1
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Tory K. The dominant findings of a recessive man: from Mendel's kid pea to kidney. Pediatr Nephrol 2024; 39:2049-2059. [PMID: 38051388 PMCID: PMC11147900 DOI: 10.1007/s00467-023-06238-9] [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: 08/21/2023] [Revised: 11/07/2023] [Accepted: 11/15/2023] [Indexed: 12/07/2023]
Abstract
The research of Mendel, born two centuries ago, still has many direct implications for our everyday clinical work. He introduced the terms "dominant" and "recessive" characters and determined their 3:1 ratio in the offspring of heterozygous "hybrid" plants. This distribution allowed calculation of the number of the phenotype-determining "elements," i.e., the alleles, and has been used ever since to prove the monogenic origin of a disorder. The Mendelian inheritance of monogenic kidney disorders is still of great help in distinguishing them from those with multifactorial origin in clinical practice. Inheritance of most monogenic kidney disorders fits to Mendel's observations: the equal contribution of the two parents and the complete penetrance or the direct correlation between the frequency of the recessive character and the degree of inbreeding. Nevertheless, beyond the truth of these basic concepts, several observations have expanded their genetic characteristics. The extreme genetic heterogeneity, the pleiotropy of the causal genes and the role of modifiers in ciliopathies, the digenic inheritance and parental imprinting in some tubulopathies, and the incomplete penetrance and eventual interallelic interactions in podocytopathies, reflect this expansion. For all these reasons, the transmission pattern in a natural setting may depend not only on the "character" but also on the causal gene and the variant. Mendel's passion for research combined with his modest personality and meticulous approach can still serve as an example in the work required to understand the non-Mendelian universe of genetics.
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Affiliation(s)
- Kálmán Tory
- MTA-SE Lendület Nephrogenetic Laboratory, Hungarian Academy of Sciences, Budapest, Hungary.
- Pediatric Center, MTA Center of Excellence, Semmelweis University, Budapest, Hungary.
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Ripolles-Garcia A, Murgiano L, Ziolkowska N, Marinho FP, Roszak K, Iffrig S, Aguirre GD, Miyadera K. Natural disease history of a canine model of oligogenic RPGRIP1-cone-rod dystrophy establishes variable effects of previously and newly mapped modifier loci. Hum Mol Genet 2023; 32:2139-2151. [PMID: 36951959 PMCID: PMC10281748 DOI: 10.1093/hmg/ddad046] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Revised: 02/23/2023] [Accepted: 03/21/2023] [Indexed: 03/24/2023] Open
Abstract
Canine RPGRIP1-cone-rod dystrophy (CRD), a model for human inherited retinal diseases (IRDs), was originally identified as autosomal recessive early-onset blindness. However, later studies revealed extensive phenotypic variability among RPGRIP1 mutants. This led to the identification of a homozygous MAP9 variant as a modifier associated with early-onset disease. Based on further phenotypic variation affecting cone photoreceptor function, we report mapping of L3 as an additional modifier locus, within a 4.1-Mb locus on canine chromosome 30. We establish the natural disease history of RPGRIP1-CRD based on up to 9-year long-term functional and structural retinal data from 58 dogs including 44 RPGRIP1 mutants grouped according to the modifier status. RPGRIP1 mutants affected by both MAP9 and L3 modifiers exhibited the most severe phenotypes with rapid disease progression. MAP9 alone was found to act as an overall accelerator of rod and cone diseases, while L3 had a cone-specific effect. Ultrastructural analysis of photoreceptors revealed varying degrees of rod and cone damage, while the connecting cilia appeared structurally preserved in all groups. We conclude that RPGRIP1-CRD is an oligogenic disease with at least three loci contributing to the pathogenesis. While the RPGRIP1 variant is required for developing the disease, MAP9 and L3 modifiers exacerbate the phenotype, individually and cumulatively. Oligogenic canine RPGRIP1-CRD illustrates the impact of multiple genetic modifiers on disease phenotype and thus has the potential to reveal new targets for broad-spectrum therapies for oligogenic or polygenic forms of human IRDs.
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Affiliation(s)
- Ana Ripolles-Garcia
- Division of Experimental Retinal Therapies, Department of Clinical Sciences & Advanced Medicine, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Leonardo Murgiano
- Division of Experimental Retinal Therapies, Department of Clinical Sciences & Advanced Medicine, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Natalia Ziolkowska
- Department of Histology and Embryology, Faculty of Veterinary Medicine, University of Warmia and Mazury, Olsztyn 10-719, Poland
| | - Felipe Pompeo Marinho
- Division of Experimental Retinal Therapies, Department of Clinical Sciences & Advanced Medicine, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Karolina Roszak
- Division of Experimental Retinal Therapies, Department of Clinical Sciences & Advanced Medicine, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Sommer Iffrig
- Division of Experimental Retinal Therapies, Department of Clinical Sciences & Advanced Medicine, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Gustavo D Aguirre
- Division of Experimental Retinal Therapies, Department of Clinical Sciences & Advanced Medicine, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Keiko Miyadera
- Division of Experimental Retinal Therapies, Department of Clinical Sciences & Advanced Medicine, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
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3
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Amorini M, Iapadre G, Mancuso A, Ceravolo I, Farello G, Scardamaglia A, Gramaglia S, Ceravolo A, Salpietro A, Cuppari C. An Overview of Genes Involved in the Pure Joubert Syndrome and in Joubert Syndrome-Related Disorders (JSRD). JOURNAL OF PEDIATRIC NEUROLOGY 2023. [DOI: 10.1055/s-0042-1760242] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
AbstractJoubert syndrome (JS) is a rare autosomal recessive disease characterized by a peculiar brain malformation, hypotonia, ataxia, developmental delay, abnormal eye movements, and neonatal breathing abnormalities. This picture is often associated with variable multiorgan involvement, mainly of the retina, kidneys and liver, defining a group of conditions termed syndrome and Joubert syndrome-related disorders (JSRD). Currently, more than 30 causative genes have been identified, involved in the development and stability of the primary cilium. Correlations genotype–phenotype are emerging between clinical presentations and mutations in JSRD genes, with implications in terms of molecular diagnosis, prenatal diagnosis, follow-up, and management of mutated patients.
