular albinism), COL4A5 (Alport syndrome), and NDP (Norrie disease and X-linked familial exudative vitreoretinopathy (FEVR)). We use a recently published transcriptome analysis to explore expression by cell-type and discuss insights from electrophysiology. In the final section, we present an algorithm for genes to consider in diagnosing males with non-syndromic X-linked retinopathy, summarise current experimental therapeutic approaches, and consider questions for future research.
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http://dx.doi.org/10.1016/j.preteyeres.2020.100898DOI Listing
May 2021

Quantifying the Separation Between the Retinal Pigment Epithelium and Bruch's Membrane using Optical Coherence Tomography in Patients with Inherited Macular Degeneration.

Transl Vis Sci Technol 2020 05 23;9(6):26. Epub 2020 May 23.

Medical Retina Service, Moorfields Eye Hospital, London, UK.

Purpose: To describe and quantify Bruch's membrane (BM) and retinal pigment epithelium (RPE) separation using spectral-domain (SD) optical coherence tomography (OCT) in patients affected by inherited macular degenerations associated with BM thickening.

Methods: Patients with molecularly confirmed Sorsby fundus dystrophy (SFD), dominant drusen (DD), and late-onset retinal degeneration (L-ORD) were included in this retrospective study. Each disease was classed as early stage if subjects were asymptomatic, intermediate stage if they had nyctalopia alone, and late stage if they described loss of central vision. The main outcome was measurement of BM-RPE separation on SD-OCT. The BM-RPE separation measurements were compared against those in normal age-matched controls.

Results: Seventeen patients with SFD, 22 with DD, and eight with L-ORD were included. BM-RPE separation on SD-OCT demonstrated a high test-retest and interobserver reproducibility (intraclass correlation coefficients >0.9). BM-RPE separation was not identified in normal subjects. In SFD, there was greater BM-RPE separation in late-stage disease compared with intermediate-stage patients both at subfoveal ( < 0.05) and juxtafoveal ( < 0.01) locations. In DD, there was increased BM-RPE separation in late-stage disease compared with early stage at subfoveal ( < 0.001) and juxtafoveal ( < 0.05) topographies. There was no significant difference in BM-RPE separation between disease stages in L-ORD.

Conclusions: BM-RPE separation is a novel, quantifiable phenotype in the three monogenic macular dystrophies studied, and may be an optical correlate of the histopathological thickening in BM that is known to occur. BM-RPE separation, as measured by OCT, varies with stage of disease in SFD and DD, but not in L-ORD.

Translational Relevance: SFD, DD, and L-ORD are associated with BM thickening. In this group of patients, OCT assessment of macular structure identifies a separation of the usually single, hyperreflective line thought to represent BM and the overlying RPE. This separation is a novel and quantifiable feature of disease staging in SFD and DD.
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http://dx.doi.org/10.1167/tvst.9.6.26DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7409156PMC
May 2020

Exome sequencing in patients with microphthalmia, anophthalmia, and coloboma (MAC) from a consanguineous population.

Clin Genet 2020 11 3;98(5):499-506. Epub 2020 Sep 3.

Division of Genetics, Department of Pediatrics, University of California San Francisco, San Francisco, California, USA.

Next-generation sequencing strategies have resulted in mutation detection rates of 21% to 61% in small cohorts of patients with microphthalmia, anophthalmia and coloboma (MAC), but despite progress in identifying novel causative genes, many patients remain without a genetic diagnosis. We studied a cohort of 19 patients with MAC who were ascertained from a population with high rates of consanguinity. Using single nucleotide polymorphism (SNP) arrays and whole exome sequencing (WES), we identified one pathogenic variant in TENM3 in a patient with cataracts in addition to MAC. We also detected novel variants of unknown significance in genes that have previously been associated with MAC, including KIF26B, MICU1 and CDON, and identified variants in candidate genes for MAC from the Wnt signaling pathway, comprising LRP6, WNT2B and IQGAP1, but our findings do not prove causality. Plausible variants were not found for many of the cases, indicating that our current understanding of the pathogenesis of MAC, a highly heterogeneous group of ocular defects, remains incomplete.
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http://dx.doi.org/10.1111/cge.13830DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8077035PMC
November 2020

Genetic Basis of Inherited Retinal Disease in a Molecularly Characterized Cohort of More Than 3000 Families from the United Kingdom.

Ophthalmology 2020 10 16;127(10):1384-1394. Epub 2020 Apr 16.

