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Tomlinson JW. Bardet-Biedl syndrome: A focus on genetics, mechanisms and metabolic dysfunction. Diabetes Obes Metab 2024; 26 Suppl 2:13-24. [PMID: 38302651 DOI: 10.1111/dom.15480] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/15/2023] [Revised: 01/18/2024] [Accepted: 01/18/2024] [Indexed: 02/03/2024]
Abstract
Bardet-Biedl syndrome (BBS) is a rare, monogenic, multisystem disorder characterized by retinal dystrophy, renal abnormalities, polydactyly, learning disabilities, as well as metabolic dysfunction, including obesity and an increased risk of type 2 diabetes. It is a primary ciliopathy, and causative mutations in more than 25 different genes have been described. Multiple cellular mechanisms contribute to the development of the metabolic phenotype associated with BBS, including hyperphagia as a consequence of altered hypothalamic appetite signalling as well as alterations in adipocyte biology promoting adipocyte proliferation and adipogenesis. Within this review, we describe in detail the metabolic phenotype associated with BBS and discuss the mechanisms that drive its evolution. In addition, we review current approaches to the metabolic management of patients with BBS, including the use of weight loss medications and bariatric surgery. Finally, we evaluate the potential of targeting hypothalamic appetite signalling to limit hyperphagia and induce clinically significant weight loss.
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Affiliation(s)
- Jeremy W Tomlinson
- Oxford Centre for Diabetes, Endocrinology and Metabolism, NIHR Oxford Biomedical Research Centre, University of Oxford, Churchill Hospital, Oxford, UK
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2
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Quadri N, Upadhyai P. Primary cilia in skeletal development and disease. Exp Cell Res 2023; 431:113751. [PMID: 37574037 DOI: 10.1016/j.yexcr.2023.113751] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Revised: 08/09/2023] [Accepted: 08/11/2023] [Indexed: 08/15/2023]
Abstract
Primary cilia are non-motile, microtubule-based sensory organelle present in most vertebrate cells with a fundamental role in the modulation of organismal development, morphogenesis, and repair. Here we focus on the role of primary cilia in embryonic and postnatal skeletal development. We examine evidence supporting its involvement in physiochemical and developmental signaling that regulates proliferation, patterning, differentiation and homeostasis of osteoblasts, chondrocytes, and their progenitor cells in the skeleton. We discuss how signaling effectors in mechanotransduction and bone development, such as Hedgehog, Wnt, Fibroblast growth factor and second messenger pathways operate at least in part at the primary cilium. The relevance of primary cilia in bone formation and maintenance is underscored by a growing list of rare genetic skeletal ciliopathies. We collate these findings and summarize the current understanding of molecular factors and mechanisms governing primary ciliogenesis and ciliary function in skeletal development and disease.
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Affiliation(s)
- Neha Quadri
- Department of Medical Genetics, Kasturba Medical College, Manipal, Manipal Academy of Higher Education, Manipal, India
| | - Priyanka Upadhyai
- Department of Medical Genetics, Kasturba Medical College, Manipal, Manipal Academy of Higher Education, Manipal, India.
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Leggatt GP, Seaby EG, Veighey K, Gast C, Gilbert RD, Ennis S. A Role for Genetic Modifiers in Tubulointerstitial Kidney Diseases. Genes (Basel) 2023; 14:1582. [PMID: 37628633 PMCID: PMC10454709 DOI: 10.3390/genes14081582] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Revised: 07/31/2023] [Accepted: 08/01/2023] [Indexed: 08/27/2023] Open
Abstract
With the increased availability of genomic sequencing technologies, the molecular bases for kidney diseases such as nephronophthisis and mitochondrially inherited and autosomal-dominant tubulointerstitial kidney diseases (ADTKD) has become increasingly apparent. These tubulointerstitial kidney diseases (TKD) are monogenic diseases of the tubulointerstitium and result in interstitial fibrosis and tubular atrophy (IF/TA). However, monogenic inheritance alone does not adequately explain the highly variable onset of kidney failure and extra-renal manifestations. Phenotypes vary considerably between individuals harbouring the same pathogenic variant in the same putative monogenic gene, even within families sharing common environmental factors. While the extreme end of the disease spectrum may have dramatic syndromic manifestations typically diagnosed in childhood, many patients present a more subtle phenotype with little to differentiate them from many other common forms of non-proteinuric chronic kidney disease (CKD). This review summarises the expanding repertoire of genes underpinning TKD and their known phenotypic manifestations. Furthermore, we collate the growing evidence for a role of modifier genes and discuss the extent to which these data bridge the historical gap between apparently rare monogenic TKD and polygenic non-proteinuric CKD (excluding polycystic kidney disease).
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Affiliation(s)
- Gary P. Leggatt
- Human Genetics & Genomic Medicine, University of Southampton, Southampton SO16 6YD, UK; (E.G.S.); (K.V.); (C.G.); (R.D.G.); (S.E.)
- Wessex Kidney Centre, Queen Alexandra Hospital, Portsmouth Hospitals NHS Trust, Portsmouth PO6 3LY, UK
- Renal Department, University Hospital Southampton, Southampton SO16 6YD, UK
| | - Eleanor G. Seaby
- Human Genetics & Genomic Medicine, University of Southampton, Southampton SO16 6YD, UK; (E.G.S.); (K.V.); (C.G.); (R.D.G.); (S.E.)
| | - Kristin Veighey
- Human Genetics & Genomic Medicine, University of Southampton, Southampton SO16 6YD, UK; (E.G.S.); (K.V.); (C.G.); (R.D.G.); (S.E.)
- Renal Department, University Hospital Southampton, Southampton SO16 6YD, UK
| | - Christine Gast
- Human Genetics & Genomic Medicine, University of Southampton, Southampton SO16 6YD, UK; (E.G.S.); (K.V.); (C.G.); (R.D.G.); (S.E.)
- Wessex Kidney Centre, Queen Alexandra Hospital, Portsmouth Hospitals NHS Trust, Portsmouth PO6 3LY, UK
| | - Rodney D. Gilbert
- Human Genetics & Genomic Medicine, University of Southampton, Southampton SO16 6YD, UK; (E.G.S.); (K.V.); (C.G.); (R.D.G.); (S.E.)
- Department of Paediatric Nephrology, Southampton Children’s Hospital, University Hospital Southampton NHS Foundation Trust, Southampton SO16 6YD, UK
| | - Sarah Ennis
- Human Genetics & Genomic Medicine, University of Southampton, Southampton SO16 6YD, UK; (E.G.S.); (K.V.); (C.G.); (R.D.G.); (S.E.)
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Tian X, Zhao H, Zhou J. Organization, functions, and mechanisms of the BBSome in development, ciliopathies, and beyond. eLife 2023; 12:e87623. [PMID: 37466224 DOI: 10.7554/elife.87623] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Accepted: 07/06/2023] [Indexed: 07/20/2023] Open
Abstract
The BBSome is an octameric protein complex that regulates ciliary transport and signaling. Mutations in BBSome subunits are closely associated with ciliary defects and lead to ciliopathies, notably Bardet-Biedl syndrome. Over the past few years, there has been significant progress in elucidating the molecular organization and functions of the BBSome complex. An improved understanding of BBSome-mediated biological events and molecular mechanisms is expected to help advance the development of diagnostic and therapeutic approaches for BBSome-related diseases. Here, we review the current literature on the structural assembly, transport regulation, and molecular functions of the BBSome, emphasizing its roles in cilium-related processes. We also provide perspectives on the pathological role of the BBSome in ciliopathies as well as how these can be exploited for therapeutic benefit.
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Affiliation(s)
- Xiaoyu Tian
- Center for Cell Structure and Function, Shandong Provincial Key Laboratory of Animal Resistance Biology, Collaborative Innovation Center of Cell Biology in Universities of Shandong, College of Life Sciences, Shandong Normal University, Jinan, China
| | - Huijie Zhao
- Center for Cell Structure and Function, Shandong Provincial Key Laboratory of Animal Resistance Biology, Collaborative Innovation Center of Cell Biology in Universities of Shandong, College of Life Sciences, Shandong Normal University, Jinan, China
| | - Jun Zhou
- Center for Cell Structure and Function, Shandong Provincial Key Laboratory of Animal Resistance Biology, Collaborative Innovation Center of Cell Biology in Universities of Shandong, College of Life Sciences, Shandong Normal University, Jinan, China
- State Key Laboratory of Medicinal Chemical Biology, Haihe Laboratory of Cell Ecosystem, College of Life Sciences, Nankai University, Tianjin, China
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Schönauer R, Jin W, Findeisen C, Valenzuela I, Devlin LA, Murrell J, Bedoukian EC, Pöschla L, Hantmann E, Riedhammer KM, Hoefele J, Platzer K, Biemann R, Campeau PM, Münch J, Heyne H, Hoffmann A, Ghosh A, Sun W, Dong H, Noé F, Wolfrum C, Woods E, Parker MJ, Neatu R, Le Guyader G, Bruel AL, Perrin L, Spiewak H, Missotte I, Fourgeaud M, Michaud V, Lacombe D, Paolucci SA, Buchan JG, Glissmeyer M, Popp B, Blüher M, Sayer JA, Halbritter J. Monoallelic intragenic POU3F2 variants lead to neurodevelopmental delay and hyperphagic obesity, confirming the gene's candidacy in 6q16.1 deletions. Am J Hum Genet 2023; 110:998-1007. [PMID: 37207645 PMCID: PMC10257002 DOI: 10.1016/j.ajhg.2023.04.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Revised: 04/25/2023] [Accepted: 04/28/2023] [Indexed: 05/21/2023] Open
Abstract
While common obesity accounts for an increasing global health burden, its monogenic forms have taught us underlying mechanisms via more than 20 single-gene disorders. Among these, the most common mechanism is central nervous system dysregulation of food intake and satiety, often accompanied by neurodevelopmental delay (NDD) and autism spectrum disorder. In a family with syndromic obesity, we identified a monoallelic truncating variant in POU3F2 (alias BRN2) encoding a neural transcription factor, which has previously been suggested as a driver of obesity and NDD in individuals with the 6q16.1 deletion. In an international collaboration, we identified ultra-rare truncating and missense variants in another ten individuals sharing autism spectrum disorder, NDD, and adolescent-onset obesity. Affected individuals presented with low-to-normal birth weight and infantile feeding difficulties but developed insulin resistance and hyperphagia during childhood. Except for a variant leading to early truncation of the protein, identified variants showed adequate nuclear translocation but overall disturbed DNA-binding ability and promotor activation. In a cohort with common non-syndromic obesity, we independently observed a negative correlation of POU3F2 gene expression with BMI, suggesting a role beyond monogenic obesity. In summary, we propose deleterious intragenic variants of POU3F2 to cause transcriptional dysregulation associated with hyperphagic obesity of adolescent onset with variable NDD.
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Affiliation(s)
- Ria Schönauer
- Department of Nephrology and Medical Intensive Care, Charité Universitätsmedizin Berlin, Berlin, Germany; Division of Nephrology, Endocrinology, Rheumatology, University of Leipzig Medical Center, Leipzig, Germany
| | - Wenjun Jin
- Division of Nephrology, Endocrinology, Rheumatology, University of Leipzig Medical Center, Leipzig, Germany
| | - Christin Findeisen
- Division of Nephrology, Endocrinology, Rheumatology, University of Leipzig Medical Center, Leipzig, Germany
| | | | - Laura Alice Devlin
- Translational and Clinical Research Institute, Newcastle University, Central Parkway, NE1 3BZ Newcastle, UK
| | - Jill Murrell
- Division of Genomic Diagnostics at Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Emma C Bedoukian
- Roberts Individualized Medical Genetics Center, Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Linda Pöschla
- Department of Nephrology and Medical Intensive Care, Charité Universitätsmedizin Berlin, Berlin, Germany
| | - Elena Hantmann
- Department of Nephrology and Medical Intensive Care, Charité Universitätsmedizin Berlin, Berlin, Germany
| | - Korbinian M Riedhammer
- Institute of Human Genetics, Klinikum rechts der Isar, Technical University Munich, School of Medicine, Munich, Germany; Department of Nephrology, Klinikum rechts der Isar, Technical University Munich, School of Medicine, Munich, Germany
| | - Julia Hoefele
- Institute of Human Genetics, Klinikum rechts der Isar, Technical University Munich, School of Medicine, Munich, Germany
| | - Konrad Platzer
- Institute of Human Genetics, University of Leipzig Medical Center, Leipzig, Germany
| | - Ronald Biemann
- Institute of Laboratory Medicine, Clinical Chemistry and Molecular Diagnostics, University Hospital Leipzig, Leipzig, Germany
| | - Philipp M Campeau
- Department of Pediatrics, University of Montreal, Montreal, QC, Canada
| | - Johannes Münch
- Department of Nephrology and Medical Intensive Care, Charité Universitätsmedizin Berlin, Berlin, Germany
| | - Henrike Heyne
- Hasso-Plattner-Institute, University of Potsdam, Potsdam, Germany; Hasso Plattner Institute for Digital Health at Mount Sinai School of Medicine, New York City, NY, USA; Institute for Molecular Medicine Finland: FIMM, University of Helsinki, Helsinki, Finland
| | - Anne Hoffmann
- Helmholtz Institute for Metabolic, Obesity and Vascular Research (HI-MAG) of the Helmholtz Zentrum München at the University of Leipzig and University Hospital Leipzig, Leipzig, Germany
| | - Adhideb Ghosh
- Institute of Food, Nutrition and Health, ETH Zurich, Schwerzenbach, Switzerland
| | - Wenfei Sun
- Institute of Food, Nutrition and Health, ETH Zurich, Schwerzenbach, Switzerland
| | - Hua Dong
- Institute of Food, Nutrition and Health, ETH Zurich, Schwerzenbach, Switzerland
| | - Falko Noé
- Institute of Food, Nutrition and Health, ETH Zurich, Schwerzenbach, Switzerland
| | - Christian Wolfrum
- Institute of Food, Nutrition and Health, ETH Zurich, Schwerzenbach, Switzerland
| | - Emily Woods
- Sheffield Children's NHS Foundation Trust, Sheffield, UK
| | | | - Ruxandra Neatu
- Translational and Clinical Research Institute, Newcastle University, Central Parkway, NE1 3BZ Newcastle, UK
| | - Gwenael Le Guyader
- Unité neurovasculaire et troubles cognitifs, University of Poitiers, Poitiers, France
| | - Ange-Line Bruel
- Equipe GAD, UMR1231 Inserm, Université de Bourgogne Franche Comté, Dijon, France
| | - Laurence Perrin
- UF de Génétique Clinique Département de Génétique, CHU Paris - Hôpital Robert Debré, Paris, France
| | - Helena Spiewak
- North East and Yorkshire Genomic Laboratory Hub, Central Laboratory, St. James's University Hospital, Leeds, UK
| | - Isabelle Missotte
- Service de Pédiatrie, Centre Hospitalier Territorial, Nouvelle Calédonie, France
| | - Melanie Fourgeaud
- Service de Génétique Médicale, Centre de Référence Anomalies du Développement et Syndrome Malformatifs, CHU de Bordeaux, France
| | - Vincent Michaud
- Service de Génétique Médicale, Centre de Référence Anomalies du Développement et Syndrome Malformatifs, CHU de Bordeaux, France; INSERM U1211, Maladies Rares: Génétique et Métabolisme (MRGM), Université de Bordeaux, Bordeaux, France
| | - Didier Lacombe
- Service de Génétique Médicale, Centre de Référence Anomalies du Développement et Syndrome Malformatifs, CHU de Bordeaux, France; INSERM U1211, Maladies Rares: Génétique et Métabolisme (MRGM), Université de Bordeaux, Bordeaux, France
| | - Sarah A Paolucci
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, WA, USA
| | - Jillian G Buchan
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, WA, USA
| | | | - Bernt Popp
- Berlin Institute of Health at Charité, Universitätsmedizin Berlin, Center of Functional Genomics, Berlin, Germany
| | - Matthias Blüher
- Helmholtz Institute for Metabolic, Obesity and Vascular Research (HI-MAG) of the Helmholtz Zentrum München at the University of Leipzig and University Hospital Leipzig, Leipzig, Germany
| | - John A Sayer
- Translational and Clinical Research Institute, Newcastle University, Central Parkway, NE1 3BZ Newcastle, UK; The Newcastle upon Tyne Hospitals NHS Foundation Trust, Freeman Road, NE7 7DN Newcastle, UK; NIHR Newcastle Biomedical Research Centre, NE4 5PL Newcastle, UK
| | - Jan Halbritter
- Department of Nephrology and Medical Intensive Care, Charité Universitätsmedizin Berlin, Berlin, Germany; Division of Nephrology, Endocrinology, Rheumatology, University of Leipzig Medical Center, Leipzig, Germany.