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Affiliation(s)
- Maria Amorini
- Unit of Pediatric Emergency, Department of Human Pathology of the Adult and Developmental Age “Gaetano Barresi,” University of Messina, Messina, Italy
| | - Giulia Iapadre
- Department of Pediatrics, University of L'Aquila, L'Aquila, Italy
| | - Alessio Mancuso
- Unit of Pediatric Emergency, Department of Human Pathology of the Adult and Developmental Age “Gaetano Barresi,” University of Messina, Messina, Italy
| | - Ida Ceravolo
- Department of Clinical and Experimental Medicine, University of Messina, Messina, Italy
| | - Giovanni Farello
- Department of Life, Health and Environmental Sciences, Pediatric Clinic, Coppito (AQ), Italy
| | - Annarita Scardamaglia
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, University College London, London, United Kingdom
| | - Simone Gramaglia
- Unit of Pediatric Emergency, Department of Human Pathology of the Adult and Developmental Age “Gaetano Barresi,” University of Messina, Messina, Italy
| | | | | | - Caterina Cuppari
- Unit of Pediatric Emergency, Department of Human Pathology of the Adult and Developmental Age “Gaetano Barresi,” University of Messina, Messina, Italy
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4
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Vintschger E, Kraemer D, Joset P, Horn AHC, Rauch A, Sticht H, Bachmann-Gagescu R. Challenges for the implementation of next generation sequencing-based expanded carrier screening: Lessons learned from the ciliopathies. Eur J Hum Genet 2022:10.1038/s41431-022-01267-8. [PMID: 36550190 PMCID: PMC10400553 DOI: 10.1038/s41431-022-01267-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Revised: 11/18/2022] [Accepted: 12/09/2022] [Indexed: 12/24/2022] Open
Abstract
Next generation sequencing (NGS) can detect carrier status for rare recessive disorders, informing couples about their reproductive risk. The recent ACMG recommendations support offering NGS-based carrier screening (NGS-CS) in an ethnic and population-neutral manner for all genes that have a carrier frequency >1/200 (based on GnomAD). To evaluate current challenges for NGS-CS, we focused on the ciliopathies, a well-studied group of rare recessive disorders. We analyzed 118 ciliopathy genes by whole exome sequencing in ~400 healthy local individuals and ~1000 individuals from the UK1958-birth cohort. We found 20% of healthy individuals (1% of couples) to be carriers of reportable variants in a ciliopathy gene, while 50% (4% of couples) carry variants of uncertain significance (VUS). This large proportion of VUS is partly explained by the limited utility of the ACMG/AMP variant-interpretation criteria in healthy individuals, where phenotypic match or segregation criteria cannot be used. Most missense variants are thus classified as VUS and not reported, which reduces the negative predictive value of the screening test. We show how gene-specific variation patterns and structural protein information can help prioritize variants most likely to be disease-causing, for (future) functional assays. Even when considering only strictly pathogenic variants, the observed carrier frequency is substantially higher than expected based on estimated disease prevalence, challenging the 1/200 carrier frequency cut-off proposed for choice of genes to screen. Given the challenges linked to variant interpretation in healthy individuals and the uncertainties about true carrier frequencies, genetic counseling must clearly disclose these limitations of NGS-CS.
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Affiliation(s)
- Ella Vintschger
- Institute of Medical Genetics, University of Zurich, 8952, Schlieren, Switzerland
| | - Dennis Kraemer
- Institute of Medical Genetics, University of Zurich, 8952, Schlieren, Switzerland
| | - Pascal Joset
- Institute of Medical Genetics, University of Zurich, 8952, Schlieren, Switzerland.,Institute of Medical Genetics and Pathology, University Hospital Basel, 4031, Basel, Switzerland
| | - Anselm H C Horn
- Institute of Biochemistry, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 91054, Erlangen, Germany.,Praeclare Clinical Research Priority Program of the Medical Faculty, University of Zurich, Zurich, Switzerland
| | - Anita Rauch
- Institute of Medical Genetics, University of Zurich, 8952, Schlieren, Switzerland.,Praeclare Clinical Research Priority Program of the Medical Faculty, University of Zurich, Zurich, Switzerland
| | - Heinrich Sticht
- Institute of Biochemistry, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 91054, Erlangen, Germany
| | - Ruxandra Bachmann-Gagescu
- Institute of Medical Genetics, University of Zurich, 8952, Schlieren, Switzerland. .,Praeclare Clinical Research Priority Program of the Medical Faculty, University of Zurich, Zurich, Switzerland. .,Department of Molecular Life Sciences, University of Zurich, 8057, Zurich, Switzerland.
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Chang KJ, Wu HY, Yarmishyn AA, Li CY, Hsiao YJ, Chi YC, Lo TC, Dai HJ, Yang YC, Liu DH, Hwang DK, Chen SJ, Hsu CC, Kao CL. Genetics behind Cerebral Disease with Ocular Comorbidity: Finding Parallels between the Brain and Eye Molecular Pathology. Int J Mol Sci 2022; 23:ijms23179707. [PMID: 36077104 PMCID: PMC9456058 DOI: 10.3390/ijms23179707] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Revised: 08/18/2022] [Accepted: 08/22/2022] [Indexed: 11/30/2022] Open
Abstract
Cerebral visual impairments (CVIs) is an umbrella term that categorizes miscellaneous visual defects with parallel genetic brain disorders. While the manifestations of CVIs are diverse and ambiguous, molecular diagnostics stand out as a powerful approach for understanding pathomechanisms in CVIs. Nevertheless, the characterization of CVI disease cohorts has been fragmented and lacks integration. By revisiting the genome-wide and phenome-wide association studies (GWAS and PheWAS), we clustered a handful of renowned CVIs into five ontology groups, namely ciliopathies (Joubert syndrome, Bardet–Biedl syndrome, Alstrom syndrome), demyelination diseases (multiple sclerosis, Alexander disease, Pelizaeus–Merzbacher disease), transcriptional deregulation diseases (Mowat–Wilson disease, Pitt–Hopkins disease, Rett syndrome, Cockayne syndrome, X-linked alpha-thalassaemia mental retardation), compromised peroxisome disorders (Zellweger spectrum disorder, Refsum disease), and channelopathies (neuromyelitis optica spectrum disorder), and reviewed several mutation hotspots currently found to be associated with the CVIs. Moreover, we discussed the common manifestations in the brain and the eye, and collated animal study findings to discuss plausible gene editing strategies for future CVI correction.
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Affiliation(s)
- Kao-Jung Chang
- School of Medicine, National Yang Ming Chiao Tung University, Taipei 112304, Taiwan
- Department of Medical Research, Taipei Veterans General Hospital, Taipei 11217, Taiwan
- Institute of Clinical Medicine, National Yang Ming Chiao Tung University, Taipei 112304, Taiwan
| | - Hsin-Yu Wu
- School of Medicine, National Yang Ming Chiao Tung University, Taipei 112304, Taiwan
- Department of Medical Research, Taipei Veterans General Hospital, Taipei 11217, Taiwan
| | | | - Cheng-Yi Li
- School of Medicine, National Yang Ming Chiao Tung University, Taipei 112304, Taiwan
- Department of Medical Research, Taipei Veterans General Hospital, Taipei 11217, Taiwan
| | - Yu-Jer Hsiao
- School of Medicine, National Yang Ming Chiao Tung University, Taipei 112304, Taiwan
- Department of Medical Research, Taipei Veterans General Hospital, Taipei 11217, Taiwan
| | - Yi-Chun Chi
- Department of Ophthalmology, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung 80708, Taiwan
| | - Tzu-Chen Lo
- School of Medicine, National Yang Ming Chiao Tung University, Taipei 112304, Taiwan
- Department of Ophthalmology, Taipei Veterans General Hospital, Taipei 11217, Taiwan
| | - He-Jhen Dai
- School of Medicine, National Yang Ming Chiao Tung University, Taipei 112304, Taiwan
- Department of Medical Research, Taipei Veterans General Hospital, Taipei 11217, Taiwan
| | - Yi-Chiang Yang
- Department of Physical Medicine and Rehabilitation, Taipei Veterans General Hospital, Taipei 11217, Taiwan
| | - Ding-Hao Liu
- Institute of Clinical Medicine, National Yang Ming Chiao Tung University, Taipei 112304, Taiwan
- Department of Physical Medicine and Rehabilitation, Taipei Veterans General Hospital, Taipei 11217, Taiwan
| | - De-Kuang Hwang
- School of Medicine, National Yang Ming Chiao Tung University, Taipei 112304, Taiwan
- Institute of Clinical Medicine, National Yang Ming Chiao Tung University, Taipei 112304, Taiwan
- Department of Ophthalmology, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung 80708, Taiwan
| | - Shih-Jen Chen
- Department of Ophthalmology, Taipei Veterans General Hospital, Taipei 11217, Taiwan
| | - Chih-Chien Hsu
- School of Medicine, National Yang Ming Chiao Tung University, Taipei 112304, Taiwan
- Institute of Clinical Medicine, National Yang Ming Chiao Tung University, Taipei 112304, Taiwan
- Department of Ophthalmology, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung 80708, Taiwan
- Correspondence: (C.-C.H.); (C.-L.K.); Tel.: +886-2-287-573-25 (C.-C.H.); +886-2-287-573-63 (C.-L.K.)