UCL Institute of Ophthalmology, University College London, London, United Kingdom; Genetics Service, Moorfields Eye Hospital, London, United Kingdom; Section of Ophthalmology, King's College London, St. Thomas' Hospital Campus, London, United Kingdom; Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom. Electronic address:

Purpose: In a large cohort of molecularly characterized inherited retinal disease (IRD) families, we investigated proportions with disease attributable to causative variants in each gene.

Design: Retrospective study of electronic patient records.

Participants: Patients and relatives managed in the Genetics Service of Moorfields Eye Hospital in whom a molecular diagnosis had been identified.

Methods: Genetic screening used a combination of single-gene testing, gene panel testing, whole exome sequencing, and more recently, whole genome sequencing. For this study, genes listed in the Retinal Information Network online resource (https://sph.uth.edu/retnet/) were included. Transcript length was extracted for each gene (Ensembl, release 94).

Main Outcome Measures: We calculated proportions of families with IRD attributable to variants in each gene in the entire cohort, a cohort younger than 18 years, and a current cohort (at least 1 patient encounter between January 1, 2017, and August 2, 2019). Additionally, we explored correlation between numbers of families and gene transcript length.

Results: We identified 3195 families with a molecular diagnosis (variants in 135 genes), including 4236 affected individuals. The pediatric cohort comprised 452 individuals from 411 families (66 genes). The current cohort comprised 2614 families (131 genes; 3130 affected individuals). The 20 most frequently implicated genes overall (with prevalence rates per families) were as follows: ABCA4 (20.8%), USH2A (9.1%), RPGR (5.1%), PRPH2 (4.6%), BEST1 (3.9%), RS1 (3.5%), RP1 (3.3%), RHO (3.3%), CHM (2.7%), CRB1 (2.1%), PRPF31 (1.8%), MY07A (1.7%), OPA1 (1.6%), CNGB3 (1.4%), RPE65 (1.2%), EYS (1.2%), GUCY2D (1.2%), PROM1 (1.2%), CNGA3 (1.1%), and RDH12 (1.1%). These accounted for 71.8% of all molecularly diagnosed families. Spearman coefficients for correlation between numbers of families and transcript length were 0.20 (P = 0.025) overall and 0.27 (P = 0.017), -0.17 (P = 0.46), and 0.71 (P = 0.047) for genes in which variants exclusively cause recessive, dominant, or X-linked disease, respectively.

Conclusions: Our findings help to quantify the burden of IRD attributable to each gene. More than 70% of families showed pathogenic variants in 1 of 20 genes. Transcript length (relevant to gene delivery strategies) correlated significantly with numbers of affected families (but not for dominant disease).
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http://dx.doi.org/10.1016/j.ophtha.2020.04.008DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7520514PMC
October 2020

Whole Exome Sequencing Reveals Novel and Recurrent Disease-Causing Variants in Lens Specific Gap Junctional Protein Encoding Genes Causing Congenital Cataract.

Genes (Basel) 2020 05 6;11(5). Epub 2020 May 6.

UCL Institute of Ophthalmology, University College London, 11-43 Bath Street, London EC1V 9EL, UK.

Pediatric cataract is clinically and genetically heterogeneous and is the most common cause of childhood blindness worldwide. In this study, we aimed to identify disease-causing variants in three large British families and one isolated case with autosomal dominant congenital cataract, using whole exome sequencing. We identified four different heterozygous variants, three in the large families and one in the isolated case. Family A, with a novel missense variant (c.178G>C, p.Gly60Arg) in with lamellar cataract; family B, with a recurrent variant in (c.262C>T, p.Pro88Ser) associated with nuclear cataract; and family C, with a novel variant in (c.771dupC, p.Ser258GlnfsTer68) causing a lamellar phenotype. Individual D had a novel variant in (c.82G>T, p.Val28Leu) associated with congenital cataract. Each sequence variant was found to co-segregate with disease. Here, we report three novel and one recurrent disease-causing sequence variant in the gap junctional protein encoding genes causing autosomal dominant congenital cataract. Our study further extends the mutation spectrum of these genes and further facilitates clinical diagnosis. A recurrent p.P88S variant in causing isolated nuclear cataract provides evidence of further phenotypic heterogeneity associated with this variant.
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http://dx.doi.org/10.3390/genes11050512DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7288463PMC
May 2020

Congenital focal abnormalities of the retina and retinal pigment epithelium.

Eye (Lond) 2020 11 4;34(11):1973-1988. Epub 2020 May 4.