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D’Antona L, Amato R, Brescia C, Rocca V, Colao E, Iuliano R, Blazer-Yost BL, Perrotti N. Kinase Inhibitors in Genetic Diseases. Int J Mol Sci 2023; 24:ijms24065276. [PMID: 36982349 PMCID: PMC10048847 DOI: 10.3390/ijms24065276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Revised: 03/02/2023] [Accepted: 03/06/2023] [Indexed: 03/12/2023] Open
Abstract
Over the years, several studies have shown that kinase-regulated signaling pathways are involved in the development of rare genetic diseases. The study of the mechanisms underlying the onset of these diseases has opened a possible way for the development of targeted therapies using particular kinase inhibitors. Some of these are currently used to treat other diseases, such as cancer. This review aims to describe the possibilities of using kinase inhibitors in genetic pathologies such as tuberous sclerosis, RASopathies, and ciliopathies, describing the various pathways involved and the possible targets already identified or currently under study.
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Affiliation(s)
- Lucia D’Antona
- Department of Health Sciences, University “Magna Graecia” at Catanzaro, 88100 Catanzaro, Italy
- Medical Genetics Unit, University Hospital “Mater Domini” at Catanzaro, 88100 Catanzaro, Italy
| | - Rosario Amato
- Department of Health Sciences, University “Magna Graecia” at Catanzaro, 88100 Catanzaro, Italy
- Medical Genetics Unit, University Hospital “Mater Domini” at Catanzaro, 88100 Catanzaro, Italy
| | - Carolina Brescia
- Department of Health Sciences, University “Magna Graecia” at Catanzaro, 88100 Catanzaro, Italy
| | - Valentina Rocca
- Medical Genetics Unit, University Hospital “Mater Domini” at Catanzaro, 88100 Catanzaro, Italy
- Department of Experimental and Clinical Medicine, University “Magna Graecia” at Catanzaro, 88100 Catanzaro, Italy
| | - Emma Colao
- Medical Genetics Unit, University Hospital “Mater Domini” at Catanzaro, 88100 Catanzaro, Italy
| | - Rodolfo Iuliano
- Department of Health Sciences, University “Magna Graecia” at Catanzaro, 88100 Catanzaro, Italy
- Medical Genetics Unit, University Hospital “Mater Domini” at Catanzaro, 88100 Catanzaro, Italy
| | - Bonnie L. Blazer-Yost
- Department of Biology, Indiana University Purdue University, Indianapolis, IN 46202, USA
| | - Nicola Perrotti
- Department of Health Sciences, University “Magna Graecia” at Catanzaro, 88100 Catanzaro, Italy
- Medical Genetics Unit, University Hospital “Mater Domini” at Catanzaro, 88100 Catanzaro, Italy
- Correspondence:
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Tang VD, Egense A, Yiu G, Meyers E, Moshiri A, Shankar SP. Retinal dystrophies: A look beyond the eyes. Am J Ophthalmol Case Rep 2022; 27:101613. [PMID: 35756836 PMCID: PMC9228281 DOI: 10.1016/j.ajoc.2022.101613] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Revised: 05/10/2022] [Accepted: 06/09/2022] [Indexed: 11/27/2022] Open
Abstract
Purpose To illustrate the importance of systemic evaluation in retinal dystrophies through examples of Alstrom syndrome, Bardet Biedl syndrome, and Refsum disease. Observations Detailed eye evaluations, including visual acuity, visual field, slit lamp examination, and indirect ophthalmoscopy were performed. Retinal imaging included fundus photography and spectral domain optical coherence tomography (SD-OCT). Functional testing of the retina was done using full field electroretinography (ffERG). In addition, molecular genetic testing was performed using a ciliopathy panel, a retinal dystrophy panel, and whole genome sequencing (WGS). We report three individuals who presented with vision concerns first to ophthalmology, noted to have retinal dystrophy, and then referred to genomic medicine for genetic testing. Additional evaluation led to suspicion of specific groups of systemic disorders and guided appropriate genetic testing. The first individual presented with retinal dystrophy, obesity, and short stature with no reported neurocognitive deficits. Genetic testing included a ciliopathy panel that was negative followed by WGS that identified biallelic variants in ALMS: a novel frame-shift pathogenic variant c.6525dupT (p.Gln2176Serfs*17) and a rare nonsense pathogenic variant c.2035C > T (p.Arg679Ter) consistent with Alstrom syndrome. The second individual presented with retinal dystrophy, central obesity, and mild neurocognitive deficits. A ciliopathy genetic testing panel identified a homozygous pathogenic variant in BBS7: c.389_390del (p.Asn130Thrfs*4), confirming the diagnosis of Bardet Biedl syndrome. The third individual presented with progressive vision loss due to retinitis pigmentosa, anosmia, hearing loss, and shortened metatarsals and digits. Genetic testing identified two variants in PHYH: c.375_375del (p.Glu126Argfs*2) a pathogenic variant and c.536A > G (p.His179Arg), a variant of uncertain significance (VUS), suggestive of Refsum disease. Additional biochemical testing revealed markedly elevated phytanic acid with a low concentration of pristanic acid and normal concentrations of very long-chain fatty acids (C22:0, C24:0, C26:0), a pattern consistent with a diagnosis of Refsum disease. Conclusions and importance In individuals who present with retinal dystrophy to ophthalmologists, additional systemic manifestations such as sensorineural hearing loss, anosmia, or polydactyly, should be sought and a positive history or examination finding should prompt an immediate referral to a clinical geneticist for additional evaluation and appropriate genetic testing. This facilitates pre-test genetic counseling and allows for more accurate diagnosis, prognosis, and management of affected individuals along with better recurrence risk estimates for family members. Identification of an underlying etiology also enhances the understanding of the pathophysiology of disease and expands the genotypic and phenotypic spectrum. Ultimately, successful recognition of these diseases facilitates development of targeted therapies and surveillance of affected individuals.
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Nasser F, Kohl S, Kurtenbach A, Kempf M, Biskup S, Zuleger T, Haack TB, Weisschuh N, Stingl K, Zrenner E. Ophthalmic and Genetic Features of Bardet Biedl Syndrome in a German Cohort. Genes (Basel) 2022; 13:genes13071218. [PMID: 35886001 PMCID: PMC9322102 DOI: 10.3390/genes13071218] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2022] [Revised: 06/29/2022] [Accepted: 07/02/2022] [Indexed: 12/04/2022] Open
Abstract
The aim of this study was to characterize the ophthalmic and genetic features of Bardet Biedl (BBS) syndrome in a cohort of patients from a German specialized ophthalmic care center. Sixty-one patients, aged 5−56 years, underwent a detailed ophthalmic examination including visual acuity and color vision testing, electroretinography (ERG), visually evoked potential recording (VEP), fundus examination, and spectral domain optical coherence tomography (SD-OCT). Adaptive optics flood illumination ophthalmoscopy was performed in five patients. All patients had received diagnostic genetic testing and were selected upon the presence of apparent biallelic variants in known BBS-associated genes. All patients had retinal dystrophy with morphologic changes of the retina. Visual acuity decreased from ~0.2 (decimal) at age 5 to blindness 0 at 50 years. Visual field examination could be performed in only half of the patients and showed a concentric constriction with remaining islands of function in the periphery. ERG recordings were mostly extinguished whereas VEP recordings were reduced in about half of the patients. The cohort of patients showed 51 different likely biallelic mutations—of which 11 are novel—in 12 different BBS-associated genes. The most common associated genes were BBS10 (32.8%) and BBS1 (24.6%), and by far the most commonly observed variants were BBS10 c.271dup;p.C91Lfs*5 (21 alleles) and BBS1 c.1169T>G;p.M390R (18 alleles). The phenotype associated with the different BBS-associated genes and genotypes in our cohort is heterogeneous, with diverse features without genotype−phenotype correlation. The results confirm and expand our knowledge of this rare disease.
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Affiliation(s)
- Fadi Nasser
- Centre for Ophthalmology, University of Tübingen, 72076 Tuebingen, Germany; (S.K.); (A.K.); (M.K.); (N.W.); (K.S.); (E.Z.)
- Department of Ophthalmology, University of Leipzig, 04103 Leipzig, Germany
- Correspondence:
| | - Susanne Kohl
- Centre for Ophthalmology, University of Tübingen, 72076 Tuebingen, Germany; (S.K.); (A.K.); (M.K.); (N.W.); (K.S.); (E.Z.)
| | - Anne Kurtenbach
- Centre for Ophthalmology, University of Tübingen, 72076 Tuebingen, Germany; (S.K.); (A.K.); (M.K.); (N.W.); (K.S.); (E.Z.)
| | - Melanie Kempf
- Centre for Ophthalmology, University of Tübingen, 72076 Tuebingen, Germany; (S.K.); (A.K.); (M.K.); (N.W.); (K.S.); (E.Z.)
- Center for Rare Eye Diseases, University of Tübingen, 72076 Tuebingen, Germany
| | | | - Theresia Zuleger
- Institute of Medical Genetics and Applied Genomics, University of Tübingen, 72076 Tuebingen, Germany; (T.Z.); (T.B.H.)
| | - Tobias B. Haack
- Institute of Medical Genetics and Applied Genomics, University of Tübingen, 72076 Tuebingen, Germany; (T.Z.); (T.B.H.)
| | - Nicole Weisschuh
- Centre for Ophthalmology, University of Tübingen, 72076 Tuebingen, Germany; (S.K.); (A.K.); (M.K.); (N.W.); (K.S.); (E.Z.)
| | - Katarina Stingl
- Centre for Ophthalmology, University of Tübingen, 72076 Tuebingen, Germany; (S.K.); (A.K.); (M.K.); (N.W.); (K.S.); (E.Z.)
- Center for Rare Eye Diseases, University of Tübingen, 72076 Tuebingen, Germany
| | - Eberhart Zrenner
- Centre for Ophthalmology, University of Tübingen, 72076 Tuebingen, Germany; (S.K.); (A.K.); (M.K.); (N.W.); (K.S.); (E.Z.)
- Werner Reichardt Centre for Integrative Neuroscience (CIN), University of Tübingen, 72076 Tuebingen, Germany
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Abstract
The BBSome is an octameric protein complex involved in Bardet-Biedl syndrome (BBS), a human pleiotropic, autosomal recessive condition. Patients with BBS display various clinical features including obesity, hypertension, and renal abnormalities. Association studies have also linked the BBS genes to hypertension and other cardiovascular risks in the general population. The BBSome was originally associated with the function of cilia, a highly specialized organelle that extend from the cell membrane of most vertebrate cells. However, subsequent studies have implicated the BBSome in the control of a myriad of other cellular processes not related to cilia including cell membrane localization of receptors and gene expression. The development of animal models of BBS such as mouse lines lacking various components of the BBSome and associated proteins has facilitated studying their role in the control of cardiovascular function and deciphering the pathophysiological mechanisms responsible for the cardiovascular aberrations associated with BBS. These studies revealed the importance of the neuronal, renal, vascular, and cardiac BBSome in the regulation of blood pressure, renal function, vascular reactivity, and cardiac development. The BBSome has also emerged as a critical regulator of key systems involved in cardiovascular control including the renin-angiotensin system. Better understanding of the influence of the BBSome on the molecular and physiological processes relevant to cardiovascular health and disease has the potential of identifying novel mechanisms underlying hypertension and other cardiovascular risks.
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Affiliation(s)
- Yuying Zhao
- Department of Neuroscience and Pharmacology, University of Iowa Carver College of Medicine, Iowa City, IA, USA,Human Toxicology Graduate Program, University of Iowa Graduate College, Iowa City, IA, USA
| | - Kamal Rahmouni
- Department of Neuroscience and Pharmacology, University of Iowa Carver College of Medicine, Iowa City, IA, USA,Department of Internal Medicine, University of Iowa Carver College of Medicine, Iowa City, IA, USA,Fraternal Order of Eagles Diabetes Research Center, University of Iowa Carver College of Medicine, Iowa City, IA, USA,Obesity Research and Educational Initiative, University of Iowa Carver College of Medicine, Iowa City, IA, USA,Iowa City VA Health Care System, Iowa City, IA, USA,Corresponding author: Kamal Rahmouni, Ph.D., Department of Neuroscience and Pharmacology, University of Iowa Carver College of Medicine, Iowa City, IA, 52242, USA, , Tel: 319 353 5256, Fax: 319 353 5350
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10
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Xie C, Habif JC, Uytingco CR, Ukhanov K, Zhang L, de Celis C, Sheffield VC, Martens JR. Gene therapy rescues olfactory perception in a clinically relevant ciliopathy model of Bardet-Biedl syndrome. FASEB J 2021; 35:e21766. [PMID: 34383976 DOI: 10.1096/fj.202100627r] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Revised: 06/02/2021] [Accepted: 06/14/2021] [Indexed: 11/11/2022]
Abstract
Bardet-Biedl syndrome (BBS) is a hereditary genetic disorder that results in numerous clinical manifestations including olfactory dysfunction. Of at least 21 BBS-related genes that can carry multiple mutations, a pathogenic mutation, BBS1M390R, is the single most common mutation of clinically diagnosed BBS outcomes. While the deletion of BBS-related genes in mice can cause variable penetrance in different organ systems, the impact of the Bbs1M390R mutation in the olfactory system remains unclear. Using a clinically relevant knock-in mouse model homozygous for Bbs1M390R, we investigated the impact of the mutation on the olfactory system and tested the potential of viral-mediated, wildtype gene replacement therapy to rescue smell loss. The cilia of olfactory sensory neurons (OSNs) in Bbs1M390R/M390R mice were significantly shorter and fewer than those of wild-type mice. Also, both peripheral cellular odor detection and synaptic-dependent activity in the olfactory bulb were significantly decreased in the mutant mice. Furthermore, to gain insight into the degree to which perceptual features are impaired in the mutant mice, we used whole-body plethysmography to quantitatively measure odor-evoked sniffing. The Bbs1M390R/M390R mice showed significantly higher odor detection thresholds (reduced odor sensitivity) compared to wild-type mice; however, their odor discrimination acuity was still well maintained. Importantly, adenoviral expression of Bbs1 in OSNs restored cilia length and re-established both peripheral odorant detection and odor perception. Together, our findings further expand our understanding for the development of gene therapeutic treatment for congenital ciliopathies in the olfactory system.