| | - Chung-Lan Kao
- Institute of Clinical Medicine, National Yang Ming Chiao Tung University, Taipei 112304, Taiwan
- Department of Physical Medicine and Rehabilitation, Taipei Veterans General Hospital, Taipei 11217, Taiwan
- Department of Physical Medicine and Rehabilitation, School of Medicine, National Yang Ming Chiao Tung University, Taipei 112304, Taiwan
- Center for Intelligent Drug Systems and Smart Bio-Devices (IDS2B), National Yang Ming Chiao Tung University, Hsinchu 300093, Taiwan
- Correspondence: (C.-C.H.); (C.-L.K.); Tel.: +886-2-287-573-25 (C.-C.H.); +886-2-287-573-63 (C.-L.K.)
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6
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Rusterholz TDS, Hofmann C, Bachmann-Gagescu R. Insights Gained From Zebrafish Models for the Ciliopathy Joubert Syndrome. Front Genet 2022; 13:939527. [PMID: 35846153 PMCID: PMC9280682 DOI: 10.3389/fgene.2022.939527] [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: 05/09/2022] [Accepted: 05/26/2022] [Indexed: 12/04/2022] Open
Abstract
Cilia are quasi-ubiquitous microtubule-based sensory organelles, which play vital roles in signal transduction during development and cell homeostasis. Dysfunction of cilia leads to a group of Mendelian disorders called ciliopathies, divided into different diagnoses according to clinical phenotype constellation and genetic causes. Joubert syndrome (JBTS) is a prototypical ciliopathy defined by a diagnostic cerebellar and brain stem malformation termed the “Molar Tooth Sign” (MTS), in addition to which patients display variable combinations of typical ciliopathy phenotypes such as retinal dystrophy, fibrocystic renal disease, polydactyly or skeletal dystrophy. Like most ciliopathies, JBTS is genetically highly heterogeneous with ∼40 associated genes. Zebrafish are widely used to model ciliopathies given the high conservation of ciliary genes and the variety of specialized cilia types similar to humans. In this review, we compare different existing JBTS zebrafish models with each other and describe their contributions to our understanding of JBTS pathomechanism. We find that retinal dystrophy, which is the most investigated ciliopathy phenotype in zebrafish ciliopathy models, is caused by distinct mechanisms according to the affected gene. Beyond this, differences in phenotypes in other organs observed between different JBTS-mutant models suggest tissue-specific roles for proteins implicated in JBTS. Unfortunately, the lack of systematic assessment of ciliopathy phenotypes in the mutants described in the literature currently limits the conclusions that can be drawn from these comparisons. In the future, the numerous existing JBTS zebrafish models represent a valuable resource that can be leveraged in order to gain further insights into ciliary function, pathomechanisms underlying ciliopathy phenotypes and to develop treatment strategies using small molecules.
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Affiliation(s)
- Tamara D. S. Rusterholz
- Institute of Medical Genetics, University of Zurich, Schlieren, Switzerland
- Department of Molecular Life Sciences, University of Zurich, Zürich, Switzerland
| | - Claudia Hofmann
- Institute of Medical Genetics, University of Zurich, Schlieren, Switzerland
- Department of Molecular Life Sciences, University of Zurich, Zürich, Switzerland
| | - Ruxandra Bachmann-Gagescu
- Institute of Medical Genetics, University of Zurich, Schlieren, Switzerland
- Department of Molecular Life Sciences, University of Zurich, Zürich, Switzerland
- *Correspondence: Ruxandra Bachmann-Gagescu,
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Van De Weghe JC, Gomez A, Doherty D. The Joubert-Meckel-Nephronophthisis Spectrum of Ciliopathies. Annu Rev Genomics Hum Genet 2022; 23:301-329. [PMID: 35655331 DOI: 10.1146/annurev-genom-121321-093528] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The Joubert syndrome (JS), Meckel syndrome (MKS), and nephronophthisis (NPH) ciliopathy spectrum could be the poster child for advances and challenges in Mendelian human genetics over the past half century. Progress in understanding these conditions illustrates many core concepts of human genetics. The JS phenotype alone is caused by pathogenic variants in more than 40 genes; remarkably, all of the associated proteins function in and around the primary cilium. Primary cilia are near-ubiquitous, microtubule-based organelles that play crucial roles in development and homeostasis. Protruding from the cell, these cellular antennae sense diverse signals and mediate Hedgehog and other critical signaling pathways. Ciliary dysfunction causes many human conditions termed ciliopathies, which range from multiple congenital malformations to adult-onset single-organ failure. Research on the genetics of the JS-MKS-NPH spectrum has spurred extensive functional work exploring the broadly important role of primary cilia in health and disease. This functional work promises to illuminate the mechanisms underlying JS-MKS-NPH in humans, identify therapeutic targets across genetic causes, and generate future precision treatments. Expected final online publication date for the Annual Review of Genomics and Human Genetics, Volume 23 is October 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
| | - Arianna Gomez
- Department of Pediatrics, University of Washington, Seattle, Washington, USA; .,Molecular Medicine and Mechanisms of Disease Program, Department of Laboratory Medicine and Pathology, University of Washington, Seattle, Washington, USA;
| | - Dan Doherty
- Department of Pediatrics, University of Washington, Seattle, Washington, USA; .,Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, Washington, USA;
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Spahiu L, Behluli E, Grajçevci-Uka V, Liehr T, Temaj G. Joubert syndrome: Molecular basis and treatment. JOURNAL OF MOTHER AND CHILD 2022; 26:118-123. [PMID: 36803942 PMCID: PMC10032320 DOI: 10.34763/jmotherandchild.20222601.d-22-00034] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Accepted: 09/30/2022] [Indexed: 02/23/2023]
Abstract
Joubert syndrome (JS; MIM PS213300) is a rare genetic autosomal recessive disease characterized by cerebellar vermis hypoplasia, a distinctive malformation of the cerebellum and the so-called "molar tooth sign." Other characteristic features are hypotonia with lateral ataxia, intellectual disability/mental retardation, oculomotor apraxia, retinal dystrophy, abnormalities in the respiratory system, renal cysts, hepatic fibrosis, and skeletal changes. Such pleiotropic characteristics are typical of many disorders involving primary cilium aberrations, providing a significant overlap between JS and other ciliopathies such as nephronophthisis, Meckel syndrome, and Bardet-Biedl syndrome. This review will describe some characteristics of JS associated with changes in 35 genes, and will also address subtypes of JS, clinical diagnosis, and the future of therapeutic developments.