Department of Ophthalmology, University of California San Francisco, San Francisco, CA, USA.

This paper reviews the published literature on a group of developmental disorders of the retina and retinal pigment epithelium which result in focal abnormalities in one or both eyes. They are often asymptomatic, found on routine examination and are generally non-progressive. Some are associated with other systemic abnormalities.
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http://dx.doi.org/10.1038/s41433-020-0902-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7784997PMC
November 2020

An Improved Phenotype-Driven Tool for Rare Mendelian Variant Prioritization: Benchmarking Exomiser on Real Patient Whole-Exome Data.

Genes (Basel) 2020 04 23;11(4). Epub 2020 Apr 23.

William Harvey Research Institute, Queen Mary University of London, London EC1M 6BQ, UK.

Next-generation sequencing has revolutionized rare disease diagnostics, but many patients remain without a molecular diagnosis, particularly because many candidate variants usually survive despite strict filtering. Exomiser was launched in 2014 as a Java tool that performs an integrative analysis of patients' sequencing data and their phenotypes encoded with Human Phenotype Ontology (HPO) terms. It prioritizes variants by leveraging information on variant frequency, predicted pathogenicity, and gene-phenotype associations derived from human diseases, model organisms, and protein-protein interactions. Early published releases of Exomiser were able to prioritize disease-causative variants as top candidates in up to 97% of simulated whole-exomes. The size of the tested real patient datasets published so far are very limited. Here, we present the latest Exomiser version 12.0.1 with many new features. We assessed the performance using a set of 134 whole-exomes from patients with a range of rare retinal diseases and known molecular diagnosis. Using default settings, Exomiser ranked the correct diagnosed variants as the top candidate in 74% of the dataset and top 5 in 94%; not using the patients' HPO profiles (i.e., variant-only analysis) decreased the performance to 3% and 27%, respectively. In conclusion, Exomiser is an effective support tool for rare Mendelian phenotype-driven variant prioritization.
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http://dx.doi.org/10.3390/genes11040460DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7230372PMC
April 2020

Multiexon deletion alleles of ATF6 linked to achromatopsia.

JCI Insight 2020 04 9;5(7). Epub 2020 Apr 9.

Department of Ophthalmology, Stanford University, Stanford, California, USA.

Achromatopsia (ACHM) is an autosomal recessive disease that results in severe visual loss. Symptoms of ACHM include impaired visual acuity, nystagmus, and photoaversion starting from infancy; furthermore, ACHM is associated with bilateral foveal hypoplasia and absent or severely reduced cone photoreceptor function on electroretinography. Here, we performed genetic sequencing in 3 patients from 2 families with ACHM, identifying and functionally characterizing 2 mutations in the activating transcription factor 6 (ATF6) gene. We identified a homozygous deletion covering exons 8-14 of the ATF6 gene from 2 siblings from the same family. In another patient from a different family, we identified a heterozygous deletion covering exons 2 and 3 of the ATF6 gene found in trans with a previously identified ATF6 c.970C>T (p.Arg324Cys) ACHM disease allele. Recombinant ATF6 proteins bearing these exon deletions showed markedly impaired transcriptional activity by qPCR and RNA-Seq analysis compared with WT-ATF6. Finally, RNAscope revealed that ATF6 and the related ATF6B transcripts were expressed in cones as well as in all retinal layers in normal human retina. Overall, our data identify loss-of-function ATF6 disease alleles that cause human foveal disease.
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http://dx.doi.org/10.1172/jci.insight.136041DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7205249PMC
April 2020

A novel missense mutation in causing isolated autosomal dominant congenital cataract.

Ophthalmic Genet 2020 04 23;41(2):131-134. Epub 2020 Mar 23.

UCL Institute of Ophthalmology, University College London, London, UK.

: Congenital cataract is the most common cause of blindness in the world. Congenital cataracts are clinically and genetically heterogeneous and are mostly inherited in an autosomal dominant fashion. We identified the genetic cause of isolated autosomal dominant cataract in a four-generation British family and a Czech family.: Whole exome sequencing (WES) was performed on one affected member in the British family and two affected members in the Czech family.: A novel missense variant c.388C > T; p.(R130C) was identified in the Lens integral membrane protein (LIM2) and found to co-segregate with disease in both families.: Here we report the first autosomal dominant congenital cataract variant p.(R130C) in LIM2, causing a non-syndromic pulverulent and nuclear phenotype in European families.
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http://dx.doi.org/10.1080/13816810.2020.1737950DOI Listing
April 2020

Increased circulating levels of Factor H-Related Protein 4 are strongly associated with age-related macular degeneration.