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Affiliation(s)
- Chao Xie
- Department of Pharmacology and Therapeutics, University of Florida College of Medicine, Gainesville, FL, USA.,Center for Smell and Taste, University of Florida College of Medicine, Gainesville, FL, USA
| | - Julien C Habif
- Department of Pharmacology and Therapeutics, University of Florida College of Medicine, Gainesville, FL, USA.,Center for Smell and Taste, University of Florida College of Medicine, Gainesville, FL, USA
| | - Cedric R Uytingco
- Department of Pharmacology and Therapeutics, University of Florida College of Medicine, Gainesville, FL, USA.,Center for Smell and Taste, University of Florida College of Medicine, Gainesville, FL, USA
| | - Kirill Ukhanov
- Department of Pharmacology and Therapeutics, University of Florida College of Medicine, Gainesville, FL, USA.,Center for Smell and Taste, University of Florida College of Medicine, Gainesville, FL, USA
| | - Lian Zhang
- Department of Pharmacology and Therapeutics, University of Florida College of Medicine, Gainesville, FL, USA.,Center for Smell and Taste, University of Florida College of Medicine, Gainesville, FL, USA
| | - Carlos de Celis
- Department of Pharmacology and Therapeutics, University of Florida College of Medicine, Gainesville, FL, USA.,Center for Smell and Taste, University of Florida College of Medicine, Gainesville, FL, USA
| | - Val C Sheffield
- Division of Medical Genetics and Genomics, Department of Pediatrics, University of Iowa, Iowa City, IA, USA.,Department of Ophthalmology and Vision Research, University of Iowa, Iowa City, IA, USA
| | - Jeffrey R Martens
- Department of Pharmacology and Therapeutics, University of Florida College of Medicine, Gainesville, FL, USA.,Center for Smell and Taste, University of Florida College of Medicine, Gainesville, FL, USA
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11
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Aleman TS, O'Neil EC, O'Connor K, Jiang YY, Aleman IA, Bennett J, Morgan JIW, Toussaint BW. Bardet-Biedl syndrome-7 ( BBS7) shows treatment potential and a cone-rod dystrophy phenotype that recapitulates the non-human primate model. Ophthalmic Genet 2021; 42:252-265. [PMID: 33729075 DOI: 10.1080/13816810.2021.1888132] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Purpose: To provide a detailed ophthalmic phenotype of two male patients with Bardet-Biedl Syndrome (BBS) due to mutations in the BBS7 geneMethods: Two brothers ages 26 (Patient 1, P1) and 23 (P2) underwent comprehensive ophthalmic evaluations over three years. Visual function was assessed with full-field electroretinograms (ffERGs), kinetic and chromatic perimetry, multimodal imaging with spectral domain optical coherence tomography (SD-OCT), fundus autofluorescence (FAF) with short- (SW) and near-infrared (NIR) excitation lights and adaptive optics scanning light ophthalmoscopy (AOSLO).Results: Both siblings had a history of obesity and postaxial polydactyly; P2 had diagnoses of type 1 Diabetes Mellitus, Addison's disease, high-functioning autism-spectrum disorder and -12D myopia. Visual acuities were better than 20/30. Kinetic fields were moderately constricted. Cone-mediated ffERGs were undetectable, rod ERGs were ~80% of normal mean. Static perimetry showed severe central cone and rod dysfunction. Foveal to parafoveal hypoautofluorescence, most obvious on NIR-FAF, co-localized with outer segment shortening/loss and outer nuclear layer thinning by SD-OCT, and with reduced photoreceptors densities by AOSLO. A structural-functional dissociation was confirmed for cone- and rod-mediated parameters. Worsening of the above abnormalities was documented by SD-OCT and FAF in P2 at 3 years. Gene screening identified compound heterozygous mutations in BBS7 (p.Val266Glu: c.797 T > A of maternal origin; c.1781_1783delCAT, paternal) in both patients.Conclusions: BBS7-associated retinal degeneration may present as a progressive cone-rod dystrophy pattern, reminiscent of both the murine and non-human primate models of the disease. Predominantly central retinal abnormalities in both cone and rod photoreceptors showed a structural-functional dissociation, an ideal scenario for gene augmentation treatments.
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Affiliation(s)
- Tomas S Aleman
- Scheie Eye Institute at the Perelman Center for Advanced Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA.,Center for Advanced Retinal and Ocular Therapeutics, University of Pennsylvania, Philadelphia, Pennsylvania, USA.,Division of Ophthalmology of the Children's Hospital of Philadelphia, Department of Ophthalmology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Erin C O'Neil
- Scheie Eye Institute at the Perelman Center for Advanced Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA.,Center for Advanced Retinal and Ocular Therapeutics, University of Pennsylvania, Philadelphia, Pennsylvania, USA.,Division of Ophthalmology of the Children's Hospital of Philadelphia, Department of Ophthalmology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Keli O'Connor
- Scheie Eye Institute at the Perelman Center for Advanced Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA.,Center for Advanced Retinal and Ocular Therapeutics, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Yu You Jiang
- Scheie Eye Institute at the Perelman Center for Advanced Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA.,Center for Advanced Retinal and Ocular Therapeutics, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Isabella A Aleman
- Scheie Eye Institute at the Perelman Center for Advanced Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA.,Center for Advanced Retinal and Ocular Therapeutics, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Jean Bennett
- Scheie Eye Institute at the Perelman Center for Advanced Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA.,Center for Advanced Retinal and Ocular Therapeutics, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Jessica I W Morgan
- Scheie Eye Institute at the Perelman Center for Advanced Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA.,Center for Advanced Retinal and Ocular Therapeutics, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Brian W Toussaint
- Christiana Care Health System, Wilmington, Delaware, USA.,Department of Ophthalmology, Lewis Katz School of Medicine, Temple University, Philadelphia, Pennsylvania, USA
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12
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Hsu Y, Seo S, Sheffield VC. Photoreceptor cilia, in contrast to primary cilia, grant entry to a partially assembled BBSome. Hum Mol Genet 2021; 30:87-102. [PMID: 33517424 DOI: 10.1093/hmg/ddaa284] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2020] [Revised: 11/16/2020] [Accepted: 01/27/2021] [Indexed: 12/26/2022] Open
Abstract
The BBSome is a protein complex consisting of BBS1, BBS2, BBS4, BBS5, BBS7, BBS8, BBS9 and BBS18 that associates with intraflagellar transport complexes and specializes in ciliary trafficking. In primary cilia, ciliary entry requires the fully assembled BBSome as well as the small GTPase, ARL6 (BBS3). Retinal photoreceptors possess specialized cilia. In light of key structural and functional differences between primary and specialized cilia, we examined the principles of BBSome recruitment to photoreceptor cilia. We performed sucrose gradient fractionation using retinal lysates of Bbs2-/-, Bbs7-/-, Bbs8-/- and Bbs3-/- mice to determine the status of BBSome assembly, then determined localization of BBSome components using immunohistochemistry. Surprisingly, we found that a subcomplex of the BBSome containing at least BBS1, BBS5, BBS8 and BBS9 is recruited to cilia in the absence of BBS2 or BBS7. In contrast, a BBSome subcomplex consisting of BBS1, BBS2, BBS5, BBS7 and BBS9 is found in Bbs8-/- retinas and is denied ciliary entry in photoreceptor cells. In addition, the BBSome remains fully assembled in Bbs3-/- retinas and can be recruited to photoreceptor cilia in the absence of BBS3. We compared phenotypic severity of their retinal degeneration phenotypes. These findings demonstrate that unlike primary cilia, photoreceptor cilia admit a partially assembled BBSome meeting specific requirements. In addition, the recruitment of the BBSome to photoreceptor cilia does not require BBS3. These findings indicate that the ciliary entry of the BBSome is subjected to cell-specific regulation, particularly in cells with highly adapted forms of cilia such as photoreceptors.
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Affiliation(s)
- Ying Hsu
- Department of Pediatrics, Division of Medical Genetics and Genomics, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA
| | - Seongjin Seo
- Department of Ophthalmology and Visual Sciences, University of Iowa, Iowa City, IA 52242, USA
| | - Val C Sheffield
- Department of Pediatrics, Division of Medical Genetics and Genomics, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA
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13
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Novel Compound Heterozygous BBS2 and Homozygous MKKS Variants Detected in Chinese Families with Bardet-Biedl Syndrome. J Ophthalmol 2021; 2021:6751857. [PMID: 33520300 PMCID: PMC7817241 DOI: 10.1155/2021/6751857] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2020] [Revised: 10/23/2020] [Accepted: 12/19/2020] [Indexed: 11/29/2022] Open
Abstract
Background Bardet–Biedl syndrome (BBS) is a rare multisystem developmental disorder. In this study, we report the genetic causes and clinical manifestations in two Chinese families with BBS. Materials and Methods Two families were recruited in this study. Family A was a four-generation family with four affected and 15 unaffected members participating in the study, and family B was a consanguineous family with one affected and three unaffected members participating. Whole exome sequencing was performed in the two families, followed by a multistep bioinformatics analysis. Sanger sequencing was used to verify the variants and to perform a segregation analysis. Comprehensive ocular and systemic examinations were also conducted. Results Novel compound heterozygous variants c.235T > G (p.T79P) and c.534 + 1G > T were detected in the BBS2 gene in family A, and known homozygous variant c.748G > A (p.G250R) was detected in the MKKS gene in family B. Both families presented with retinitis pigmentosa; however, except for polydactyly, all other systemic manifestations were different. All of the affected family members in family A were overweight with a high body mass index (range from 26.5 to 41.9) and high blood pressure. Family A also presented with a delay in the onset of secondary sex characteristics and genital anomalies, while other systemic abnormalities were absent in family B. Conclusions This study presents one family with two novel BBS2 variants, expanding the variant spectrum of BBS, and one family with a known homozygous MKKS variant. The different phenotypes seen between the families with BBS2 and MKKS variants will contribute to the literature and our overall understanding of BBS.
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14
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The absence of BBSome function decreases synaptogenesis and causes ectopic synapse formation in the retina. Sci Rep 2020; 10:8321. [PMID: 32433491 PMCID: PMC7239920 DOI: 10.1038/s41598-020-65233-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Accepted: 04/25/2020] [Indexed: 11/09/2022] Open
Abstract
Photoreceptors possess ribbon synapses distinct from the conventional synapses in the brain. Little is known about the function of the BBSome, a complex integral in ciliary and intracellular trafficking, in ribbon synaptic formation. We performed immunohistochemistry using retinas from Bardet-Biedl Syndrome (BBS) mouse models and found that BBS mutant animals have significantly fewer ribbon synapses in the outer plexiform layer and increased ectopic synapses in the outer nuclear layer compared to controls. Many ectopic synapses in BBS mutant retinas are associated with horizontal cell axonal processes that aberrantly intrude into the outer nuclear layer. To determine whether this horizontal cell phenotype is a consequence of retinal degeneration, we examined this phenotype in mice with photoreceptor-specific inactivation of the BBSome induced by Cre recombinase driven by the rhodopsin promoter. At three months of age, despite retinal degeneration, Bbs8floxed/floxed; Rho-Cre+ mice lack the aberrant intrusion of horizontal cell processes. At 6 months, some horizontal cell processes intrude into the outer nuclear layer in Bbs8floxed/floxed; Rho-Cre+ mice, but the phenotype does not recapitulate the phenotypic severity observed in young congenital BBS mutant mice. Therefore, the lack of BBSome function negatively impacts retinal synaptogenesis, and causes horizontal cell defects in a potentially cell-autonomous fashion.
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15
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A novel missense variant in the BBS7 gene underlying Bardet-Biedl syndrome in a consanguineous Pakistani family. Clin Dysmorphol 2020; 29:17-23. [DOI: 10.1097/mcd.0000000000000294] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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16
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Peterson SM, McGill TJ, Puthussery T, Stoddard J, Renner L, Lewis AD, Colgin LMA, Gayet J, Wang X, Prongay K, Cullin C, Dozier BL, Ferguson B, Neuringer M. Bardet-Biedl Syndrome in rhesus macaques: A nonhuman primate model of retinitis pigmentosa. Exp Eye Res 2019; 189:107825. [PMID: 31589838 DOI: 10.1016/j.exer.2019.107825] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2019] [Revised: 09/27/2019] [Accepted: 09/30/2019] [Indexed: 11/15/2022]
Abstract
The development of therapies for retinal disorders is hampered by a lack of appropriate animal models. Higher nonhuman primates are the only animals with retinal structure similar to humans, including the presence of a macula and fovea. However, few nonhuman primate models of genetic retinal disease are known. We identified a lineage of rhesus macaques with a frameshift mutation in exon 3 of the BBS7 gene c.160delG (p.Ala54fs) that is predicted to produce a non-functional protein. In humans, mutations in this and other BBS genes cause Bardet-Biedl syndrome, a ciliopathy and a syndromic form of retinitis pigmentosa generally occurring in conjunction with kidney dysfunction, polydactyly, obesity, and/or hypogonadism. Three full- or half-sibling monkeys homozygous for the BBS7 c.160delG variant, at ages 3.5, 4 and 6 years old, displayed a combination of severe photoreceptor degeneration and progressive kidney disease. In vivo retinal imaging revealed features of severe macular degeneration, including absence of photoreceptor layers, degeneration of the retinal pigment epithelium, and retinal vasculature atrophy. Electroretinography in the 3.5-year-old case demonstrated loss of scotopic and photopic a-waves and markedly reduced and delayed b-waves. Histological assessments in the 4- and 6-year-old cases confirmed profound loss of photoreceptors and inner retinal neurons across the posterior retina, with dramatic thinning and disorganization of all cell layers, abundant microglia, absent or displaced RPE cells, and significant gliosis in the subretinal space. Retinal structure, including presence of photoreceptors, was preserved only in the far periphery. Ultrasound imaging of the kidneys revealed deranged architecture, and renal histopathology identified distorted contours with depressed, fibrotic foci and firmly adhered renal capsules; renal failure occurred in the 6-year-old case. Magnetic resonance imaging obtained in one case revealed abnormally low total brain volume and unilateral ventricular enlargement. The one male had abnormally small testes at 4 years of age, but polydactyly and obesity were not observed. Thus, monkeys homozygous for the BBS7 c.160delG variant closely mirrored several key features of the human BBS syndrome. This finding represents the first identification of a naturally-occurring nonhuman primate model of BBS, and more broadly the first such model of retinitis pigmentosa and a ciliopathy with an associated genetic mutation. This important new preclinical model will provide the basis for better understanding of disease progression and for the testing of new therapeutic options, including gene and cell-based therapies, not only for BBS but also for multiple forms of photoreceptor degeneration.
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Affiliation(s)
- Samuel M Peterson
- Division of Genetics, Oregon National Primate Research Center, Oregon Health & Sciences University, Beaverton, OR, 97006, USA.
| | - Trevor J McGill
- Division of Neuroscience, Oregon National Primate Research Center, Oregon Health & Sciences University, Beaverton, OR, 97006, USA; Casey Eye Institute, Oregon Health & Sciences University, Portland, OR, 97239, USA.
| | - Teresa Puthussery
- School of Optometry & Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA, 94720, USA.
| | - Jonathan Stoddard
- Division of Neuroscience, Oregon National Primate Research Center, Oregon Health & Sciences University, Beaverton, OR, 97006, USA.
| | - Lauren Renner
- Division of Neuroscience, Oregon National Primate Research Center, Oregon Health & Sciences University, Beaverton, OR, 97006, USA.
| | - Anne D Lewis
- Division of Comparative Medicine, Oregon National Primate Research Center, Oregon Health & Sciences University, Beaverton, OR, 97006, USA.
| | - Lois M A Colgin
- Division of Comparative Medicine, Oregon National Primate Research Center, Oregon Health & Sciences University, Beaverton, OR, 97006, USA.
| | - Jacqueline Gayet
- School of Optometry & Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA, 94720, USA.
| | - Xiaojie Wang
- Division of Neuroscience, Oregon National Primate Research Center, Oregon Health & Sciences University, Beaverton, OR, 97006, USA; Advanced Imaging Research Center, Oregon Health & Sciences University, Portland, OR, 97239, USA.
| | - Kamm Prongay
- Division of Comparative Medicine, Oregon National Primate Research Center, Oregon Health & Sciences University, Beaverton, OR, 97006, USA.
| | - Cassandra Cullin
- Division of Comparative Medicine, Oregon National Primate Research Center, Oregon Health & Sciences University, Beaverton, OR, 97006, USA.
| | - Brandy L Dozier
- Division of Comparative Medicine, Oregon National Primate Research Center, Oregon Health & Sciences University, Beaverton, OR, 97006, USA.
| | - Betsy Ferguson
- Division of Genetics, Oregon National Primate Research Center, Oregon Health & Sciences University, Beaverton, OR, 97006, USA; Department of Molecular and Medical Genetics, Oregon Health & Sciences University, Portland, OR, 97239, USA.
| | - Martha Neuringer
- Division of Neuroscience, Oregon National Primate Research Center, Oregon Health & Sciences University, Beaverton, OR, 97006, USA; Casey Eye Institute, Oregon Health & Sciences University, Portland, OR, 97239, USA.