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Affiliation(s)
- Lidvana Spahiu
- Department of Pediatrics, University of Prishtina, Prishtina, Kosovo
| | - Emir Behluli
- Department of Pediatrics, University of Prishtina, Prishtina, Kosovo
| | | | - Thomas Liehr
- Institut für Humangenetik, Universitätsklinikum Jena, Friedrich Schiller Universität, Jena, Germany
| | - Gazmend Temaj
- Human Genetics, College UBT, Faculty of Pharmacy Prishtina, PrishtinaKosovo
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Gana S, Serpieri V, Valente EM. Genotype-phenotype correlates in Joubert syndrome: A review. AMERICAN JOURNAL OF MEDICAL GENETICS. PART C, SEMINARS IN MEDICAL GENETICS 2022; 190:72-88. [PMID: 35238134 PMCID: PMC9314610 DOI: 10.1002/ajmg.c.31963] [Citation(s) in RCA: 34] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Revised: 02/04/2022] [Accepted: 02/15/2022] [Indexed: 01/20/2023]
Abstract
Joubert syndrome (JS) is a genetically heterogeneous primary ciliopathy characterized by a pathognomonic cerebellar and brainstem malformation, the “molar tooth sign,” and variable organ involvement. Over 40 causative genes have been identified to date, explaining up to 94% of cases. To date, gene‐phenotype correlates have been delineated only for a handful of genes, directly translating into improved counseling and clinical care. For instance, JS individuals harboring pathogenic variants in TMEM67 have a significantly higher risk of liver fibrosis, while pathogenic variants in NPHP1, RPGRIP1L, and TMEM237 are frequently associated to JS with renal involvement, requiring a closer monitoring of liver parameters, or renal functioning. On the other hand, individuals with causal variants in the CEP290 or AHI1 need a closer surveillance for retinal dystrophy and, in case of CEP290, also for chronic kidney disease. These examples highlight how an accurate description of the range of clinical symptoms associated with defects in each causative gene, including the rare ones, would better address prognosis and help guiding a personalized management. This review proposes to address this issue by assessing the available literature, to confirm known, as well as to propose rare gene‐phenotype correlates in JS.
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Affiliation(s)
- Simone Gana
- Neurogenetics Research Center, IRCCS Mondino Foundation, Pavia, Italy
| | | | - Enza Maria Valente
- Neurogenetics Research Center, IRCCS Mondino Foundation, Pavia, Italy.,Department of Molecular Medicine, University of Pavia, Pavia, Italy
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10
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Pollara L, Sottile V, Valente EM. Patient-derived cellular models of primary ciliopathies. J Med Genet 2022; 59:517-527. [DOI: 10.1136/jmedgenet-2021-108315] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Accepted: 01/21/2022] [Indexed: 11/09/2022]
Abstract
Primary ciliopathies are rare inherited disorders caused by structural or functional defects in the primary cilium, a subcellular organelle present on the surface of most cells. Primary ciliopathies show considerable clinical and genetic heterogeneity, with disruption of over 100 genes causing the variable involvement of several organs, including the central nervous system, kidneys, retina, skeleton and liver. Pathogenic variants in one and the same gene may associate with a wide range of ciliopathy phenotypes, supporting the hypothesis that the individual genetic background, with potential additional variants in other ciliary genes, may contribute to a mutational load eventually determining the phenotypic manifestations of each patient. Functional studies in animal models have uncovered some of the pathophysiological mechanisms linking ciliary gene mutations to the observed phenotypes; yet, the lack of reliable human cell models has previously limited preclinical research and the development of new therapeutic strategies for primary ciliopathies. Recent technical advances in the generation of patient-derived two-dimensional (2D) and three-dimensional (3D) cellular models give a new spur to this research, allowing the study of pathomechanisms while maintaining the complexity of the genetic background of each patient, and enabling the development of innovative treatments to target specific pathways. This review provides an overview of available models for primary ciliopathies, from existing in vivo models to more recent patient-derived 2D and 3D in vitro models. We highlight the advantages of each model in understanding the functional basis of primary ciliopathies and facilitating novel regenerative medicine, gene therapy and drug testing strategies for these disorders.
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11
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Liu Q, Wang H, Zhao J, Liu Z, Sun D, Yuan A, Luo G, Wei W, Hou M. Four novel compound heterozygous mutations in C5orf42 gene in patients with pure and mild Joubert syndrome. Int J Dev Neurosci 2020; 80:455-463. [PMID: 32233090 DOI: 10.1002/jdn.10029] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Revised: 03/09/2020] [Accepted: 03/17/2020] [Indexed: 01/03/2023] Open
Abstract
Joubert syndrome (JS) is a rare clinically and genetically heterogeneous disease. Using whole or targeted exome sequencing, we identified four novel compound heterozygous mutations in chromosome 5 open reading frame 42 gene (C5orf42), including c.2876C>T (missense mutation) and c.3921+1G>A (splicing mutation), c.2292 -2delA (splicing mutation) and c.4067C>T (missense mutation), c.6997_6998insT (frameshift mutation) and c.8710C>T (nonsense mutation), c.3981G>C (nonsense mutation) and c.230 _233del (frameshift mutation), in four Chinese JS families. They were all inherited from their heterozygosis parents in the autosomal recessive inheritance mode. Pure JS clinical manifestations and mild neuroimaging findings were found in these patients. These verified the previous findings that C5orf42 mutations generally resulted in a purely neurological Joubert phenotype, and neuroimaging findings were mild in JS with C5orf42 mutations. Our report analyzed these C5orf42 mutations-associated phenotypes and neuroimaging findings in JS and updated the genetic variation spectrum of JS caused by C5orf42.These will help clinicians and geneticists reach a more accurate diagnosis for JS.