Nat Commun 2020 02 7;11(1):778. Epub 2020 Feb 7.

Division of Evolution and Genomic Sciences, Faculty of Biology Medicine and Health, School of Biological Sciences, University of Manchester, Oxford Road, Manchester, M13 9PT, UK.

Age-related macular degeneration (AMD) is a leading cause of blindness. Genetic variants at the chromosome 1q31.3 encompassing the complement factor H (CFH, FH) and CFH related genes (CFHR1-5) are major determinants of AMD susceptibility, but their molecular consequences remain unclear. Here we demonstrate that FHR-4 plays a prominent role in AMD pathogenesis. We show that systemic FHR-4 levels are elevated in AMD (P-value = 7.1 × 10), whereas no difference is seen for FH. Furthermore, FHR-4 accumulates in the choriocapillaris, Bruch's membrane and drusen, and can compete with FH/FHL-1 for C3b binding, preventing FI-mediated C3b cleavage. Critically, the protective allele of the strongest AMD-associated CFH locus variant rs10922109 has the highest association with reduced FHR-4 levels (P-value = 2.2 × 10), independently of the AMD-protective CFHR1-3 deletion, and even in those individuals that carry the high-risk allele of rs1061170 (Y402H). Our findings identify FHR-4 as a key molecular player contributing to complement dysregulation in AMD.
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http://dx.doi.org/10.1038/s41467-020-14499-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7005798PMC
February 2020

The majority of autosomal recessive nanophthalmos and posterior microphthalmia can be attributed to biallelic sequence and structural variants in MFRP and PRSS56.

Sci Rep 2020 Jan 28;10(1):1289. Epub 2020 Jan 28.

Center for Medical Genetics, Ghent University and Ghent University Hospital, Ghent, Belgium.

This study aimed to genetically and clinically characterize a unique cohort of 25 individuals from 21 unrelated families with autosomal recessive nanophthalmos (NNO) and posterior microphthalmia (MCOP) from different ethnicities. An ophthalmological assessment in all families was followed by targeted MFRP and PRSS56 testing in 20 families and whole-genome sequencing in one family. Three families underwent homozygosity mapping using SNP arrays. Eight distinct MFRP mutations were found in 10/21 families (47.6%), five of which are novel including a deletion spanning the 5' untranslated region and the first coding part of exon 1. Most cases harbored homozygous mutations (8/10), while a compound heterozygous and a monoallelic genotype were identified in the remaining ones (2/10). Six distinct PRSS56 mutations were found in 9/21 (42.9%) families, three of which are novel. Similarly, homozygous mutations were found in all but one, leaving 2/21 families (9.5%) without a molecular diagnosis. Clinically, all patients had reduced visual acuity, hyperopia, short axial length and crowded optic discs. Retinitis pigmentosa was observed in 5/10 (50%) of the MFRP group, papillomacular folds in 12/19 (63.2%) of MCOP and in 3/6 (50%) of NNO cases. A considerable phenotypic variability was observed, with no clear genotype-phenotype correlations. Overall, our study represents the largest NNO and MCOP cohort reported to date and provides a genetic diagnosis in 19/21 families (90.5%), including the first MFRP genomic rearrangement, offering opportunities for gene-based therapies in MFRP-associated disease. Finally, our study underscores the importance of sequence and copy number analysis of the MFRP and PRSS56 genes in MCOP and NNO.
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http://dx.doi.org/10.1038/s41598-019-57338-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6987234PMC
January 2020

Recurrent heterozygous PAX6 missense variants cause severe bilateral microphthalmia via predictable effects on DNA-protein interaction.

Genet Med 2020 03 8;22(3):598-609. Epub 2019 Nov 8.

MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, UK.

Purpose: Most classical aniridia is caused by PAX6 haploinsufficiency. PAX6 missense variants can be hypomorphic or mimic haploinsufficiency. We hypothesized that missense variants also cause previously undescribed disease by altering the affinity and/or specificity of PAX6 genomic interactions.

Methods: We screened PAX6 in 372 individuals with bilateral microphthalmia, anophthalmia, or coloboma (MAC) from the Medical Research Council Human Genetics Unit eye malformation cohort (HGU) and reviewed data from the Deciphering Developmental Disorders study. We performed cluster analysis on PAX6-associated ocular phenotypes by variant type and molecular modeling of the structural impact of 86 different PAX6 causative missense variants.