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17
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Ludlam WG, Aoba T, Cuéllar J, Bueno-Carrasco MT, Makaju A, Moody JD, Franklin S, Valpuesta JM, Willardson BM. Molecular architecture of the Bardet-Biedl syndrome protein 2-7-9 subcomplex. J Biol Chem 2019; 294:16385-16399. [PMID: 31530639 DOI: 10.1074/jbc.ra119.010150] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Revised: 09/10/2019] [Indexed: 02/04/2023] Open
Abstract
Bardet-Biedl syndrome (BBS) is a genetic disorder characterized by malfunctions in primary cilia resulting from mutations that disrupt the function of the BBSome, an 8-subunit complex that plays an important role in protein transport in primary cilia. To better understand the molecular basis of BBS, here we used an integrative structural modeling approach consisting of EM and chemical cross-linking coupled with MS analyses, to analyze the structure of a BBSome 2-7-9 subcomplex consisting of three homologous BBS proteins, BBS2, BBS7, and BBS9. The resulting molecular model revealed an overall structure that resembles a flattened triangle. We found that within this structure, BBS2 and BBS7 form a tight dimer through a coiled-coil interaction and that BBS9 associates with the dimer via an interaction with the α-helical domain of BBS2. Interestingly, a BBS-associated mutation of BBS2 (R632P) is located in its α-helical domain at the interface between BBS2 and BBS9, and binding experiments indicated that this mutation disrupts the BBS2-BBS9 interaction. This finding suggests that BBSome assembly is disrupted by the R632P substitution, providing molecular insights that may explain the etiology of BBS in individuals harboring this mutation.
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Affiliation(s)
- W Grant Ludlam
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, Utah 84602
| | - Takuma Aoba
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, Utah 84602
| | - Jorge Cuéllar
- Centro Nacional de Biotecnología (CNB-CSIC), Campus de la Universidad Autónoma de Madrid, 28049 Madrid, Spain
| | - M Teresa Bueno-Carrasco
- Centro Nacional de Biotecnología (CNB-CSIC), Campus de la Universidad Autónoma de Madrid, 28049 Madrid, Spain
| | - Aman Makaju
- Department of Internal Medicine, Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, Utah 84112
| | - James D Moody
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, Utah 84602
| | - Sarah Franklin
- Department of Internal Medicine, Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, Utah 84112
| | - José M Valpuesta
- Centro Nacional de Biotecnología (CNB-CSIC), Campus de la Universidad Autónoma de Madrid, 28049 Madrid, Spain
| | - Barry M Willardson
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, Utah 84602
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18
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Manara E, Paolacci S, D’Esposito F, Abeshi A, Ziccardi L, Falsini B, Colombo L, Iarossi G, Pilotta A, Boccone L, Guerri G, Monica M, Marta B, Maltese PE, Buzzonetti L, Rossetti L, Bertelli M. Mutation profile of BBS genes in patients with Bardet-Biedl syndrome: an Italian study. Ital J Pediatr 2019; 45:72. [PMID: 31196119 PMCID: PMC6567512 DOI: 10.1186/s13052-019-0659-1] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Accepted: 05/16/2019] [Indexed: 01/20/2023] Open
Abstract
BACKGROUND Bardet-Biedl syndrome (BBS) is a rare inherited multisystemic disorder with autosomal recessive or complex digenic triallelic inheritance. There is currently no treatment for BBS, but some morbidities can be managed. Accurate molecular diagnosis is often crucial for the definition of appropriate patient management and for the development of a potential personalized therapy. METHODS We developed a next-generation-sequencing (NGS) protocol for the screening of the 18 most frequently mutated genes to define the genotype and clarify the mutation spectrum of a cohort of 20 BBS Italian patients. RESULTS We defined the causative variants in 60% of patients; four of those are novel. 33% of patients also harboured variants in additional gene/s, suggesting possible oligogenic inheritance. To explore the function of different genes, we looked for correlations between genotype and phenotype in our cohort. Hypogonadism was more frequently detected in patients with variants in BBSome proteins, while renal abnormalities in patients with variations in BBSome chaperonin genes. CONCLUSIONS NGS is a powerful tool that can help understanding BBS patients' phenotype through the identification of mutations that could explain differences in phenotype severity and could provide insights for the development of targeted therapy. Furthermore, our results support the existence of additional BBS loci yet to be identified.
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Affiliation(s)
| | | | - Fabiana D’Esposito
- Magi Euregio, Bolzano, Italy
- Imperial College Ophthalmic Research Unit, Western Eye Hospital, Imperial College Healthcare NHS Trust, London, UK
- Eye Clinic, Department of Neurosciences, Reproductive Sciences and Dentistry, Federico II University, Naples, Italy
| | | | | | - Benedetto Falsini
- Institute of Ophthalmology, Università Cattolica del Sacro Cuore, Rome, Italy
- Fondazione Policlinico Universitario “A. Gemelli”, IRCCS, Rome, Italy
| | - Leonardo Colombo
- Department of Ophthalmology, San Paolo Hospital, University of Milan, Milan, Italy
| | - Giancarlo Iarossi
- Department of Ophthalmology, Bambino Gesù IRCCS Children’s Hospital, Rome, Italy
| | - Alba Pilotta
- Special Unit of Auxoendocrinology, Diabetology and Pediatric Genetics, University of Brescia, Spedali Civili di Brescia, Brescia, Italy
| | - Loredana Boccone
- Microcitemic Regional Hospital, Brotzu Hospital, Cagliari, Italy
| | | | - Marica Monica
- Microcitemic Regional Hospital, Brotzu Hospital, Cagliari, Italy
| | - Balzarini Marta
- Microcitemic Regional Hospital, Brotzu Hospital, Cagliari, Italy
| | | | - Luca Buzzonetti
- Department of Ophthalmology, Bambino Gesù IRCCS Children’s Hospital, Rome, Italy
| | - Luca Rossetti
- Department of Ophthalmology, San Paolo Hospital, University of Milan, Milan, Italy
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19
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Shen T, Gao JM, Shou T, Li L, Zhang JP, Zhao Q, Yan XM. Identification of a homozygous BBS7 frameshift mutation in two (related) Chinese Miao families with Bardet-Biedl Syndrome. J Chin Med Assoc 2019; 82:110-114. [PMID: 30839500 DOI: 10.1097/jcma.0000000000000011] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
BACKGROUND Bardet-Biedl Syndrome (BBS) is a genetically heterogeneous autosomal recessive disorder with a wide spectrum of clinical features. To date, mutations in 21 different genes (BBS1-21) have been identified as causing isolated or complex BBS phenotypes. In this report, we present three Chinese Miao ethnic patients who were diagnosed with BBS on the basis of characteristic clinical features and investigated the exsome of these patients. METHODS To evaluate disease genes, the Agilent SureSelect system and Illumina HiSeq 2000 platform for whole exome enrichment and sequencing (WES) were used on the proband and her mother. Variants that fit a recessive model of inheritance only were compared and filtered using public databases. Variants detected by exome sequencing were validated by Sanger sequencing. A total of 981 phenotypically normal subjects were enrolled as control data set. RESULTS A frameshift homozygous germline mutation in BBS7 was detected by WES and identified by Sanger sequencing in affected individuals. This mutation was predicted to result in premature termination of exon5 (c.389_390delAC, p.Asn130ThrfsX3; RefSeq NM_176824.2) and lead to a 133 amino acid truncated protein. The inheritance patterns in the families are consistent with autosomal recessive inheritance, and no such homozygous mutation was found in the other 981 controls. CONCLUSION This mutation has not yet been described in any reported literature, and this is the first report on BBS7 mutation in Chinese Miao families with BBS phenotypes.
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Affiliation(s)
- Tao Shen
- Institute of Basic and Clinical Medicine, Key laboratory of Clinical Virology, Key Laboratory for Birth Defects and Genetic Diseases, the First People's Hospital of Yunnan Province, Kunming, Yunnan Province, China
| | - Jian-Mei Gao
- Institute of Basic and Clinical Medicine, Key laboratory of Clinical Virology, Key Laboratory for Birth Defects and Genetic Diseases, the First People's Hospital of Yunnan Province, Kunming, Yunnan Province, China
| | - Tao Shou
- Oncology Department, the First People's Hospital of Yunnan Province, Kunming, Yunnan Province, China
| | - Li Li
- Institute of Basic and Clinical Medicine, Key laboratory of Clinical Virology, Key Laboratory for Birth Defects and Genetic Diseases, the First People's Hospital of Yunnan Province, Kunming, Yunnan Province, China
| | - Jin-Ping Zhang
- Institute of Basic and Clinical Medicine, Key laboratory of Clinical Virology, Key Laboratory for Birth Defects and Genetic Diseases, the First People's Hospital of Yunnan Province, Kunming, Yunnan Province, China
| | - Qian Zhao
- Institute of Basic and Clinical Medicine, Key laboratory of Clinical Virology, Key Laboratory for Birth Defects and Genetic Diseases, the First People's Hospital of Yunnan Province, Kunming, Yunnan Province, China
| | - Xin-Min Yan
- Institute of Basic and Clinical Medicine, Key laboratory of Clinical Virology, Key Laboratory for Birth Defects and Genetic Diseases, the First People's Hospital of Yunnan Province, Kunming, Yunnan Province, China
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20
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Sheffield ID, McGee MA, Glenn SJ, Baek DY, Coleman JM, Dorius BK, Williams C, Rose BJ, Sanchez AE, Goodman MA, Daines JM, Eggett DL, Sheffield VC, Suli A, Kooyman DL. Osteoarthritis-Like Changes in Bardet-Biedl Syndrome Mutant Ciliopathy Mice ( Bbs1M390R/M390R): Evidence for a Role of Primary Cilia in Cartilage Homeostasis and Regulation of Inflammation. Front Physiol 2018; 9:708. [PMID: 29971011 PMCID: PMC6018413 DOI: 10.3389/fphys.2018.00708] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Accepted: 05/22/2018] [Indexed: 12/22/2022] Open
Abstract
Osteoarthritis (OA) is a debilitating inflammation related disease characterized by joint pain and effusion, loss of mobility, and deformity that may result in functional joint failure and significant impact on quality of life. Once thought of as a simple “wear and tear” disease, it is now widely recognized that OA has a considerable metabolic component and is related to chronic inflammation. Defects associated with primary cilia have been shown to be cause OA-like changes in Bardet–Biedl mice. We examined the role of dysfunctional primary cilia in OA in mice through the regulation of the previously identified degradative and pro-inflammatory molecular pathways common to OA. We observed an increase in the presence of pro-inflammatory markers TGFβ-1 and HTRA1 as well as cartilage destructive protease MMP-13 but a decrease in DDR-2. We observed a morphological difference in cartilage thickness in Bbs1M390R/M390R mice compared to wild type (WT). We did not observe any difference in OARSI or Mankin scores between WT and Bbs1M390R/M390R mice. Primary cilia appear to be involved in the upregulation of biomarkers, including pro-inflammatory markers common to OA.
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Affiliation(s)
- Isaac D Sheffield
- Department of Physiology and Developmental Biology, Brigham Young University, Provo, UT, United States
| | - Mercedes A McGee
- Department of Physiology and Developmental Biology, Brigham Young University, Provo, UT, United States
| | - Steven J Glenn
- Department of Physiology and Developmental Biology, Brigham Young University, Provo, UT, United States
| | - Da Young Baek
- Department of Physiology and Developmental Biology, Brigham Young University, Provo, UT, United States
| | - Joshua M Coleman
- Department of Physiology and Developmental Biology, Brigham Young University, Provo, UT, United States
| | - Bradley K Dorius
- Department of Physiology and Developmental Biology, Brigham Young University, Provo, UT, United States
| | - Channing Williams
- Department of Physiology and Developmental Biology, Brigham Young University, Provo, UT, United States
| | - Brandon J Rose
- Department of Physiology and Developmental Biology, Brigham Young University, Provo, UT, United States
| | - Anthony E Sanchez
- Department of Physiology and Developmental Biology, Brigham Young University, Provo, UT, United States
| | - Michael A Goodman
- Department of Physiology and Developmental Biology, Brigham Young University, Provo, UT, United States
| | - John M Daines
- Department of Physiology and Developmental Biology, Brigham Young University, Provo, UT, United States
| | - Dennis L Eggett
- Department of Physiology and Developmental Biology, Brigham Young University, Provo, UT, United States
| | - Val C Sheffield
- Departments of Pediatrics and Ophthalmology, University of Iowa, Iowa City, IA, United States
| | - Arminda Suli
- Department of Physiology and Developmental Biology, Brigham Young University, Provo, UT, United States
| | - David L Kooyman
- Department of Physiology and Developmental Biology, Brigham Young University, Provo, UT, United States
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21
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Biswas P, Duncan JL, Ali M, Matsui H, Naeem MA, Raghavendra PB, Frazer KA, Arts HH, Riazuddin S, Akram J, Hejtmancik JF, Riazuddin SA, Ayyagari R. A mutation in IFT43 causes non-syndromic recessive retinal degeneration. Hum Mol Genet 2018; 26:4741-4751. [PMID: 28973684 DOI: 10.1093/hmg/ddx356] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Accepted: 09/12/2017] [Indexed: 01/12/2023] Open
Abstract
The aim of this work is to identify the molecular cause of autosomal recessive early onset retinal degeneration in a consanguineous pedigree. Seventeen members of a four-generation Pakistani family were recruited and underwent a detailed ophthalmic examination. Exomes of four affected and two unaffected individuals were sequenced. Variants were filtered using exomeSuite to identify rare potentially pathogenic variants in genes expressed in the retina and/or brain and consistent with the pattern of inheritance. Effect of the variant observed in the gene Intraflagellar Transport Protein 43 (IFT43) was studied by heterologous expression in mIMCD3 and MDCK cells. Expression and sub-cellular localization of IFT43 in the retina and transiently transfected cells was examined by RT-PCR, western blot analysis, and immunohistochemistry. Affected members were diagnosed with early onset non-syndromic progressive retinal degeneration and the presence of bone spicules distributed throughout the retina at younger ages while the older affected members showed severe central choroidal atrophy. Whole-exome sequencing analysis identified a novel homozygous c.100 G > A change in IFT43 segregating with retinal degeneration and not present in ethnicity-matched controls. Immunostaining showed IFT43 localized in the photoreceptors, and to the tip of the cilia in transfected mIMCD3 and MDCK cells. The cilia in mIMCD3 and MDCK cells expressing mutant IFT43 were found to be significantly shorter (P < 0.001) than cells expressing wild-type IFT43. Our studies identified a novel homozygous mutation in the ciliary protein IFT43 as the underlying cause of recessive inherited retinal degeneration. This is the first report demonstrating the involvement of IFT43 in retinal degeneration.