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Affiliation(s)
- Qiuyan Liu
- Department of Neurology and Rehabilitation, Qingdao Women and Children's Hospital, Qingdao University, Qingdao, P.R. China
| | - Haiqiao Wang
- Department of Traditional Chinese Medicine, School of Medicine, Ren Ji Hospital, Shanghai Jiaotong University, Shanghai, P.R. China
| | - Jianhui Zhao
- Department of Neurology and Rehabilitation, Qingdao Women and Children's Hospital, Qingdao University, Qingdao, P.R. China
| | - Zhicui Liu
- Department of Neurology and Rehabilitation, Qingdao Women and Children's Hospital, Qingdao University, Qingdao, P.R. China
| | - Dianrong Sun
- Department of Neurology and Rehabilitation, Qingdao Women and Children's Hospital, Qingdao University, Qingdao, P.R. China
| | - Aiyun Yuan
- Department of Neurology and Rehabilitation, Qingdao Women and Children's Hospital, Qingdao University, Qingdao, P.R. China
| | - Guangjin Luo
- Department of Neurology and Rehabilitation, Qingdao Women and Children's Hospital, Qingdao University, Qingdao, P.R. China
| | - Wei Wei
- Kangso Medical Inspection Co., Ltd, Beijing, P.R. China
| | - Mei Hou
- Department of Neurology and Rehabilitation, Qingdao Women and Children's Hospital, Qingdao University, Qingdao, P.R. China
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12
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Lalonde E, Rentas S, Lin F, Dulik MC, Skraban CM, Spinner NB. Genomic Diagnosis for Pediatric Disorders: Revolution and Evolution. Front Pediatr 2020; 8:373. [PMID: 32733828 PMCID: PMC7360789 DOI: 10.3389/fped.2020.00373] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Accepted: 06/02/2020] [Indexed: 12/14/2022] Open
Abstract
Powerful, recent advances in technologies to analyze the genome have had a profound impact on the practice of medical genetics, both in the laboratory and in the clinic. Increasing utilization of genome-wide testing such as chromosomal microarray analysis and exome sequencing have lead a shift toward a "genotype-first" approach. Numerous techniques are now available to diagnose a particular syndrome or phenotype, and while traditional techniques remain efficient tools in certain situations, higher-throughput technologies have become the de facto laboratory tool for diagnosis of most conditions. However, selecting the right assay or technology is challenging, and the wrong choice may lead to prolonged time to diagnosis, or even a missed diagnosis. In this review, we will discuss current core technologies for the diagnosis of classic genetic disorders to shed light on the benefits and disadvantages of these strategies, including diagnostic efficiency, variant interpretation, and secondary findings. Finally, we review upcoming technologies posed to impart further changes in the field of genetic diagnostics as we move toward "genome-first" practice.
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Affiliation(s)
- Emilie Lalonde
- Division of Genomic Diagnostics, Department of Pathology and Laboratory Medicine, School of Medicine, Children's Hospital of Philadelphia, University of Pennsylvania, Philadelphia, PA, United States
| | - Stefan Rentas
- Division of Genomic Diagnostics, Department of Pathology and Laboratory Medicine, School of Medicine, Children's Hospital of Philadelphia, University of Pennsylvania, Philadelphia, PA, United States
| | - Fumin Lin
- Division of Genomic Diagnostics, Department of Pathology and Laboratory Medicine, School of Medicine, Children's Hospital of Philadelphia, University of Pennsylvania, Philadelphia, PA, United States
| | - Matthew C. Dulik
- Division of Genomic Diagnostics, Department of Pathology and Laboratory Medicine, School of Medicine, Children's Hospital of Philadelphia, University of Pennsylvania, Philadelphia, PA, United States
| | - Cara M. Skraban
- Division of Human Genetics, Department of Pediatrics, School of Medicine, Children's Hospital of Philadelphia, University of Pennsylvania, Philadelphia, PA, United States
| | - Nancy B. Spinner
- Division of Genomic Diagnostics, Department of Pathology and Laboratory Medicine, School of Medicine, Children's Hospital of Philadelphia, University of Pennsylvania, Philadelphia, PA, United States
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13
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Shamseldin HE, Shaheen R, Ewida N, Bubshait DK, Alkuraya H, Almardawi E, Howaidi A, Sabr Y, Abdalla EM, Alfaifi AY, Alghamdi JM, Alsagheir A, Alfares A, Morsy H, Hussein MH, Al-Muhaizea MA, Shagrani M, Al Sabban E, Salih MA, Meriki N, Khan R, Almugbel M, Qari A, Tulba M, Mahnashi M, Alhazmi K, Alsalamah AK, Nowilaty SR, Alhashem A, Hashem M, Abdulwahab F, Ibrahim N, Alshidi T, AlObeid E, Alenazi MM, Alzaidan H, Rahbeeni Z, Al-Owain M, Sogaty S, Seidahmed MZ, Alkuraya FS. The morbid genome of ciliopathies: an update. Genet Med 2020; 22:1051-1060. [PMID: 32055034 DOI: 10.1038/s41436-020-0761-1] [Citation(s) in RCA: 61] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Revised: 01/28/2020] [Accepted: 01/29/2020] [Indexed: 11/09/2022] Open
Abstract
PURPOSE Ciliopathies are highly heterogeneous clinical disorders of the primary cilium. We aim to characterize a large cohort of ciliopathies phenotypically and molecularly. METHODS Detailed phenotypic and genomic analysis of patients with ciliopathies, and functional characterization of novel candidate genes. RESULTS In this study, we describe 125 families with ciliopathies and show that deleterious variants in previously reported genes, including cryptic splicing variants, account for 87% of cases. Additionally, we further support a number of previously reported candidate genes (BBIP1, MAPKBP1, PDE6D, and WDPCP), and propose nine novel candidate genes (CCDC67, CCDC96, CCDC172, CEP295, FAM166B, LRRC34, TMEM17, TTC6, and TTC23), three of which (LRRC34, TTC6, and TTC23) are supported by functional assays that we performed on available patient-derived fibroblasts. From a phenotypic perspective, we expand the phenomenon of allelism that characterizes ciliopathies by describing novel associations including WDR19-related Stargardt disease and SCLT1- and CEP164-related Bardet-Biedl syndrome. CONCLUSION In this cohort of phenotypically and molecularly characterized ciliopathies, we draw important lessons that inform the clinical management and the diagnostics of this class of disorders as well as their basic biology.