Results: Eight different PAX6 missense variants were identified in 17 individuals (15 families) with MAC, accounting for 4% (15/372) of our cohort. Seven altered the paired domain (p.[Arg26Gln]x1, p.[Gly36Val]x1, p.[Arg38Trp]x2, p.[Arg38Gln]x1, p.[Gly51Arg]x2, p.[Ser54Arg]x2, p.[Asn124Lys]x5) and one the homeodomain (p.[Asn260Tyr]x1). p.Ser54Arg and p.Asn124Lys were exclusively associated with severe bilateral microphthalmia. MAC-associated variants were predicted to alter but not ablate DNA interaction, consistent with the electrophoretic mobility shifts observed using mutant paired domains with well-characterized PAX6-binding sites. We found no strong evidence for novel PAX6-associated extraocular disease.

Conclusion: Altering the affinity and specificity of PAX6-binding genome-wide provides a plausible mechanism for the worse-than-null effects of MAC-associated missense variants.
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http://dx.doi.org/10.1038/s41436-019-0685-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7056646PMC
March 2020

SSBP1 mutations in dominant optic atrophy with variable retinal degeneration.

Ann Neurol 2019 09 31;86(3):368-383. Epub 2019 Jul 31.

School of Optometry and Vision Sciences, Cardiff University, Cardiff, United Kingdom.

Objective: Autosomal dominant optic atrophy (ADOA) starts in early childhood with loss of visual acuity and color vision deficits. OPA1 mutations are responsible for the majority of cases, but in a portion of patients with a clinical diagnosis of ADOA, the cause remains unknown. This study aimed to identify novel ADOA-associated genes and explore their causality.

Methods: Linkage analysis and sequencing were performed in multigeneration families and unrelated patients to identify disease-causing variants. Functional consequences were investigated in silico and confirmed experimentally using the zebrafish model.

Results: We defined a new ADOA locus on 7q33-q35 and identified 3 different missense variants in SSBP1 (NM_001256510.1; c.113G>A [p.(Arg38Gln)], c.320G>A [p.(Arg107Gln)] and c.422G>A [p.(Ser141Asn)]) in affected individuals from 2 families and 2 singletons with ADOA and variable retinal degeneration. The mutated arginine residues are part of a basic patch that is essential for single-strand DNA binding. The loss of a positive charge at these positions is very likely to lower the affinity of SSBP1 for single-strand DNA. Antisense-mediated knockdown of endogenous ssbp1 messenger RNA (mRNA) in zebrafish resulted in compromised differentiation of retinal ganglion cells. A similar effect was achieved when mutated mRNAs were administered. These findings point toward an essential role of ssbp1 in retinal development and the dominant-negative nature of the identified human variants, which is consistent with the segregation pattern observed in 2 multigeneration families studied.

Interpretation: SSBP1 is an essential protein for mitochondrial DNA replication and maintenance. Our data have established pathogenic variants in SSBP1 as a cause of ADOA and variable retinal degeneration. ANN NEUROL 2019;86:368-383.
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http://dx.doi.org/10.1002/ana.25550DOI Listing
September 2019

Characterization of Retinal Structure in ATF6-Associated Achromatopsia.

Invest Ophthalmol Vis Sci 2019 06;60(7):2631-2640

Department of Ophthalmology & Visual Sciences, Medical College of Wisconsin, Milwaukee, Wisconsin, United States.

Purpose: Mutations in six genes have been associated with achromatopsia (ACHM): CNGA3, CNGB3, PDE6H, PDE6C, GNAT2, and ATF6. ATF6 is the most recent gene to be identified, though thorough phenotyping of this genetic subtype is lacking. Here, we sought to test the hypothesis that ATF6-associated ACHM is a structurally distinct form of congenital ACHM.

Methods: Seven genetically confirmed subjects from five nonconsanguineous families were recruited. Foveal hypoplasia and the integrity of the ellipsoid zone (EZ) band (a.k.a., IS/OS) were graded from optical coherence tomography (OCT) images. Images of the photoreceptor mosaic were acquired using confocal and nonconfocal split-detection adaptive optics scanning light ophthalmoscopy (AOSLO). Parafoveal cone and rod density values were calculated and compared to published normative data as well as data from two subjects harboring CNGA3 or CNGB3 mutations who were recruited for comparative purposes. Additionally, nonconfocal dark-field AOSLO images of the retinal pigment epithelium were obtained, with quantitative analysis performed in one subject with ATF6-ACHM.