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Affiliation(s)
- Pooja Biswas
- Shiley Eye Institute, University of California San Diego, La Jolla, CA, USA.,School of Biotechnology, REVA University, Bengaluru, Karnataka, India
| | - Jacque L Duncan
- Department of Ophthalmology, University of California San Francisco, San Francisco, CA, USA
| | - Muhammad Ali
- The Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Hiroko Matsui
- Institute for Genomic Medicine, University of California San Diego, La Jolla, CA, USA
| | - Muhammad Asif Naeem
- National Centre of Excellence in Molecular Biology, University of the Punjab, Lahore, Pakistan
| | - Pongali B Raghavendra
- School of Biotechnology, REVA University, Bengaluru, Karnataka, India.,School of Regenerative Medicine, Manipal University, Bangalore, India
| | - Kelly A Frazer
- Institute for Genomic Medicine, University of California San Diego, La Jolla, CA, USA.,Department of Pediatrics, Division of Genome Information Sciences, Rady Children's Hospital, San Diego, CA, USA
| | - Heleen H Arts
- Department of Pathology and Molecular Medicine, McMaster University, Hamilton, ON, Canada
| | - Sheikh Riazuddin
- National Centre of Excellence in Molecular Biology, University of the Punjab, Lahore, Pakistan.,Allama Iqbal Medical College, University of Health Sciences Lahore, Pakistan.,National Centre for Genetic Diseases, Shaheed Zulfiqar Ali Bhutto Medical University, Islamabad, Pakistan
| | - Javed Akram
- Allama Iqbal Medical College, University of Health Sciences Lahore, Pakistan.,National Centre for Genetic Diseases, Shaheed Zulfiqar Ali Bhutto Medical University, Islamabad, Pakistan
| | - J Fielding Hejtmancik
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, NIH, Bethesda, MD, USA
| | - S Amer Riazuddin
- The Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Radha Ayyagari
- Shiley Eye Institute, University of California San Diego, La Jolla, CA, USA
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22
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Robinson NA, Timmerhaus G, Baranski M, Andersen Ø, Takle H, Krasnov A. Training the salmon's genes: influence of aerobic exercise, swimming performance and selection on gene expression in Atlantic salmon. BMC Genomics 2017; 18:971. [PMID: 29246115 PMCID: PMC5731093 DOI: 10.1186/s12864-017-4361-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2016] [Accepted: 12/01/2017] [Indexed: 12/29/2022] Open
Abstract
BACKGROUND Farmed and wild Atlantic salmon are exposed to many infectious and non-infectious challenges that can cause mortality when they enter the sea. Exercise before transfer promotes growth, health and survival in the sea. Swimming performance in juveniles at the freshwater parr stage is positively associated with resistance to some diseases. Genetic variation is likely to affect response to exercise. In this study we map genetic differences associated with aerobic exercise, swimming performance and genetic origin. Eggs from the selectively bred Bolaks salmon and wild Lærdal River salmon strains were reared until parr in a common environment. Swimming performance was assessed by subjecting the fish to either continuous hard exercise or control conditions for 18 days. Heart was sampled for examination of gene expression using RNA-seq (~60 fish/treatment). RESULTS Lower expression of genes affecting immune function was found in domesticated than wild parr. Among wild parr under control exercise the expression of a large number of genes involved in general metabolism, stress and immune response was lower in superior swimmers suggesting that minimisation of energy expenditure during periods of low activity makes parr better able to sustain bursts of swimming for predator avoidance. A similar set of genes were down-regulated with training among wild parr with inferior swimming performance. These parr react to training in a way that their cardiac expression patterns become like the superior performing wild parr under control exercise conditions. Diversifying selection caused by breeding of domesticated stock, and adaptive pressures in wild stock, has affected the expression and frequency of single nucleotide polymorphisms (SNPs) for multiple functional groups of genes affecting diverse processes. SNPs associated with swimming performance in wild parr map to genes involved in energetic processes, coding for contractile filaments in the muscle and controlling cell proliferation. CONCLUSIONS Domesticated parr have less phenotypic plasticity in response to training and lower expression of genes with functions affecting immune response. The genetic response to training is complex and depends on the background of parr and their swimming ability. Exercise should be tailored to the genetics and swimming performance of fish.
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Affiliation(s)
- Nicholas A. Robinson
- Nofima, Osloveien 1, 1430 Ås, Norway
- Sustainable Aquaculture Laboratory - Temperate and Tropical (SALTT), School of BioSciences, The University of Melbourne, Parkville, Vic 3010 Australia
- Nofima, PO Box 210, 1431 Ås, Norway
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23
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Hsu Y, Garrison JE, Kim G, Schmitz AR, Searby CC, Zhang Q, Datta P, Nishimura DY, Seo S, Sheffield VC. BBSome function is required for both the morphogenesis and maintenance of the photoreceptor outer segment. PLoS Genet 2017; 13:e1007057. [PMID: 29049287 PMCID: PMC5663628 DOI: 10.1371/journal.pgen.1007057] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Revised: 10/31/2017] [Accepted: 10/08/2017] [Indexed: 01/19/2023] Open
Abstract
Genetic mutations disrupting the structure and function of primary cilia cause various inherited retinal diseases in humans. Bardet-Biedl syndrome (BBS) is a genetically heterogeneous, pleiotropic ciliopathy characterized by retinal degeneration, obesity, postaxial polydactyly, intellectual disability, and genital and renal abnormalities. To gain insight into the mechanisms of retinal degeneration in BBS, we developed a congenital knockout mouse of Bbs8, as well as conditional mouse models in which function of the BBSome (a protein complex that mediates ciliary trafficking) can be temporally inactivated or restored. We demonstrate that BBS mutant mice have defects in retinal outer segment morphogenesis. We further demonstrate that removal of Bbs8 in adult mice affects photoreceptor function and disrupts the structural integrity of the outer segment. Notably, using a mouse model in which a gene trap inhibiting Bbs8 gene expression can be removed by an inducible FLP recombinase, we show that when BBS8 is restored in immature retinas with malformed outer segments, outer segment extension can resume normally and malformed outer segment discs are displaced distally by normal outer segment structures. Over time, the retinas of the rescued mice become morphologically and functionally normal, indicating that there is a window of plasticity when initial retinal outer segment morphogenesis defects can be ameliorated. The BBSome is a protein complex that regulates ciliary trafficking in primary cilia, and mutations that impair BBSome function cause Bardet-Biedl Syndrome (BBS). BBS patients have retinal degeneration leading to blindness, but the disease pathophysiology has not been fully elucidated. In this study, we found that the BBSome is necessary for the structural organization of photoreceptor outer segments, and that the loss of different functional BBSome subunits causes outer segment malformation. Using a mouse model that allows the temporal inactivation of the BBSome, we inactivated BBSome function after the outer segment had formed normally. We found that the BBSome is required for both the initial formation and the continual maintenance of outer segment structures throughout life. In addition, using a mouse model that allows the temporal restoration of the BBSome, we restored BBSome function in immature photoreceptors and show that the malformed outer segment discs are displaced distally by normally formed outer segment structures. This finding indicates that when gene function is restored in immature retinas shortly after initial outer segment malformation, morphologically normal outer segments and a functionally normal retina can still result. This study has important implications for the timing of treatment of human retinal diseases.
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Affiliation(s)
- Ying Hsu
- Interdisciplinary Graduate Program in Molecular Medicine, University of Iowa, Iowa City, Iowa, United States
- Department of Pediatrics, University of Iowa, Iowa City, Iowa, United States
| | - Janelle E. Garrison
- Department of Pediatrics, University of Iowa, Iowa City, Iowa, United States
| | - Gunhee Kim
- Department of Pediatrics, University of Iowa, Iowa City, Iowa, United States
| | - Addison R. Schmitz
- Department of Pediatrics, University of Iowa, Iowa City, Iowa, United States
| | - Charles C. Searby
- Department of Pediatrics, University of Iowa, Iowa City, Iowa, United States
| | - Qihong Zhang
- Department of Pediatrics, University of Iowa, Iowa City, Iowa, United States
| | - Poppy Datta
- Department of Ophthalmology and Visual Sciences, University of Iowa, Iowa City, Iowa, United States
| | - Darryl Y. Nishimura
- Department of Pediatrics, University of Iowa, Iowa City, Iowa, United States
| | - Seongjin Seo
- Department of Ophthalmology and Visual Sciences, University of Iowa, Iowa City, Iowa, United States
| | - Val C. Sheffield
- Department of Pediatrics, University of Iowa, Iowa City, Iowa, United States
- Department of Ophthalmology and Visual Sciences, University of Iowa, Iowa City, Iowa, United States
- * E-mail:
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24
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Bujakowska KM, Liu Q, Pierce EA. Photoreceptor Cilia and Retinal Ciliopathies. Cold Spring Harb Perspect Biol 2017; 9:cshperspect.a028274. [PMID: 28289063 DOI: 10.1101/cshperspect.a028274] [Citation(s) in RCA: 121] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Photoreceptors are sensory neurons designed to convert light stimuli into neurological responses. This process, called phototransduction, takes place in the outer segments (OS) of rod and cone photoreceptors. OS are specialized sensory cilia, with analogous structures to those present in other nonmotile cilia. Deficient morphogenesis and/or dysfunction of photoreceptor sensory cilia (PSC) caused by mutations in a variety of photoreceptor-specific and common cilia genes can lead to inherited retinal degenerations (IRDs). IRDs can manifest as isolated retinal diseases or syndromic diseases. In this review, we describe the structure and composition of PSC and different forms of ciliopathies with retinal involvement. We review the genetics of the IRDs, which are monogenic disorders but genetically diverse with regard to causality.
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Affiliation(s)
- Kinga M Bujakowska
- Ocular Genomics Institute, Massachusetts Eye and Ear Infirmary, Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts 02114
| | - Qin Liu
- Ocular Genomics Institute, Massachusetts Eye and Ear Infirmary, Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts 02114
| | - Eric A Pierce
- Ocular Genomics Institute, Massachusetts Eye and Ear Infirmary, Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts 02114
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25
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Weihbrecht K, Goar WA, Pak T, Garrison JE, DeLuca AP, Stone EM, Scheetz TE, Sheffield VC. Keeping an Eye on Bardet-Biedl Syndrome: A Comprehensive Review of the Role of Bardet-Biedl Syndrome Genes in the Eye. MEDICAL RESEARCH ARCHIVES 2017; 5. [PMID: 29457131 DOI: 10.18103/mra.v5i9.1526] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Upwards of 90% of individuals with Bardet-Biedl syndrome (BBS) display rod-cone dystrophy with early macular involvement. BBS is an autosomal recessive, genetically heterogeneous, pleiotropic ciliopathy for which 21 causative genes have been discovered to date. In addition to retinal degeneration, the cardinal features of BBS include obesity, cognitive impairment, renal anomalies, polydactyly, and hypogonadism. Here, we review the genes, proteins, and protein complexes involved in BBS and the BBS model organisms available for the study of retinal degeneration. We include comprehensive lists for all known BBS genes, their known phenotypes, and the model organisms available. We also review the molecular mechanisms believed to lead to retinal degeneration. We provide an overview of the mode of inheritance and describe the relationships between BBS genes and Joubert syndrome, Leber Congenital Amaurosis, Senior-Løken syndrome, and non-syndromic retinitis pigmentosa. Finally, we propose ways that new advances in technology will allow us to better understand the role of different BBS genes in retinal formation and function.
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Affiliation(s)
- Katie Weihbrecht
- Department of Pediatrics, University of Iowa; Iowa City, IA 52242, USA.,Department of Ophthalmology and Visual Sciences, University of Iowa; Iowa City, IA 52242, USA.,Stephen A. Wynn Institute for Vision Research, University of Iowa; Iowa City, IA 52242, USA
| | - Wesley A Goar
- Department of Pediatrics, University of Iowa; Iowa City, IA 52242, USA.,Department of Ophthalmology and Visual Sciences, University of Iowa; Iowa City, IA 52242, USA.,Stephen A. Wynn Institute for Vision Research, University of Iowa; Iowa City, IA 52242, USA
| | - Thomas Pak
- Department of Pediatrics, University of Iowa; Iowa City, IA 52242, USA.,Stephen A. Wynn Institute for Vision Research, University of Iowa; Iowa City, IA 52242, USA
| | - Janelle E Garrison
- Department of Pediatrics, University of Iowa; Iowa City, IA 52242, USA.,Stephen A. Wynn Institute for Vision Research, University of Iowa; Iowa City, IA 52242, USA
| | - Adam P DeLuca
- Department of Ophthalmology and Visual Sciences, University of Iowa; Iowa City, IA 52242, USA.,Stephen A. Wynn Institute for Vision Research, University of Iowa; Iowa City, IA 52242, USA
| | - Edwin M Stone
- Department of Ophthalmology and Visual Sciences, University of Iowa; Iowa City, IA 52242, USA.,Stephen A. Wynn Institute for Vision Research, University of Iowa; Iowa City, IA 52242, USA
| | - Todd E Scheetz
- Department of Ophthalmology and Visual Sciences, University of Iowa; Iowa City, IA 52242, USA.,Stephen A. Wynn Institute for Vision Research, University of Iowa; Iowa City, IA 52242, USA
| | - Val C Sheffield
- Department of Pediatrics, University of Iowa; Iowa City, IA 52242, USA.,Department of Ophthalmology and Visual Sciences, University of Iowa; Iowa City, IA 52242, USA.,Stephen A. Wynn Institute for Vision Research, University of Iowa; Iowa City, IA 52242, USA
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26
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Priya S, Nampoothiri S, Sen P, Sripriya S. Bardet-Biedl syndrome: Genetics, molecular pathophysiology, and disease management. Indian J Ophthalmol 2017; 64:620-627. [PMID: 27853007 PMCID: PMC5151149 DOI: 10.4103/0301-4738.194328] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Primary cilia play a key role in sensory perception and various signaling pathways. Any defect in them leads to group of disorders called ciliopathies, and Bardet–Biedl syndrome (BBS, OMIM 209900) is one among them. The disorder is clinically and genetically heterogeneous, with various primary and secondary clinical manifestations, and shows autosomal recessive inheritance and highly prevalent in inbred/consanguineous populations. The disease mapped to at least twenty different genes (BBS1-BBS20), follow oligogenic inheritance pattern. BBS proteins localizes to the centerosome and regulates the biogenesis and functions of the cilia. In BBS, the functioning of various systemic organs (with ciliated cells) gets deranged and results in systemic manifestations. Certain components of the disease (such as obesity, diabetes, and renal problems) when noticed earlier offer a disease management benefit to the patients. However, the awareness of the disease is comparatively low and most often noticed only after severe vision loss in patients, which is usually in the first decade of the patient's age. In the current review, we have provided the recent updates retrieved from various types of scientific literature through journals, on the genetics, its molecular relevance, and the clinical outcome in BBS. The review in nutshell would provide the basic awareness of the disease that will have an impact in disease management and counseling benefits to the patients and their families.
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Affiliation(s)
- Sathya Priya
- SNONGC Department of Genetics and Molecular Biology, Kamal Nayan Institute for Research in Vision and Ophthalmology, Vision Research Foundation, Chennai, Tamil Nadu; School of Chemical and Biotechnology, SASTRA University, Thanjavur, Tamil Nadu, India
| | - Sheela Nampoothiri
- Department of Pediatric Genetics, Amrita Institute of Medical Sciences and Research Center, Cochin, Kerala, India
| | - Parveen Sen
- Department of Vitreoretina Clinic, Medical Research Foundation, Chennai, Tamil Nadu, India
| | - S Sripriya
- SNONGC Department of Genetics and Molecular Biology, Kamal Nayan Institute for Research in Vision and Ophthalmology, Vision Research Foundation, Chennai, Tamil Nadu, India
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27
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Genetic characterization and disease mechanism of retinitis pigmentosa; current scenario. 3 Biotech 2017; 7:251. [PMID: 28721681 DOI: 10.1007/s13205-017-0878-3] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Accepted: 07/10/2017] [Indexed: 12/21/2022] Open
Abstract
Retinitis pigmentosa is a group of genetically transmitted disorders affecting 1 in 3000-8000 individual people worldwide ultimately affecting the quality of life. Retinitis pigmentosa is characterized as a heterogeneous genetic disorder which leads by progressive devolution of the retina leading to a progressive visual loss. It can occur in syndromic (with Usher syndrome and Bardet-Biedl syndrome) as well as non-syndromic nature. The mode of inheritance can be X-linked, autosomal dominant or autosomal recessive manner. To date 58 genes have been reported to associate with retinitis pigmentosa most of them are either expressed in photoreceptors or the retinal pigment epithelium. This review focuses on the disease mechanisms and genetics of retinitis pigmentosa. As retinitis pigmentosa is tremendously heterogeneous disorder expressing a multiplicity of mutations; different variations in the same gene might induce different disorders. In recent years, latest technologies including whole-exome sequencing contributing effectively to uncover the hidden genesis of retinitis pigmentosa by reporting new genetic mutations. In future, these advancements will help in better understanding the genotype-phenotype correlations of disease and likely to develop new therapies.
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28
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Ullah A, Umair M, Yousaf M, Khan SA, Nazim-ud-din M, Shah K, Ahmad F, Azeem Z, Ali G, Alhaddad B, Rafique A, Jan A, Haack TB, Strom TM, Meitinger T, Ghous T, Ahmad W. Sequence variants in four genes underlying Bardet-Biedl syndrome in consanguineous families. Mol Vis 2017; 23:482-494. [PMID: 28761321 PMCID: PMC5524433] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2016] [Accepted: 07/19/2017] [Indexed: 12/03/2022] Open
Abstract
PURPOSE To investigate the molecular basis of Bardet-Biedl syndrome (BBS) in five consanguineous families of Pakistani origin. METHODS Linkage in two families (A and B) was established to BBS7 on chromosome 4q27, in family C to BBS8 on chromosome 14q32.1, and in family D to BBS10 on chromosome 12q21.2. Family E was investigated directly with exome sequence analysis. RESULTS Sanger sequencing revealed two novel mutations and three previously reported mutations in the BBS genes. These mutations include two deletions (c.580_582delGCA, c.1592_1597delTTCCAG) in the BBS7 gene, a missense mutation (p.Gln449His) in the BBS8 gene, a frameshift mutation (c.271_272insT) in the BBS10 gene, and a nonsense mutation (p.Ser40*) in the MKKS (BBS6) gene. CONCLUSIONS Two novel mutations and three previously reported variants, identified in the present study, further extend the body of evidence implicating BBS6, BBS7, BBS8, and BBS10 in causing BBS.