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Affiliation(s)
- Hanan E Shamseldin
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - Ranad Shaheen
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - Nour Ewida
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - Dalal K Bubshait
- Department of Pediatrics, College of Medicine, Imam Abdulrahman Bin Faisal University, Dammam, Saudi Arabia
| | - Hisham Alkuraya
- Department of Ophthalmology, Specialized Medical Center Hospital, Riyadh, Saudi Arabia
| | - Elham Almardawi
- Department of Obstetrics and Gynecology, Security Forces Hospital, Riyadh, Saudi Arabia
| | - Ali Howaidi
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - Yasser Sabr
- Deparment of Obstetrics and Gynecology, College of Medicine, King Saud University, Riyadh, Saudi Arabia
| | - Ebtesam M Abdalla
- Human Genetics Department, Medical Research Institute, Alexandria University, Alexandria, Egypt
| | - Abdullah Y Alfaifi
- Department of Pediatrics, Security Forces Hospital, Riyadh, Saudi Arabia
| | | | - Afaf Alsagheir
- Endocrinology Section, Department of Pediatrics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - Ahmed Alfares
- Department of Pediatrics, Prince Sultan Military Medical City, Riyadh, Saudi Arabia
| | - Heba Morsy
- Human Genetics Department, Medical Research Institute, Alexandria University, Alexandria, Egypt
| | - Maged H Hussein
- Nephrology Section, Department of Medicine, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - Mohammad A Al-Muhaizea
- Department of Neuroscience, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - Mohammad Shagrani
- Organ Transplant Center, King Faisal Specialist Hospital and Research Center, and College of Medicine, Alfaisal University, Riyadh, Saudi Arabia
| | - Essam Al Sabban
- Nephrology Section, Department of Pediatrics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - Mustafa A Salih
- Division of Pediatric Neurology, College of Medicine, King Saud University, Riyadh, Saudi Arabia
| | - Neama Meriki
- Department of Obstetrics and Gynecology, Security Forces Hospital, Riyadh, Saudi Arabia
| | - Rubina Khan
- Depatment of Obstetrics and Gynecology, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - Maisoon Almugbel
- Depatment of Obstetrics and Gynecology, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - Alya Qari
- Department of Medical Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - Maha Tulba
- Depatment of Obstetrics and Gynecology, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - Mohammed Mahnashi
- Divison of Genetics, Department of General Pediatrics, King Fahad Central Hospital, Jazan, Saudi Arabia
| | - Khalid Alhazmi
- Divison of Genetics, Department of General Pediatrics, King Fahad Central Hospital, Jazan, Saudi Arabia
| | - Abrar K Alsalamah
- Vitreoretinal Division, King Khaled Eye Specialist Hospital, Riyadh, Saudi Arabia
| | - Sawsan R Nowilaty
- Vitreoretinal Division, King Khaled Eye Specialist Hospital, Riyadh, Saudi Arabia
| | - Amal Alhashem
- Department of Pediatrics, Prince Sultan Military Medical City, Riyadh, Saudi Arabia.,Department of Anatomy and Cell Biology, College of Medicine, Alfaisal University, Riyadh, Saudi Arabia
| | - Mais Hashem
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - Firdous Abdulwahab
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - Niema Ibrahim
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - Tarfa Alshidi
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - Eman AlObeid
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - Mona M Alenazi
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - Hamad Alzaidan
- Department of Medical Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - Zuhair Rahbeeni
- Department of Medical Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - Mohammed Al-Owain
- Department of Medical Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - Sameera Sogaty
- Department of Pediatrics, King Fahad General Hospital, Jeddah, Saudi Arabia
| | | | - Fowzan S Alkuraya
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia. .,Department of Pediatrics, Prince Sultan Military Medical City, Riyadh, Saudi Arabia. .,Department of Anatomy and Cell Biology, College of Medicine, Alfaisal University, Riyadh, Saudi Arabia.
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14
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Bachmann-Gagescu R, Dempsey JC, Bulgheroni S, Chen ML, D'Arrigo S, Glass IA, Heller T, Héon E, Hildebrandt F, Joshi N, Knutzen D, Kroes HY, Mack SH, Nuovo S, Parisi MA, Snow J, Summers AC, Symons JM, Zein WM, Boltshauser E, Sayer JA, Gunay-Aygun M, Valente EM, Doherty D. Healthcare recommendations for Joubert syndrome. Am J Med Genet A 2019; 182:229-249. [PMID: 31710777 DOI: 10.1002/ajmg.a.61399] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Revised: 10/02/2019] [Accepted: 10/09/2019] [Indexed: 12/19/2022]
Abstract
Joubert syndrome (JS) is a recessive neurodevelopmental disorder defined by a characteristic cerebellar and brainstem malformation recognizable on axial brain magnetic resonance imaging as the "Molar Tooth Sign". Although defined by the neurological features, JS is associated with clinical features affecting many other organ systems, particularly progressive involvement of the retina, kidney, and liver. JS is a rare condition; therefore, many affected individuals may not have easy access to subspecialty providers familiar with JS (e.g., geneticists, neurologists, developmental pediatricians, ophthalmologists, nephrologists, hepatologists, psychiatrists, therapists, and educators). Expert recommendations can enable practitioners of all types to provide quality care to individuals with JS and know when to refer for subspecialty care. This need will only increase as precision treatments targeting specific genetic causes of JS emerge. The goal of these recommendations is to provide a resource for general practitioners, subspecialists, and families to maximize the health of individuals with JS throughout the lifespan.
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Affiliation(s)
- Ruxandra Bachmann-Gagescu
- Institute of Molecular Life Sciences, University of Zurich, Zurich, Switzerland.,Institute of Medical Genetics, University of Zurich, Schlieren, Switzerland
| | - Jennifer C Dempsey
- Department of Pediatrics, University of Washington School of Medicine, Seattle, Washington
| | - Sara Bulgheroni
- Developmental Neurology Division, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Maida L Chen
- Department of Pediatrics, University of Washington School of Medicine, Seattle, Washington.,Division of Pulmonary and Sleep Medicine, Seattle Children's Hospital, Seattle, Washington
| | - Stefano D'Arrigo
- Developmental Neurology Division, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Ian A Glass
- Department of Pediatrics, University of Washington School of Medicine, Seattle, Washington
| | - Theo Heller
- Liver Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland
| | - Elise Héon
- Department of Surgery, Hospital for Sick Children, Toronto, Ontario, Canada.,Department of Ophthalmology and Vision Science, University of Toronto, Toronto, Ontario, Canada
| | - Friedhelm Hildebrandt
- Department of Pediatrics, Harvard Medical School, Boston, Massachusetts.,Division of Nephrology, Boston Children's Hospital, Boston, Massachusetts
| | - Nirmal Joshi
- Department of Anesthesia, Deaconess Hospital, Evansville, Indiana.,Anesthesia Dynamics, LLC, Evansville, Indiana
| | - Dana Knutzen
- Department of Obstetrics and Gynecology, Baylor College of Medicine, Houston, Texas.,The Children's Hospital of San Antonio, San Antonio, Texas
| | - Hester Y Kroes
- Department of Medical Genetics, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Stephen H Mack
- Joubert Syndrome and Related Disorders Foundation, Petaluma, California
| | - Sara Nuovo
- Neurogenetics Lab, IRCCS Santa Lucia Foundation, Rome, Italy.,Department of Medicine and Surgery, University of Salerno, Salerno, Italy
| | - Melissa A Parisi
- Intellectual and Developmental Disabilities Branch, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland
| | - Joseph Snow
- Office of the Clinical Director, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland
| | - Angela C Summers
- Office of the Clinical Director, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland.,Department of Psychology, Fordham University, Bronx, New York
| | - Jordan M Symons
- Department of Pediatrics, University of Washington School of Medicine, Seattle, Washington.,Division of Nephrology, Seattle Children's Hospital, Seattle, Washington
| | - Wadih M Zein
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, Maryland
| | - Eugen Boltshauser
- Department of Pediatric Neurology (emeritus), Children's University Hospital, Zürich, Switzerland
| | - John A Sayer
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK.,Renal Services, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, UK.,NIHR Newcastle Biomedical Research Centre, Newcastle upon Tyne, UK
| | - Meral Gunay-Aygun
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland.,Department of Pediatrics and McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Enza Maria Valente
- Neurogenetics Lab, IRCCS Santa Lucia Foundation, Rome, Italy.,Department of Molecular Medicine, University of Pavia, Pavia, Italy
| | - Dan Doherty
- Department of Pediatrics, University of Washington School of Medicine, Seattle, Washington.,Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, Washington
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15
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Ołdak M, Lechowicz U, Pollak A, Oziębło D, Skarżyński H. Overinterpretation of high throughput sequencing data in medical genetics: first evidence against TMPRSS3/GJB2 digenic inheritance of hearing loss. J Transl Med 2019; 17:269. [PMID: 31412945 PMCID: PMC6694500 DOI: 10.1186/s12967-019-2018-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Accepted: 08/06/2019] [Indexed: 11/15/2022] Open
Abstract
Background Hearing loss (HL) is the most common disability of human senses characterized by a great allelic heterogeneity. GJB2 and TMPRSS3 are two well-known HL genes typically underlying its monogenic form. Recently, TMPRSS3/GJB2 digenic inheritance has been proposed. As results of genetic testing can be easily overinterpreted, we aimed to verify the hypothesis. Methods From genetic database of HL patients with at least one TMPRSS3 pathogenic variants we have selected individuals with additional GJB2 pathogenic variants. All of the available family members were recruited for the study. Segregation analysis of the respective TMPRSS3 and GJB2 pathogenic variants was performed within the families. Results The strategy has allowed to identify four individuals who were double heterozygous for known pathogenic TMPRSS3 and GJB2 variants. Two individuals from different families had GJB2 c.35delG and TMPRSS3 c.208delC and in two other individuals from one family GJB2 c.35delG together with TMPRSS3 c.1343T>C variants were found. None of these subjects has ever reported hearing problems and their hearing status was normal. Conclusions Our data provide evidence against TMPRSS3/GJB2 digenic inheritance of HL. As high throughput sequencing is increasingly used for genetic testing, particular caution should be taken to provide the patients with accurate genetic counseling.