Results: Foveal hypoplasia was observed in all subjects with ATF6 mutations. Absence of the EZ band within the foveal region (grade 3) or appearance of a hyporeflective zone (grade 4) was seen in all subjects with ATF6 using OCT. There was no evidence of remnant foveal cone structure using confocal AOSLO, although sporadic cone-like structures were seen in nonconfocal split-detection AOSLO. There was a lack of cone structure in the parafovea, in direct contrast to previous reports.

Conclusions: Our data demonstrate a near absence of cone structure in subjects harboring ATF6 mutations. This implicates ATF6 as having a major role in cone development and suggests that at least a subset of subjects with ATF6-ACHM have markedly fewer cellular targets for cone-directed gene therapies than do subjects with CNGA3- or CNGB3-ACHM.
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http://dx.doi.org/10.1167/iovs.19-27047DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6594318PMC
June 2019

Dysfunctional LAT2 Amino Acid Transporter Is Associated With Cataract in Mouse and Humans.

Front Physiol 2019 4;10:688. Epub 2019 Jun 4.

Institute of Medical Molecular Genetics, University of Zurich, Zurich, Switzerland.

Cataract, the loss of ocular lens transparency, accounts for ∼50% of worldwide blindness and has been associated with water and solute transport dysfunction across lens cellular barriers. We show that neutral amino acid antiporter LAT2 ) and uniporter TAT1 () are expressed on mouse ciliary epithelium and LAT2 also in lens epithelium. Correspondingly, deletion of LAT2 induced a dramatic decrease in lens essential amino acid levels that was modulated by TAT1 defect. Interestingly, the absence of LAT2 led to increased incidence of cataract in mice, in particular in older females, and a synergistic effect was observed with simultaneous lack of TAT1. Screening in patients diagnosed with congenital or age-related cataract yielded one homozygous single nucleotide deletion segregating in a family with congenital cataract. Expressed in HeLa cells, this LAT2 mutation did not support amino acid uptake. Heterozygous LAT2 variants were also found in patients with cataract some of which showed a reduced transport function when expressed in HeLa cells. Whether heterozygous LAT2 variants may contribute to the pathology of cataract needs to be further investigated. Overall, our results suggest that defects of amino acid transporter LAT2 are implicated in cataract formation, a situation that may be aggravated by TAT1 defects.
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http://dx.doi.org/10.3389/fphys.2019.00688DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6558864PMC
June 2019

Clinical and Molecular Characterization of Familial Exudative Vitreoretinopathy Associated With Microcephaly.

Am J Ophthalmol 2019 11 8;207:87-98. Epub 2019 May 8.

UCL Institute of Ophthalmology, University College London, London, United Kingdom; Moorfields Eye Hospital, London, United Kingdom. Electronic address:

Purpose: Familial exudative vitreoretinopathy (FEVR) is a rare finding in patients with genetic forms of microcephaly. This study documents the detailed phenotype and expands the range of genetic heterogeneity.

Design: Retrospective case series.

Methods: Twelve patients (10 families) with a diagnosis of FEVR and microcephaly were ascertained from pediatric genetic eye clinics and underwent full clinical assessment including retinal imaging. Molecular investigations included candidate gene Sanger sequencing, whole-exome sequencing (WES), and whole-genome sequencing (WGS).

Results: All patients had reduced vision and nystagmus. Six were legally blind. Two probands carried bi-allelic LRP5 variants, both presenting with bilateral retinal folds. A novel homozygous splice variant, and 2 missense variants were identified. Subsequent bone density measurement identified osteoporosis in one proband. Four families had heterozygous KIF11 variants. Two probands had a retinal fold in one eye and chorioretinal atrophy in the other; the other 2 had bilateral retinal folds. Four heterozygous variants were found, including 2 large deletions not identified on Sanger sequencing or WES. Finally, a family of 2 children with learning difficulties, abnormal peripheral retinal vasculogenesis, and rod-cone dystrophy were investigated. They were found to have bi-allelic splicing variants in TUBGCP6. Three families remain unsolved following WES and WGS.

Conclusions: Molecular diagnosis has been achieved in 7 of 10 families investigated, including a previously unrecognized association with LRP5. WGS enabled molecular diagnosis in 3 families after prior negative Sanger sequencing of the causative gene. This has enabled patient-specific care with targeted investigations and accurate family counseling.
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http://dx.doi.org/10.1016/j.ajo.2019.05.001DOI Listing
November 2019
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