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Affiliation(s)
- Asmat Ullah
- Department of Biochemistry, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad, Pakistan
| | - Muhammad Umair
- Department of Biochemistry, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad, Pakistan,Institute of Human Genetics, Technische Universitat Munchen, Munchen, Germany,Institute of Human Genetics, Helmholtz Zentrum Munchen, Neuherberg, Germany
| | - Maryam Yousaf
- Department of Chemistry, University of Azad Jammu and Kashmir, Muzaffarabad, Pakistan
| | - Sher Alam Khan
- Kohat University of Science and Technology (KUST), Khyber Pakhtunkhwa Province, Pakistan
| | - Muhammad Nazim-ud-din
- Department of Biotechnology, University of Azad Jammu and Kashmir, Muzaffarabad, Pakistan
| | - Khadim Shah
- Department of Biochemistry, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad, Pakistan
| | - Farooq Ahmad
- Department of Biochemistry, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad, Pakistan
| | - Zahid Azeem
- Department of Chemistry, University of Azad Jammu and Kashmir, Muzaffarabad, Pakistan
| | - Ghazanfar Ali
- Department of Biotechnology, University of Azad Jammu and Kashmir, Muzaffarabad, Pakistan
| | - Bader Alhaddad
- Institute of Human Genetics, Technische Universitat Munchen, Munchen, Germany,Institute of Human Genetics, Helmholtz Zentrum Munchen, Neuherberg, Germany
| | - Afzal Rafique
- Department of Biochemistry, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad, Pakistan
| | - Abid Jan
- Department of Biochemistry, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad, Pakistan,Kohat University of Science and Technology (KUST), Khyber Pakhtunkhwa Province, Pakistan
| | - Tobias B. Haack
- Institute of Human Genetics, Technische Universitat Munchen, Munchen, Germany,Institute of Human Genetics, Helmholtz Zentrum Munchen, Neuherberg, Germany
| | - Tim M. Strom
- Institute of Human Genetics, Technische Universitat Munchen, Munchen, Germany,Institute of Human Genetics, Helmholtz Zentrum Munchen, Neuherberg, Germany
| | - Thomas Meitinger
- Institute of Human Genetics, Technische Universitat Munchen, Munchen, Germany,Institute of Human Genetics, Helmholtz Zentrum Munchen, Neuherberg, Germany
| | - Tahseen Ghous
- Department of Chemistry, University of Azad Jammu and Kashmir, Muzaffarabad, Pakistan
| | - Wasim Ahmad
- Department of Biochemistry, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad, Pakistan
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29
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Kaur Y, de Souza RJ, Gibson WT, Meyre D. A systematic review of genetic syndromes with obesity. Obes Rev 2017; 18:603-634. [PMID: 28346723 DOI: 10.1111/obr.12531] [Citation(s) in RCA: 104] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Revised: 02/01/2017] [Accepted: 02/02/2017] [Indexed: 11/29/2022]
Abstract
Syndromic monogenic obesity typically follows Mendelian patterns of inheritance and involves the co-presentation of other characteristics, such as mental retardation, dysmorphic features and organ-specific abnormalities. Previous reviews on obesity have reported 20 to 30 syndromes but no systematic review has yet been conducted on syndromic obesity. We searched seven databases using terms such as 'obesity', 'syndrome' and 'gene' to conduct a systematic review of literature on syndromic obesity. Our literature search identified 13,719 references. After abstract and full-text review, 119 relevant papers were eligible, and 42 papers were identified through additional searches. Our analysis of these 161 papers found that 79 obesity syndromes have been reported in literature. Of the 79 syndromes, 19 have been fully genetically elucidated, 11 have been partially elucidated, 27 have been mapped to a chromosomal region and for the remaining 22, neither the gene(s) nor the chromosomal location(s) have yet been identified. Interestingly, 54.4% of the syndromes have not been assigned a name, whereas 13.9% have more than one name. We report on organizational inconsistencies (e.g. naming discrepancies and syndrome classification) and provide suggestions for improvements. Overall, this review illustrates the need for increased clinical and genetic research on syndromes with obesity.
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Affiliation(s)
- Y Kaur
- Department of Health Research Methods, Evidence, and Impact, McMaster University, Hamilton, Canada
| | - R J de Souza
- Department of Health Research Methods, Evidence, and Impact, McMaster University, Hamilton, Canada
| | - W T Gibson
- Department of Medical Genetics, University of British Columbia, Vancouver, Canada.,British Columbia Children's Hospital Research Institute, Vancouver, Canada
| | - D Meyre
- Department of Health Research Methods, Evidence, and Impact, McMaster University, Hamilton, Canada.,Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Canada
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Recent progress in genetics, epigenetics and metagenomics unveils the pathophysiology of human obesity. Clin Sci (Lond) 2017; 130:943-86. [PMID: 27154742 DOI: 10.1042/cs20160136] [Citation(s) in RCA: 227] [Impact Index Per Article: 32.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Accepted: 02/24/2016] [Indexed: 12/19/2022]
Abstract
In high-, middle- and low-income countries, the rising prevalence of obesity is the underlying cause of numerous health complications and increased mortality. Being a complex and heritable disorder, obesity results from the interplay between genetic susceptibility, epigenetics, metagenomics and the environment. Attempts at understanding the genetic basis of obesity have identified numerous genes associated with syndromic monogenic, non-syndromic monogenic, oligogenic and polygenic obesity. The genetics of leanness are also considered relevant as it mirrors some of obesity's aetiologies. In this report, we summarize ten genetically elucidated obesity syndromes, some of which are involved in ciliary functioning. We comprehensively review 11 monogenic obesity genes identified to date and their role in energy maintenance as part of the leptin-melanocortin pathway. With the emergence of genome-wide association studies over the last decade, 227 genetic variants involved in different biological pathways (central nervous system, food sensing and digestion, adipocyte differentiation, insulin signalling, lipid metabolism, muscle and liver biology, gut microbiota) have been associated with polygenic obesity. Advances in obligatory and facilitated epigenetic variation, and gene-environment interaction studies have partly accounted for the missing heritability of obesity and provided additional insight into its aetiology. The role of gut microbiota in obesity pathophysiology, as well as the 12 genes associated with lipodystrophies is discussed. Furthermore, in an attempt to improve future studies and merge the gap between research and clinical practice, we provide suggestions on how high-throughput '-omic' data can be integrated in order to get closer to the new age of personalized medicine.
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31
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Nahum N, Forti E, Aksanov O, Birk R. Insulin regulates Bbs4 during adipogenesis. IUBMB Life 2017; 69:489-499. [PMID: 28371235 DOI: 10.1002/iub.1626] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2016] [Accepted: 03/12/2017] [Indexed: 01/08/2023]
Abstract
Bardet-Biedl syndrome (BBS) is a pleiotropic autosomal recessive disorder associated with marked obesity, increased susceptibility to insulin resistance and type 2 diabetes. However, it is unknown whether the link between BBS and diabetes is indirect or direct. Adipogenesis and adipocyte function are regulated by hormonal stimuli, with insulin and insulin growth factor (IGF) playing an important role both in normal and impaired conditions. We have previously shown augmented transcript levels of BBS genes upon induction of adipogenesis. The aim of this study was to investigate the role of insulin in BBS. Through in vitro studies in adipocytes in which Bbs4 expression was either silenced (SiBbs4) or overexpressed (OEBbs4), we showed that insulin and IGF dose- and time-dependently decrease transcription and protein expression of BBS genes during adipogenesis. Silencing of Bbs4 expression in adipocytes significantly impaired and reduced glucose uptake. This effect was reversed by Bbs4 overexpression. Inhibition of PI 3-kinase resulted in upregulation of Bbs transcripts, suggesting that the PI3K pathway is involved in the regulation of these genes. In conclusion, we showed that insulin is a direct regulator of Bbs1, 2, 4 and 6. This hormonal regulation might indicate a metabolic link of these genes to obesity and metabolic syndrome. © 2017 IUBMB Life, 69(7):489-499, 2017.
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Affiliation(s)
- Netta Nahum
- Department of Biotechnology and Epidemiology, Ben-Gurion University, Beer-Sheva, Israel.,Department of Nutrition, School of Health Science, Ariel University, Ariel, Israel
| | - Efrat Forti
- Department of Biotechnology and Epidemiology, Ben-Gurion University, Beer-Sheva, Israel
| | - Olga Aksanov
- Department of Biotechnology and Epidemiology, Ben-Gurion University, Beer-Sheva, Israel
| | - Ruth Birk
- Department of Nutrition, School of Health Science, Ariel University, Ariel, Israel
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Li Y, Hao H, Swerdel MR, Cho HY, Lee KB, Hart RP, Lyu YL, Cai L. Top2b is involved in the formation of outer segment and synapse during late-stage photoreceptor differentiation by controlling key genes of photoreceptor transcriptional regulatory network. J Neurosci Res 2017; 95:1951-1964. [PMID: 28370415 DOI: 10.1002/jnr.24037] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2016] [Revised: 01/26/2017] [Accepted: 01/27/2017] [Indexed: 01/17/2023]
Abstract
Topoisomerase II beta (Top2b) is an enzyme that alters the topologic states of DNA during transcription. Top2b deletion in early retinal progenitor cells causes severe defects in neural differentiation and affects cell survival in all retinal cell types. However, it is unclear whether the observed severe phenotypes are the result of cell-autonomous/primary defects or non-cell-autonomous/secondary defects caused by alterations of other retinal cells. Using photoreceptor cells as a model, we first characterized the phenotypes in Top2b conditional knockout. Top2b deletion leads to malformation of photoreceptor outer segments (OSs) and synapses accompanied by dramatic cell loss at late-stage photoreceptor differentiation. Then, we performed mosaic analysis with shRNA-mediated Top2b knockdown in neonatal retina using in vivo electroportation to target rod photoreceptors in neonatal retina. Top2b knockdown causes defective OS without causing a dramatic cell loss, suggesting a Top2b cell-autonomous function. Furthermore, RNA-seq analysis reveals that Top2b controls the expression of key genes in the photoreceptor gene-regulatory network (e.g., Crx, Nr2e3, Opn1sw, Vsx2) and retinopathy-related genes (e.g., Abca4, Bbs7, Pde6b). Together, our data establish a combinatorial cell-autonomous and non-cell-autonomous role for Top2b in the late stage of photoreceptor differentiation and maturation. © 2017 The Authors Journal of Neuroscience Research Published by Wiley Periodicals, Inc.
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Affiliation(s)
- Ying Li
- Department of Biomedical Engineering, Rutgers University, Piscataway, New Jersey
| | - Hailing Hao
- Department of Biomedical Engineering, Rutgers University, Piscataway, New Jersey
| | - Mavis R Swerdel
- Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, New Jersey
| | - Hyeon-Yeol Cho
- Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, New Jersey
| | - Ki-Bum Lee
- Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, New Jersey
| | - Ronald P Hart
- Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, New Jersey
| | - Yi Lisa Lyu
- Office of Research Commercialization, Rutgers University, Piscataway, New Jersey
| | - Li Cai
- Department of Biomedical Engineering, Rutgers University, Piscataway, New Jersey
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Garcia-Tizon Larroca S, Blagoeva Atanasova V, Orera Clemente M, Aluja Mendez A, Ortega Abad V, Perez Fernandez-Pacheco R, De León Luis J, Gamez Alderete F. Prenatal diagnosis of Bardet-Biedl syndrome in a case of hyperechogenic kidneys: Clinical use of DNA sequencing. Clin Case Rep 2017; 5:449-453. [PMID: 28396767 PMCID: PMC5378842 DOI: 10.1002/ccr3.859] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2016] [Revised: 10/18/2016] [Accepted: 01/20/2017] [Indexed: 01/17/2023] Open
Abstract
Bardet–Biedl syndrome (BBS) is a ciliopathy that is responsible for multiple visceral abnormalities. This disorder is defined by a combination of clinical signs, many of which appear after several years of development. BBS may be suspected antenatally based on routine ultrasound findings of enlarged hyperechogenic kidneys and postaxial polydactyly.
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Affiliation(s)
- Santiago Garcia-Tizon Larroca
- Fetal medicine unit Department of Obstetrics and Gynaecology Hospital General Universitario Gregorio Marañon Madrid Spain
| | - Vangeliya Blagoeva Atanasova
- Fetal medicine unit Department of Obstetrics and Gynaecology Hospital General Universitario Gregorio Marañon Madrid Spain
| | - Maria Orera Clemente
- Fetal medicine unit Department of Obstetrics and Gynaecology Hospital General Universitario Gregorio Marañon Madrid Spain
| | - Anna Aluja Mendez
- Fetal medicine unit Department of Obstetrics and Gynaecology Hospital General Universitario Gregorio Marañon Madrid Spain
| | - Virginia Ortega Abad
- Fetal medicine unit Department of Obstetrics and Gynaecology Hospital General Universitario Gregorio Marañon Madrid Spain
| | | | - Juan De León Luis
- Fetal medicine unit Department of Obstetrics and Gynaecology Hospital General Universitario Gregorio Marañon Madrid Spain
| | - Francisco Gamez Alderete
- Fetal medicine unit Department of Obstetrics and Gynaecology Hospital General Universitario Gregorio Marañon Madrid Spain
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Abstract
Nephronophthisis-related ciliopathies (NPHP-RC) are a group of inherited diseases that affect genes encoding proteins that localize to primary cilia or centrosomes. With few exceptions, ciliopathies are inherited in an autosomal recessive manner, and affected individuals manifest early during childhood or adolescence. NPHP-RC are genetically very heterogeneous, and, currently, mutations in more than 90 genes have been described as single-gene causes. The phenotypes of NPHP-RC are very diverse, and include cystic-fibrotic kidney disease, brain developmental defects, retinal degeneration, skeletal deformities, facial dimorphism, and, in some cases, laterality defects, and congenital heart disease. Mutations in the same gene can give rise to diverse phenotypes depending on the mutated allele. At the same time, there is broad phenotypic overlap between different monogenic genes. The identification of monogenic causes of ciliopathies has furthered the understanding of molecular mechanism and cellular pathways involved in the pathogenesis.
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Fine mapping a major obesity locus (jObes1) using a Berlin Fat Mouse × B6N advanced intercross population. Int J Obes (Lond) 2016; 40:1784-1788. [PMID: 27538457 DOI: 10.1038/ijo.2016.150] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Revised: 07/12/2016] [Accepted: 07/22/2016] [Indexed: 11/08/2022]
Abstract
BACKGROUND/OBJECTIVES The Berlin Fat Mouse Inbred line 860 is a model for juvenile obesity. Previously, a recessive major effect locus (jObes1) on chromosome 3 between 34 and 44 Mb has been found to be responsible for 39% of the variance of total fat mass at 10 weeks in a (BFMI860 x C57BL/6NCrl) F2 population. The aim of this study was fine mapping of the jObes1 locus. SUBJECTS/METHODS An advanced intercross line (AIL) was generated from the initial F2 mapping population. Three hundred and forty-four male mice of generation 28 were excessively phenotyped and genotyped using the MegaMuga mouse chip containing 22 164 informative single-nucleotide polymorphisms. Expression of candidate genes was investigated in gonadal adipose tissue, liver and whole brain from mice of different genotype classes. Classical genetic complementation tests were performed to test candidate genes. RESULTS The high mapping resolution of the AIL reduced the confidence interval for jObes1 from 10 to 0.37 Mb between 36.48 and 36.85 Mb. This region was highly significantly (logarithm (base 10) of odds (LOD) score after Benjamini and Hochberg correction (LOD(BH))>50) associated with total fat mass starting at puberty (6 weeks). Male homozygous carriers of the jObese1 BFMI allele had 3 g more fat than the other genotypes. Surprisingly, this genotype class showed lower body mass until weaning at 3 weeks (LOD(BH)=3.2). The mapped interval contains four genes. Bbs7, the most likely candidate gene that also caused obesity in the complementation test was differentially expressed in all tissues examined, whereas the neighboring cyclin A2 (Ccna2) gene showed differential expression in gonadal adipose tissue. CONCLUSIONS Using an AIL, the confidence interval for jObes1 could be 27-fold reduced by finding chromosomal recombinations. Although Bbs7 is the most likely obesity gene in the jObes1 region, neighboring genes cannot be entirely excluded. Further examinations are needed to enlighten the mechanism leading to physiological consequences on body mass and fat mass in juvenile animals.