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Affiliation(s)
- Monika Ołdak
- Department of Genetics, World Hearing Center, Institute of Physiology and Pathology of Hearing, M. Mochnackiego 10, 02-042, Warsaw, Poland.
| | - Urszula Lechowicz
- Department of Genetics, World Hearing Center, Institute of Physiology and Pathology of Hearing, M. Mochnackiego 10, 02-042, Warsaw, Poland
| | - Agnieszka Pollak
- Department of Genetics, World Hearing Center, Institute of Physiology and Pathology of Hearing, M. Mochnackiego 10, 02-042, Warsaw, Poland
| | - Dominika Oziębło
- Department of Genetics, World Hearing Center, Institute of Physiology and Pathology of Hearing, M. Mochnackiego 10, 02-042, Warsaw, Poland.,Postgraduate School of Molecular Medicine, Medical University of Warsaw, Warsaw, Poland
| | - Henryk Skarżyński
- Oto-Rhino-Laryngology Surgery Clinic, Institute of Physiology and Pathology of Hearing, M. Mochnackiego 10, 02-042, Warsaw, Poland
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16
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Niederlova V, Modrak M, Tsyklauri O, Huranova M, Stepanek O. Meta-analysis of genotype-phenotype associations in Bardet-Biedl syndrome uncovers differences among causative genes. Hum Mutat 2019; 40:2068-2087. [PMID: 31283077 DOI: 10.1002/humu.23862] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Revised: 06/17/2019] [Accepted: 07/03/2019] [Indexed: 12/16/2022]
Abstract
Bardet-Biedl syndrome (BBS) is a recessive genetic disease causing multiple organ anomalies. Most patients carry mutations in genes encoding for the subunits of the BBSome, an octameric ciliary transport complex, or accessory proteins involved in the BBSome assembly or function. BBS proteins have been extensively studied using in vitro, cellular, and animal models. However, the molecular functions of particular BBS proteins and the etiology of the BBS symptoms are still largely elusive. In this study, we applied a meta-analysis approach to study the genotype-phenotype association in humans using our database of all reported BBS patients. The analysis revealed that the identity of the causative gene and the character of the mutation partially predict the clinical outcome of the disease. Besides their potential use for clinical prognosis, our analysis revealed functional differences of particular BBS genes in humans. Core BBSome subunits BBS2, BBS7, and BBS9 manifest as more critical for the function and development of kidneys than peripheral subunits BBS1, BBS4, and BBS8/TTC8, suggesting that incomplete BBSome retains residual function at least in the kidney.
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Affiliation(s)
- Veronika Niederlova
- Laboratory of Adaptive Immunity, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czech Republic
| | - Martin Modrak
- Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Oksana Tsyklauri
- Laboratory of Adaptive Immunity, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czech Republic
| | - Martina Huranova
- Laboratory of Adaptive Immunity, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czech Republic
| | - Ondrej Stepanek
- Laboratory of Adaptive Immunity, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czech Republic
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17
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Parisi MA. The molecular genetics of Joubert syndrome and related ciliopathies: The challenges of genetic and phenotypic heterogeneity. ACTA ACUST UNITED AC 2019; 4:25-49. [PMID: 31763177 PMCID: PMC6864416 DOI: 10.3233/trd-190041] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Joubert syndrome (JS; MIM PS213300) is a rare, typically autosomal recessive disorder characterized by cerebellar vermis hypoplasia and a distinctive malformation of the cerebellum and brainstem identified as the “molar tooth sign” on brain MRI. Other universal features include hypotonia with later ataxia and intellectual disability/developmental delay, with additional features consisting of oculomotor apraxia and abnormal respiratory pattern. Notably, other, more variable features include renal cystic disease, typically nephronophthisis, retinal dystrophy, and congenital hepatic fibrosis; skeletal changes such as polydactyly and findings consistent with short-rib skeletal dysplasias are also seen in many subjects. These pleiotropic features are typical of a number of disorders of the primary cilium, and make the identification of causal genes challenging given the significant overlap between JS and other ciliopathy conditions such as nephronophthisis and Meckel, Bardet-Biedl, and COACH syndromes. This review will describe the features of JS, characterize the 35 known genes associated with the condition, and describe some of the genetic conundrums of JS, such as the heterogeneity of founder effects, lack of genotype-phenotype correlations, and role of genetic modifiers. Finally, aspects of JS and related ciliopathies that may pave the way for development of therapeutic interventions, including gene therapy, will be described.