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36
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Lindstrand A, Frangakis S, Carvalho C, Richardson E, McFadden K, Willer J, Pehlivan D, Liu P, Pediaditakis I, Sabo A, Lewis R, Banin E, Lupski J, Davis E, Katsanis N. Copy-Number Variation Contributes to the Mutational Load of Bardet-Biedl Syndrome. Am J Hum Genet 2016; 99:318-36. [PMID: 27486776 DOI: 10.1016/j.ajhg.2015.04.023] [Citation(s) in RCA: 97] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2015] [Accepted: 06/13/2016] [Indexed: 12/15/2022] Open
Abstract
Bardet-Biedl syndrome (BBS) is a defining ciliopathy, notable for extensive allelic and genetic heterogeneity, almost all of which has been identified through sequencing. Recent data have suggested that copy-number variants (CNVs) also contribute to BBS. We used a custom oligonucleotide array comparative genomic hybridization (aCGH) covering 20 genes that encode intraflagellar transport (IFT) components and 74 ciliopathy loci to screen 92 unrelated individuals with BBS, irrespective of their known mutational burden. We identified 17 individuals with exon-disruptive CNVs (18.5%), including 13 different deletions in eight BBS genes (BBS1, BBS2, ARL6/BBS3, BBS4, BBS5, BBS7, BBS9, and NPHP1) and a deletion and a duplication in other ciliopathy-associated genes (ALMS1 and NPHP4, respectively). By contrast, we found a single heterozygous exon-disruptive event in a BBS-associated gene (BBS9) in 229 control subjects. Superimposing these data with resequencing revealed CNVs to (1) be sufficient to cause disease, (2) Mendelize heterozygous deleterious alleles, and (3) contribute oligogenic alleles by combining point mutations and exonic CNVs in multiple genes. Finally, we report a deletion and a splice site mutation in IFT74, inherited under a recessive paradigm, defining a candidate BBS locus. Our data suggest that CNVs contribute pathogenic alleles to a substantial fraction of BBS-affected individuals and highlight how either deletions or point mutations in discrete splice isoforms can induce hypomorphic mutations in genes otherwise intolerant to deleterious variation. Our data also suggest that CNV analyses and resequencing studies unbiased for previous mutational burden is necessary to delineate the complexity of disease architecture.
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Abstract
Bardet-Biedl syndrome (BBS) is a rare autosomal recessive genetic disorder. It is characterized by heterogeneous clinical manifestations including primary features of the disease (rod-cone dystrophy, polydactyly, obesity, genital abnormalities, renal defects, and learning difficulties) and secondary BBS characteristics (developmental delay, speech deficit, brachydactyly or syndactyly, dental defects, ataxia or poor coordination, olfactory deficit, diabetes mellitus, congenital heart disease, etc.); most of these symptoms may not be present at birth but appear and progressively worsen during the first and second decades of life. At least 20 BBS genes have already been identified, and all of them are involved in primary cilia functioning. Genetic diagnosis of BBS is complicated due to lack of gene-specific disease symptoms; however, it is gradually becoming more accessible with the invention of multigene sequencing technologies. Clinical management of BBS is largely limited to a symptomatic treatment. Mouse experiments demonstrate that the most debilitating complication of BBS, blindness, can be rescued by topical gene therapy. There is a published case report describing the delay of BBS symptoms by nutritional compensation of the disease-related biochemical deficiencies. Progress in DNA testing technologies is likely to rapidly resolve all limitations in BBS diagnosis; however, much slower improvement is expected with regard to BBS treatment.
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Affiliation(s)
- Evgeny N Suspitsin
- N.N. Petrov Institute of Oncology, St. Petersburg, Russia; St. Petersburg Pediatric Medical University, St. Petersburg, Russia
| | - Evgeny N Imyanitov
- N.N. Petrov Institute of Oncology, St. Petersburg, Russia; St. Petersburg Pediatric Medical University, St. Petersburg, Russia; I.I. Mechnikov North-Western Medical University, St. Petersburg, Russia; St. Petersburg State University, St. Petersburg, Russia
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38
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Heon E, Kim G, Qin S, Garrison JE, Tavares E, Vincent A, Nuangchamnong N, Scott CA, Slusarski DC, Sheffield VC. Mutations in C8ORF37 cause Bardet Biedl syndrome (BBS21). Hum Mol Genet 2016; 25:2283-2294. [PMID: 27008867 DOI: 10.1093/hmg/ddw096] [Citation(s) in RCA: 82] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Accepted: 03/17/2016] [Indexed: 01/18/2023] Open
Abstract
Bardet Biedl syndrome (BBS) is a multisystem genetically heterogeneous ciliopathy that most commonly leads to obesity, photoreceptor degeneration, digit anomalies, genito-urinary abnormalities, as well as cognitive impairment with autism, among other features. Sequencing of a DNA sample from a 17-year-old female affected with BBS did not identify any mutation in the known BBS genes. Whole-genome sequencing identified a novel loss-of-function disease-causing homozygous mutation (K102*) in C8ORF37, a gene coding for a cilia protein. The proband was overweight (body mass index 29.1) with a slowly progressive rod-cone dystrophy, a mild learning difficulty, high myopia, three limb post-axial polydactyly, horseshoe kidney, abnormally positioned uterus and elevated liver enzymes. Mutations in C8ORF37 were previously associated with severe autosomal recessive retinal dystrophies (retinitis pigmentosa RP64 and cone-rod dystrophy CORD16) but not BBS. To elucidate the functional role of C8ORF37 in a vertebrate system, we performed gene knockdown in Danio rerio and assessed the cardinal features of BBS and visual function. Knockdown of c8orf37 resulted in impaired visual behavior and BBS-related phenotypes, specifically, defects in the formation of Kupffer's vesicle and delays in retrograde transport. Specificity of these phenotypes to BBS knockdown was shown with rescue experiments. Over-expression of human missense mutations in zebrafish also resulted in impaired visual behavior and BBS-related phenotypes. This is the first functional validation and association of C8ORF37 mutations with the BBS phenotype, which identifies BBS21. The zebrafish studies hereby show that C8ORF37 variants underlie clinically diagnosed BBS-related phenotypes as well as isolated retinal degeneration.
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Affiliation(s)
- Elise Heon
- Department of Ophthalmology and Vision Sciences, The Hospital for Sick Children, Toronto, M5G 1X8 Canada Department of Ophthalmology and Vision Sciences, University of Toronto, Toronto, M5G 1X8 Canada Program of Genetics and Genomic Biology, The Hospital for Sick Children, Toronto, M5G 1X8 Canada
| | - Gunhee Kim
- Department of Pediatrics, Division of Medical Genetics, Wynn Institute for Vision Research, Carver College of Medicine
| | - Sophie Qin
- Program of Genetics and Genomic Biology, The Hospital for Sick Children, Toronto, M5G 1X8 Canada
| | - Janelle E Garrison
- Department of Pediatrics, Division of Medical Genetics, Wynn Institute for Vision Research, Carver College of Medicine
| | - Erika Tavares
- Program of Genetics and Genomic Biology, The Hospital for Sick Children, Toronto, M5G 1X8 Canada
| | - Ajoy Vincent
- Department of Ophthalmology and Vision Sciences, The Hospital for Sick Children, Toronto, M5G 1X8 Canada Department of Ophthalmology and Vision Sciences, University of Toronto, Toronto, M5G 1X8 Canada
| | | | - C Anthony Scott
- Department of Biology, University of Iowa, Iowa City, IA 52242, USA
| | | | - Val C Sheffield
- Department of Pediatrics, Division of Medical Genetics, Wynn Institute for Vision Research, Carver College of Medicine
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Khan S, Muhammad N, Khan M, Kamal A, Rehman Z, Khan S. Genetics of human Bardet-Biedl syndrome, an updates. Clin Genet 2016; 90:3-15. [DOI: 10.1111/cge.12737] [Citation(s) in RCA: 98] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2015] [Revised: 12/21/2015] [Accepted: 01/03/2016] [Indexed: 12/22/2022]
Affiliation(s)
- S.A. Khan
- Department of Biotechnology and Genetic Engineering; Kohat University of Science and Technology; Khyber Pakhtunkhwa Pakistan
| | - N. Muhammad
- Department of Biotechnology and Genetic Engineering; Kohat University of Science and Technology; Khyber Pakhtunkhwa Pakistan
| | - M.A. Khan
- Gomal Centre of Biochemistry and Biotechnology; Gomal University; Khyber Pakhtunkhwa Pakistan
- Genomic Core Facility; Interim Translational Research Institute; Doha Qatar
| | - A. Kamal
- Department of Biotechnology and Genetic Engineering; Kohat University of Science and Technology; Khyber Pakhtunkhwa Pakistan
| | - Z.U. Rehman
- Department of Biotechnology and Genetic Engineering; Kohat University of Science and Technology; Khyber Pakhtunkhwa Pakistan
| | - S. Khan
- Department of Biotechnology and Genetic Engineering; Kohat University of Science and Technology; Khyber Pakhtunkhwa Pakistan
- Genomic Core Facility; Interim Translational Research Institute; Doha Qatar
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40
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Ece Solmaz A, Onay H, Atik T, Aykut A, Cerrah Gunes M, Ozalp Yuregir O, Bas VN, Hazan F, Kirbiyik O, Ozkinay F. Targeted multi-gene panel testing for the diagnosis of Bardet Biedl syndrome: Identification of nine novel mutations across BBS1, BBS2, BBS4, BBS7, BBS9, BBS10 genes. Eur J Med Genet 2015; 58:689-94. [DOI: 10.1016/j.ejmg.2015.10.011] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2015] [Revised: 10/19/2015] [Accepted: 10/23/2015] [Indexed: 12/19/2022]
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Guo J, Higginbotham H, Li J, Nichols J, Hirt J, Ghukasyan V, Anton ES. Developmental disruptions underlying brain abnormalities in ciliopathies. Nat Commun 2015. [PMID: 26206566 PMCID: PMC4515781 DOI: 10.1038/ncomms8857] [Citation(s) in RCA: 87] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Primary cilia are essential conveyors of signals underlying major cell functions. Cerebral cortical progenitors and neurons have a primary cilium. The significance of cilia function for brain development and function is evident in the plethora of developmental brain disorders associated with human ciliopathies. Nevertheless, the role of primary cilia function in corticogenesis remains largely unknown. Here we delineate the functions of primary cilia in the construction of cerebral cortex and their relevance to ciliopathies, using an shRNA library targeting ciliopathy genes known to cause brain disorders, but whose roles in brain development are unclear. We used the library to query how ciliopathy genes affect distinct stages of mouse cortical development, in particular neural progenitor development, neuronal migration, neuronal differentiation and early neuronal connectivity. Our results define the developmental functions of ciliopathy genes and delineate disrupted developmental events that are integrally related to the emergence of brain abnormalities in ciliopathies. Primary cilia are essential conveyors of signals underlying major cellular functions but their role in brain development is not completely understood. Here the authors compiled a shRNA library targeting ciliopathy genes known to cause brain disorders, and used it to query how ciliopathy genes affect distinct stages of mouse cortical development.
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Affiliation(s)
- Jiami Guo
- UNC Neuroscience Center and the Department of Cell Biology and Physiology, University of North Carolina School of Medicine, Chapel Hill, North Carolina 27599, USA
| | - Holden Higginbotham
- UNC Neuroscience Center and the Department of Cell Biology and Physiology, University of North Carolina School of Medicine, Chapel Hill, North Carolina 27599, USA
| | - Jingjun Li
- UNC Neuroscience Center and the Department of Cell Biology and Physiology, University of North Carolina School of Medicine, Chapel Hill, North Carolina 27599, USA
| | - Jackie Nichols
- UNC Neuroscience Center and the Department of Cell Biology and Physiology, University of North Carolina School of Medicine, Chapel Hill, North Carolina 27599, USA
| | - Josua Hirt
- UNC Neuroscience Center and the Department of Cell Biology and Physiology, University of North Carolina School of Medicine, Chapel Hill, North Carolina 27599, USA
| | - Vladimir Ghukasyan
- UNC Neuroscience Center and the Department of Cell Biology and Physiology, University of North Carolina School of Medicine, Chapel Hill, North Carolina 27599, USA
| | - E S Anton
- UNC Neuroscience Center and the Department of Cell Biology and Physiology, University of North Carolina School of Medicine, Chapel Hill, North Carolina 27599, USA
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Gholkar AA, Senese S, Lo YC, Capri J, Deardorff WJ, Dharmarajan H, Contreras E, Hodara E, Whitelegge JP, Jackson PK, Torres JZ. Tctex1d2 associates with short-rib polydactyly syndrome proteins and is required for ciliogenesis. Cell Cycle 2015; 14:1116-25. [PMID: 25830415 PMCID: PMC4614626 DOI: 10.4161/15384101.2014.985066] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2014] [Revised: 10/28/2014] [Accepted: 11/03/2014] [Indexed: 12/26/2022] Open
Abstract
Short-rib polydactyly syndromes (SRPS) arise from mutations in genes involved in retrograde intraflagellar transport (IFT) and basal body homeostasis, which are critical for cilia assembly and function. Recently, mutations in WDR34 or WDR60 (candidate dynein intermediate chains) were identified in SRPS. We have identified and characterized Tctex1d2, which associates with Wdr34, Wdr60 and other dynein complex 1 and 2 subunits. Tctex1d2 and Wdr60 localize to the base of the cilium and their depletion causes defects in ciliogenesis. We propose that Tctex1d2 is a novel dynein light chain important for trafficking to the cilium and potentially retrograde IFT and is a new molecular link to understanding SRPS pathology.
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Affiliation(s)
- Ankur A. Gholkar
- Department of Chemistry and Biochemistry; University of California; Los Angeles, CA USA
| | - Silvia Senese
- Department of Chemistry and Biochemistry; University of California; Los Angeles, CA USA
| | - Yu-Chen Lo
- Department of Chemistry and Biochemistry; University of California; Los Angeles, CA USA
- Program in Bioengineering; University of California; Los Angeles, CA USA
| | - Joseph Capri
- Pasarow Mass Spectrometry Laboratory; The Jane and Terry Semel Institute for Neuroscience and Human Behavior; David Geffen School of Medicine; University of California; Los Angeles, CA USA
| | - William J Deardorff
- Department of Chemistry and Biochemistry; University of California; Los Angeles, CA USA
| | - Harish Dharmarajan
- Department of Chemistry and Biochemistry; University of California; Los Angeles, CA USA
| | - Ely Contreras
- Department of Chemistry and Biochemistry; University of California; Los Angeles, CA USA
| | - Emmanuelle Hodara
- Department of Chemistry and Biochemistry; University of California; Los Angeles, CA USA
| | - Julian P Whitelegge
- Pasarow Mass Spectrometry Laboratory; The Jane and Terry Semel Institute for Neuroscience and Human Behavior; David Geffen School of Medicine; University of California; Los Angeles, CA USA
- Molecular Biology Institute; University of California; Los Angeles, CA USA
| | - Peter K Jackson
- Baxter Laboratory for Stem Cell Biology; Department of Microbiology & Immunology; Stanford University School of Medicine; Stanford, CA USA
| | - Jorge Z Torres
- Department of Chemistry and Biochemistry; University of California; Los Angeles, CA USA
- Molecular Biology Institute; University of California; Los Angeles, CA USA
- Jonsson Comprehensive Cancer Center; University of California; Los Angeles, CA USA
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43
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Keith BP, Robertson DL, Hentges KE. Locus heterogeneity disease genes encode proteins with high interconnectivity in the human protein interaction network. Front Genet 2014; 5:434. [PMID: 25538735 PMCID: PMC4260505 DOI: 10.3389/fgene.2014.00434] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2014] [Accepted: 11/24/2014] [Indexed: 01/20/2023] Open
Abstract
Mutations in genes potentially lead to a number of genetic diseases with differing severity. These disease genes have been the focus of research in recent years showing that the disease gene population as a whole is not homogeneous, and can be categorized according to their interactions. Locus heterogeneity describes a single disorder caused by mutations in different genes each acting individually to cause the same disease. Using datasets of experimentally derived human disease genes and protein interactions, we created a protein interaction network to investigate the relationships between the products of genes associated with a disease displaying locus heterogeneity, and use network parameters to suggest properties that distinguish these disease genes from the overall disease gene population. Through the manual curation of known causative genes of 100 diseases displaying locus heterogeneity and 397 single-gene Mendelian disorders, we use network parameters to show that our locus heterogeneity network displays distinct properties from the global disease network and a Mendelian network. Using the global human proteome, through random simulation of the network we show that heterogeneous genes display significant interconnectivity. Further topological analysis of this network revealed clustering of locus heterogeneity genes that cause identical disorders, indicating that these disease genes are involved in similar biological processes. We then use this information to suggest additional genes that may contribute to diseases with locus heterogeneity.