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Affiliation(s)
- Melissa A Parisi
- Chief, Intellectual & Developmental Disabilities Branch, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health (NIH), Bethesda, MD, USA
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18
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The photoreceptor cilium and its diseases. Curr Opin Genet Dev 2019; 56:22-33. [DOI: 10.1016/j.gde.2019.05.004] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Revised: 04/21/2019] [Accepted: 05/11/2019] [Indexed: 12/26/2022]
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19
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Overlap of polymicrogyria, hydrocephalus, and Joubert syndrome in a family with novel truncating mutations in ADGRG1/GPR56 and KIAA0556. Neurogenetics 2019; 20:91-98. [PMID: 30982090 DOI: 10.1007/s10048-019-00577-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Accepted: 02/15/2019] [Indexed: 12/18/2022]
Abstract
Genetic mutations associated with brain malformations can lead to a spectrum of severity and it is often difficult to determine whether there are additional pathogenic variants contributing to the phenotype. Here, we present a family affected by a severe brain malformation including bilateral polymicrogyria, hydrocephalus, patchy white matter signal changes, and cerebellar and pontine hypoplasia with elongated cerebellar peduncles leading to the molar tooth sign. While the malformation is reminiscent of bilateral frontoparietal polymicrogyria (BFPP), the phenotype is more severe than previously reported and also includes features of Joubert syndrome (JBTS). Via exome sequencing, we identified homozygous truncating mutations in both ADGRG1/GPR56 and KIAA0556, which are known to cause BFPP and mild brain-specific JBTS, respectively. This study shows how two independent mutations can interact leading to complex brain malformations.
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20
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Mégarbané A, Hmaimess G, Bizzari S, El-Bazzal L, Al-Ali MT, Stora S, Delague V, El-Hayek S. A novel PDE6D mutation in a patient with Joubert syndrome type 22 (JBTS22). Eur J Med Genet 2018; 62:103576. [PMID: 30423442 DOI: 10.1016/j.ejmg.2018.11.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Revised: 10/02/2018] [Accepted: 11/09/2018] [Indexed: 10/27/2022]
Abstract
Joubert syndrome (JS) is an autosomal or X-linked recessive syndrome principally characterized by hypotonia, ataxia, cognitive impairment, and a specific finding on brain imaging called a "molar tooth sign" (MTS), which can be isolated or in conjunction with variable organ involvement. The genetic basis of JS is heterogeneous, with over 35 ciliary genes being implicated in its pathogenesis. However, some of these genes (such as PDE6D) have been associated to JS only in single families, seeking confirmation. Here we report a boy, born to first cousin parents, presenting with developmental delay, hypotonia, microcephaly, post axial polydactyly, oculomotor apraxia, and MTS. Whole exome sequencing revealed the presence of a novel homozygous truncating variant in the PDE6D gene: NM_002601.3:c.367_368insG [p.(Leu123Cysfs*13)]. The variant was confirmed by Sanger sequencing and found at the heterozygous state in both parents. A review of the literature pertaining to the role of PDE6D in JS is discussed.
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Affiliation(s)
| | | | - Sami Bizzari
- Centre for Arab Genomic Studies, Dubai, United Arab Emirates
| | - Lara El-Bazzal
- Aix Marseille Univ, Inserm, MMG, U 1251, Marseille, France
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21
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Srivastava S, Molinari E, Raman S, Sayer JA. Many Genes-One Disease? Genetics of Nephronophthisis (NPHP) and NPHP-Associated Disorders. Front Pediatr 2017; 5:287. [PMID: 29379777 PMCID: PMC5770800 DOI: 10.3389/fped.2017.00287] [Citation(s) in RCA: 80] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Accepted: 12/14/2017] [Indexed: 12/13/2022] Open
Abstract
Nephronophthisis (NPHP) is a renal ciliopathy and an autosomal recessive cause of cystic kidney disease, renal fibrosis, and end-stage renal failure, affecting children and young adults. Molecular genetic studies have identified more than 20 genes underlying this disorder, whose protein products are all related to cilia, centrosome, or mitotic spindle function. In around 15% of cases, there are additional features of a ciliopathy syndrome, including retinal defects, liver fibrosis, skeletal abnormalities, and brain developmental disorders. Alongside, gene identification has arisen molecular mechanistic insights into the disease pathogenesis. The genetic causes of NPHP are discussed in terms of how they help us to define treatable disease pathways including the cyclic adenosine monophosphate pathway, the mTOR pathway, Hedgehog signaling pathways, and DNA damage response pathways. While the underlying pathology of the many types of NPHP remains similar, the defined disease mechanisms are diverse, and a personalized medicine approach for therapy in NPHP patients is likely to be required.
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Affiliation(s)
- Shalabh Srivastava
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, United Kingdom.,Renal Unit, City Hospitals Sunderland and South Tyneside NHS Foundation Trust, Sunderland, United Kingdom
| | - Elisa Molinari
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Shreya Raman
- Department of Histopathology, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, United Kingdom
| | - John A Sayer
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, United Kingdom.,Renal Services, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, United Kingdom
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Hartill V, Szymanska K, Sharif SM, Wheway G, Johnson CA. Meckel-Gruber Syndrome: An Update on Diagnosis, Clinical Management, and Research Advances. Front Pediatr 2017; 5:244. [PMID: 29209597 PMCID: PMC5701918 DOI: 10.3389/fped.2017.00244] [Citation(s) in RCA: 87] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Accepted: 11/02/2017] [Indexed: 11/13/2022] Open
Abstract
Meckel-Gruber syndrome (MKS) is a lethal autosomal recessive congenital anomaly syndrome caused by mutations in genes encoding proteins that are structural or functional components of the primary cilium. Conditions that are caused by mutations in ciliary genes are collectively termed the ciliopathies, and MKS represents the most severe condition in this group of disorders. The primary cilium is a microtubule-based organelle, projecting from the apical surface of vertebrate cells. It acts as an "antenna" that receives and transduces chemosensory and mechanosensory signals, but also regulates diverse signaling pathways, such as Wnt and Shh, that have important roles during embryonic development. Most MKS proteins localize to a distinct ciliary compartment called the transition zone (TZ) that regulates the trafficking of cargo proteins or lipids. In this review, we provide an up-to-date summary of MKS clinical features, molecular genetics, and clinical diagnosis. MKS has a highly variable phenotype, extreme genetic heterogeneity, and displays allelism with other related ciliopathies such as Joubert syndrome, presenting significant challenges to diagnosis. Recent advances in genetic technology, with the widespread use of multi-gene panels for molecular testing, have significantly improved diagnosis, genetic counseling, and the clinical management of MKS families. These include the description of some limited genotype-phenotype correlations. We discuss recent insights into the molecular basis of disease in MKS, since the functions of some of the relevant ciliary proteins have now been determined. A common molecular etiology appears to be disruption of ciliary TZ structure and function, affecting essential developmental signaling and the regulation of secondary messengers.
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Affiliation(s)
- Verity Hartill
- Department of Clinical Genetics, Yorkshire Regional Genetics Service, Leeds Teaching Hospitals NHS Trust, Leeds, United Kingdom.,Leeds Institute of Biomedical and Clinical Sciences, University of Leeds, Leeds, United Kingdom
| | - Katarzyna Szymanska
- Leeds Institute of Biomedical and Clinical Sciences, University of Leeds, Leeds, United Kingdom
| | - Saghira Malik Sharif
- Department of Clinical Genetics, Yorkshire Regional Genetics Service, Leeds Teaching Hospitals NHS Trust, Leeds, United Kingdom
| | - Gabrielle Wheway
- Faculty of Health and Applied Sciences, Department of Applied Sciences, UWE Bristol, Bristol, United Kingdom
| | - Colin A Johnson
- Leeds Institute of Biomedical and Clinical Sciences, University of Leeds, Leeds, United Kingdom
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