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Affiliation(s)
- Benjamin P Keith
- Faculty of Life Sciences, University of Manchester Manchester, UK
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44
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Chennen K, Scerbo MJ, Dollfus H, Poch O, Marion V. [Bardet-Biedl syndrome: cilia and obesity - from genes to integrative approaches]. Med Sci (Paris) 2014; 30:1034-1039. [PMID: 25388586 DOI: 10.1051/medsci/20143011018] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2023] Open
Abstract
The primary cilium is a specialized organelle, present at the surface of most eukaryotic cells, whose main function is to detect, integrate and transmit intra- and extra-cellular signals. Its dysfunction usually results in a group of severe clinical manifestations nowadays termed ciliopathies. The latter can be of syndromic nature with multi-organ dysfunctions and can also be associated with a morbid obese phenotype, like it is the case in the iconic ciliopathy, the Bardet Biedl syndrome (BBS). This review will discuss the contribution of the unique context offered by the emblematic BBS for understanding the mechanisms leading to obesity via the involvement of the primary cilium together with identification of novel molecular players and signaling pathways it has helped to highlight. In the current context of translational medicine and system biology, this article will also discuss the potential benefits and challenges posed by these techniques via multi-level approaches to better dissect the underlying mechanisms leading to the complex condition of obesity.
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Affiliation(s)
- Kirsley Chennen
- Laboratoire de génétique médicale, Inserm U1112, fédération de médecine translationnelle de Strasbourg (FMTS), Université de Strasbourg, 11, rue Humann, 67000 Strasbourg, France - LBGI bioinformatique et génomique intégratives - BFO ICube, CNRS UMR 7357, fédération de médecine translationnelle de Strasbourg (FMTS), Université de Strasbourg, 11, rue Humann, 67000 Strasbourg, France
| | - Maria Julia Scerbo
- Laboratoire de génétique médicale, Inserm U1112, fédération de médecine translationnelle de Strasbourg (FMTS), Université de Strasbourg, 11, rue Humann, 67000 Strasbourg, France
| | - Hélène Dollfus
- Laboratoire de génétique médicale, Inserm U1112, fédération de médecine translationnelle de Strasbourg (FMTS), Université de Strasbourg, 11, rue Humann, 67000 Strasbourg, France
| | - Olivier Poch
- LBGI bioinformatique et génomique intégratives - BFO ICube, CNRS UMR 7357, fédération de médecine translationnelle de Strasbourg (FMTS), Université de Strasbourg, 11, rue Humann, 67000 Strasbourg, France
| | - Vincent Marion
- Laboratoire de génétique médicale, Inserm U1112, fédération de médecine translationnelle de Strasbourg (FMTS), Université de Strasbourg, 11, rue Humann, 67000 Strasbourg, France
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45
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Aldahmesh MA, Li Y, Alhashem A, Anazi S, Alkuraya H, Hashem M, Awaji AA, Sogaty S, Alkharashi A, Alzahrani S, Al Hazzaa SA, Xiong Y, Kong S, Sun Z, Alkuraya FS. IFT27, encoding a small GTPase component of IFT particles, is mutated in a consanguineous family with Bardet-Biedl syndrome. Hum Mol Genet 2014; 23:3307-15. [PMID: 24488770 DOI: 10.1093/hmg/ddu044] [Citation(s) in RCA: 112] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Bardet-Biedl syndrome (BBS) is an autosomal recessive ciliopathy with multisystem involvement. So far, 18 BBS genes have been identified and the majority of them are essential for the function of BBSome, a protein complex involved in transporting membrane proteins into and from cilia. Yet defects in the identified genes cannot account for all the BBS cases. The genetic heterogeneity of this disease poses significant challenge to the identification of additional BBS genes. In this study, we coupled human genetics with functional validation in zebrafish and identified IFT27 as a novel BBS gene (BBS19). This is the first time an intraflagellar transport (IFT) gene is implicated in the pathogenesis of BBS, highlighting the genetic complexity of this disease.
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Affiliation(s)
| | | | - Amal Alhashem
- Deparment of Pediatrics, Prince Sultan Military Medical City, Riyadh, Saudi Arabia Department of Anatomy and Cell Biology, College of Medicine, Alfaisal University, Riyadh, Saudi Arabia
| | | | - Hisham Alkuraya
- Department of Ophthalmology, College of Medicine, Imam Muhammad Ibn Saud Islamic University, Riyadh, Saudi Arabia
| | | | - Ali A Awaji
- Department of Pediatrics, King Fahad Central Hospital, Jazan, Saudi Arabia
| | - Sameera Sogaty
- Department of Medical Genetics, King Fahad General Hospital, Jeddah, Saudi Arabia and
| | - Abdullah Alkharashi
- Deparment of Ophthalmology, College of Medicine, King Saud University, Riyadh, Saudi Arabia
| | - Saeed Alzahrani
- Department of Pediatric Nephrology, Prince Sultan Military Medical City, Riyadh, Saudi Arabia
| | - Selwa A Al Hazzaa
- Department of Ophthalmology, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia Department of Ophthalmology, College of Medicine, Alfaisal University, Riyadh, Saudi Arabia
| | - Yong Xiong
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
| | | | | | - Fowzan S Alkuraya
- Department of Genetics and Department of Anatomy and Cell Biology, College of Medicine, Alfaisal University, Riyadh, Saudi Arabia
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Wheway G, Parry DA, Johnson CA. The role of primary cilia in the development and disease of the retina. Organogenesis 2014; 10:69-85. [PMID: 24162842 PMCID: PMC4049897 DOI: 10.4161/org.26710] [Citation(s) in RCA: 98] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2013] [Revised: 10/01/2013] [Accepted: 10/04/2013] [Indexed: 02/07/2023] Open
Abstract
The normal development and function of photoreceptors is essential for eye health and visual acuity in vertebrates. Mutations in genes encoding proteins involved in photoreceptor development and function are associated with a suite of inherited retinal dystrophies, often as part of complex multi-organ syndromic conditions. In this review, we focus on the role of the photoreceptor outer segment, a highly modified and specialized primary cilium, in retinal health and disease. We discuss the many defects in the structure and function of the photoreceptor primary cilium that can cause a class of inherited conditions known as ciliopathies, often characterized by retinal dystrophy and degeneration, and highlight the recent insights into disease mechanisms.
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Affiliation(s)
- Gabrielle Wheway
- Section of Ophthalmology and Neurosciences; Leeds Institute of Molecular Medicine; The University of Leeds; Leeds, United Kingdom
| | - David A Parry
- Section of Genetics; Leeds Institute of Molecular Medicine; The University of Leeds; Leeds, United Kingdom
| | - Colin A Johnson
- Section of Ophthalmology and Neurosciences; Leeds Institute of Molecular Medicine; The University of Leeds; Leeds, United Kingdom
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47
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van der Velde KJ, de Haan M, Zych K, Arends D, Snoek LB, Kammenga JE, Jansen RC, Swertz MA, Li Y. WormQTLHD--a web database for linking human disease to natural variation data in C. elegans. Nucleic Acids Res 2013; 42:D794-801. [PMID: 24217915 PMCID: PMC3965109 DOI: 10.1093/nar/gkt1044] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Interactions between proteins are highly conserved across species. As a result, the molecular basis of multiple diseases affecting humans can be studied in model organisms that offer many alternative experimental opportunities. One such organism—Caenorhabditis elegans—has been used to produce much molecular quantitative genetics and systems biology data over the past decade. We present WormQTLHD (Human Disease), a database that quantitatively and systematically links expression Quantitative Trait Loci (eQTL) findings in C. elegans to gene–disease associations in man. WormQTLHD, available online at http://www.wormqtl-hd.org, is a user-friendly set of tools to reveal functionally coherent, evolutionary conserved gene networks. These can be used to predict novel gene-to-gene associations and the functions of genes underlying the disease of interest. We created a new database that links C. elegans eQTL data sets to human diseases (34 337 gene–disease associations from OMIM, DGA, GWAS Central and NHGRI GWAS Catalogue) based on overlapping sets of orthologous genes associated to phenotypes in these two species. We utilized QTL results, high-throughput molecular phenotypes, classical phenotypes and genotype data covering different developmental stages and environments from WormQTL database. All software is available as open source, built on MOLGENIS and xQTL workbench.
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Affiliation(s)
- K Joeri van der Velde
- Genomics Coordination Center, University of Groningen, University Medical Center Groningen, P.O. Box 30001, 9700 RB Groningen, The Netherlands, Groningen Bioinformatics Center, University of Groningen, P.O. Box 11103, 9700 CC Groningen, The Netherlands, Department of Genetics, University of Groningen, University Medical Center Groningen, P.O. Box 30001, 9700 RB Groningen, The Netherlands, Department of Bioinformatics, Hanze University of Applied Sciences, Groningen, Zernikeplein 11, 9747 AS, The Netherlands and Laboratory of Nematology, Wageningen University, 6708 PB Wageningen, The Netherlands
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Brinckman DD, Keppler-Noreuil KM, Blumhorst C, Biesecker LG, Sapp JC, Johnston JJ, Wiggs EA. Cognitive, sensory, and psychosocial characteristics in patients with Bardet-Biedl syndrome. Am J Med Genet A 2013; 161A:2964-71. [PMID: 24194441 DOI: 10.1002/ajmg.a.36245] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2012] [Accepted: 08/08/2013] [Indexed: 12/14/2022]
Abstract
Forty-two patients with a clinical diagnosis of Bardet-Biedl syndrome ages 2-61 years were given a neuropsychological test battery to evaluate cognitive, sensory, and behavioral functioning. These tests included the Wechsler scales of intelligence, Rey Auditory Verbal Learning Test, Boston Naming Test, D-KEFS Verbal Fluency Test, D-KEFS Color-Word Interference Test, D-KEFS Sorting Test, Wide Range Achievement Test: Math and Reading Subtests, Purdue Pegboard, The University of Pennsylvania Smell Identification Test, Social Communication Questionnaire, Social Responsiveness Scale, and Behavior Assessment System for Children, Second Edition, Parent Rating Scale. On the age appropriate Wechsler scale, the mean Verbal Comprehension was 81 (n = 36), Working Memory was 81 (n = 36), Perceptual Reasoning was 78 (n = 24) and Full Scale IQ was 75 (n = 26). Memory for a word list (Rey Auditory Verbal Learning Test) was in the average range with a mean of 89 (n = 19). Fine motor speed was slow on the Purdue with mean scores 3-4 standard deviations below norms. All subjects were microsmic on the University of Pennsylvania Smell Identification Test. Of these 42 patients, only 6 were able to complete all auditory and visual tests; 52% were unable to complete the visual tests due to impaired vision. A wide range of behavioral issues were endorsed on questionnaires given to parents. Most had social skill deficits but no pattern of either externalizing or internalizing problems. We identify a characteristic neuro-behavioral profile in our cohort comprised of reduced IQ, impaired fine-motor function, and decreased olfaction.
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Affiliation(s)
- Danielle D Brinckman
- Genetic Disease Research Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland
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Wang X, Wang H, Sun V, Tuan HF, Keser V, Wang K, Ren H, Lopez I, Zaneveld JE, Siddiqui S, Bowles S, Khan A, Salvo J, Jacobson SG, Iannaccone A, Wang F, Birch D, Heckenlively JR, Fishman GA, Traboulsi EI, Li Y, Wheaton D, Koenekoop RK, Chen R. Comprehensive molecular diagnosis of 179 Leber congenital amaurosis and juvenile retinitis pigmentosa patients by targeted next generation sequencing. J Med Genet 2013; 50:674-88. [PMID: 23847139 DOI: 10.1136/jmedgenet-2013-101558] [Citation(s) in RCA: 121] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
BACKGROUND Leber congenital amaurosis (LCA) and juvenile retinitis pigmentosa (RP) are inherited retinal diseases that cause early onset severe visual impairment. An accurate molecular diagnosis can refine the clinical diagnosis and allow gene specific treatments. METHODS We developed a capture panel that enriches the exonic DNA of 163 known retinal disease genes. Using this panel, we performed targeted next generation sequencing (NGS) for a large cohort of 179 unrelated and prescreened patients with the clinical diagnosis of LCA or juvenile RP. Systematic NGS data analysis, Sanger sequencing validation, and segregation analysis were utilised to identify the pathogenic mutations. Patients were revisited to examine the potential phenotypic ambiguity at the time of initial diagnosis. RESULTS Pathogenic mutations for 72 patients (40%) were identified, including 45 novel mutations. Of these 72 patients, 58 carried mutations in known LCA or juvenile RP genes and exhibited corresponding phenotypes, while 14 carried mutations in retinal disease genes that were not consistent with their initial clinical diagnosis. We revisited patients in the latter case and found that homozygous mutations in PRPH2 can cause LCA/juvenile RP. Guided by the molecular diagnosis, we reclassified the clinical diagnosis in two patients. CONCLUSIONS We have identified a novel gene and a large number of novel mutations that are associated with LCA/juvenile RP. Our results highlight the importance of molecular diagnosis as an integral part of clinical diagnosis.
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Affiliation(s)
- Xia Wang
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, Texas, USA
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50
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Wagner AH, Taylor KR, DeLuca AP, Casavant TL, Mullins RF, Stone EM, Scheetz TE, Braun TA. Prioritization of retinal disease genes: an integrative approach. Hum Mutat 2013; 34:853-9. [PMID: 23508994 DOI: 10.1002/humu.22317] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2012] [Accepted: 03/07/2013] [Indexed: 02/03/2023]
Abstract
The discovery of novel disease-associated variations in genes is often a daunting task in highly heterogeneous disease classes. We seek a generalizable algorithm that integrates multiple publicly available genomic data sources in a machine-learning model for the prioritization of candidates identified in patients with retinal disease. To approach this problem, we generate a set of feature vectors from publicly available microarray, RNA-seq, and ChIP-seq datasets of biological relevance to retinal disease, to observe patterns in gene expression specificity among tissues of the body and the eye, in addition to photoreceptor-specific signals by the CRX transcription factor. Using these features, we describe a novel algorithm, positive and unlabeled learning for prioritization (PULP). This article compares several popular supervised learning techniques as the regression function for PULP. The results demonstrate a highly significant enrichment for previously characterized disease genes using a logistic regression method. Finally, a comparison of PULP with the popular gene prioritization tool ENDEAVOUR shows superior prioritization of retinal disease genes from previous studies. The java source code, compiled binary, assembled feature vectors, and instructions are available online at https://github.com/ahwagner/PULP.
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Affiliation(s)
- Alex H Wagner
- Department of Biomedical Engineering, University of Iowa, Iowa City, Iowa 52242, USA.
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