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Lin T, Ma Y, Zhou D, Sun L, Chen K, Xiang Y, Tong K, Jia C, Jiang K, Liu D, Huang G. Case Report: Preimplantation Genetic Testing for Meckel Syndrome Induced by Novel Compound Heterozygous Mutations of MKS1. Front Genet 2022; 13:843931. [PMID: 35360848 PMCID: PMC8963843 DOI: 10.3389/fgene.2022.843931] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2021] [Accepted: 02/02/2022] [Indexed: 11/13/2022] Open
Abstract
Meckel syndrome (MKS), also known as the Meckel–Gruber syndrome, is a severe pleiotropic autosomal recessive developmental disorder caused by dysfunction of the primary cilia during early embryogenesis. The diagnostic criteria are based on clinical variability and genetic heterogeneity. Mutations in the MKS1 gene constitute approximately 7% of all MKS cases. Herein, we present a non-consanguineous couple with three abnormal pregnancies as the fetuses showed MKS-related phenotypes of the central nervous system malformation and postaxial polydactyly. Whole-exome sequencing identified two novel heterozygous mutations of MKS1: c.350C>A and c.1408-14A>G. The nonsense mutation c.350C>A produced a premature stop codon and induced the truncation of the MKS1 protein (p.S117*). Reverse-transcription polymerase chain reaction (RT-PCR) showed that c.1408-14A>G skipped exon 16 and encoded the mutant MKS1 p.E471Lfs*92. Functional studies showed that these two mutations disrupted the B9–C2 domain of the MKS1 protein and attenuated the interactions with B9D2, the essential component of the ciliary transition zone. The couple finally got a healthy baby through preimplantation genetic testing for monogenic disorder (PGT-M) with haplotype linkage analysis. Thus, this study expanded the mutation spectrum of MKS1 and elucidated the genetic heterogeneity of MKS1 in clinical cases.
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Affiliation(s)
- Tingting Lin
- Chongqing Key Laboratory of Human Embryo Engineering, Chongqing, China
- Chongqing Clinical Research Center for Reproductive Medicine, Chongqing, China
- Reproductive and Genetic Institute, Chongqing Health Center for Women and Children, Chongqing, China
| | - Yongyi Ma
- The Southwest Hospital of Army Medical University, Chongqing, China
| | - Danni Zhou
- Chongqing Key Laboratory of Human Embryo Engineering, Chongqing, China
- Chongqing Clinical Research Center for Reproductive Medicine, Chongqing, China
- Reproductive and Genetic Institute, Chongqing Health Center for Women and Children, Chongqing, China
| | - Liwei Sun
- Chongqing Key Laboratory of Human Embryo Engineering, Chongqing, China
- Chongqing Clinical Research Center for Reproductive Medicine, Chongqing, China
- Reproductive and Genetic Institute, Chongqing Health Center for Women and Children, Chongqing, China
| | - Ke Chen
- Chongqing Key Laboratory of Human Embryo Engineering, Chongqing, China
- Chongqing Clinical Research Center for Reproductive Medicine, Chongqing, China
- Reproductive and Genetic Institute, Chongqing Health Center for Women and Children, Chongqing, China
| | - Yezhou Xiang
- Chongqing Key Laboratory of Human Embryo Engineering, Chongqing, China
- Chongqing Clinical Research Center for Reproductive Medicine, Chongqing, China
- Reproductive and Genetic Institute, Chongqing Health Center for Women and Children, Chongqing, China
| | - Keya Tong
- Chongqing Key Laboratory of Human Embryo Engineering, Chongqing, China
- Chongqing Clinical Research Center for Reproductive Medicine, Chongqing, China
- Reproductive and Genetic Institute, Chongqing Health Center for Women and Children, Chongqing, China
| | - Chaoli Jia
- Chongqing Key Laboratory of Human Embryo Engineering, Chongqing, China
- Chongqing Clinical Research Center for Reproductive Medicine, Chongqing, China
- Reproductive and Genetic Institute, Chongqing Health Center for Women and Children, Chongqing, China
| | - Kean Jiang
- Chongqing Key Laboratory of Human Embryo Engineering, Chongqing, China
- Chongqing Clinical Research Center for Reproductive Medicine, Chongqing, China
- Reproductive and Genetic Institute, Chongqing Health Center for Women and Children, Chongqing, China
| | - Dongyun Liu
- Chongqing Key Laboratory of Human Embryo Engineering, Chongqing, China
- Chongqing Clinical Research Center for Reproductive Medicine, Chongqing, China
- Reproductive and Genetic Institute, Chongqing Health Center for Women and Children, Chongqing, China
- *Correspondence: Dongyun Liu, ; Guoning Huang,
| | - Guoning Huang
- Chongqing Key Laboratory of Human Embryo Engineering, Chongqing, China
- Chongqing Clinical Research Center for Reproductive Medicine, Chongqing, China
- Reproductive and Genetic Institute, Chongqing Health Center for Women and Children, Chongqing, China
- *Correspondence: Dongyun Liu, ; Guoning Huang,
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Paschereit F, Schindelmann KH, Hummel M, Schneider J, Stoltenburg-Didinger G, Kaindl AM. Cerebral Abnormalities in Spina Bifida: A Neuropathological Study. Pediatr Dev Pathol 2022; 25:107-123. [PMID: 34614376 PMCID: PMC9109215 DOI: 10.1177/10935266211040500] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
INTRODUCTION Spina bifida (SB) is the most common neural tube defect in humans. Here, we analyzed systematically the neuropathological findings of the brain in SB cases. METHODS 79 cases with SB aperta (SBA) and 6 cases with SB occulta (SBO) autopsied at the Charité Neuropathology from 1974 to 2000 were re-evaluated retrospectively. For this, case files and spinal cord as well as brain sections were studied. RESULTS While no brain malformations were detected in SBO cases, 95% of SBA cases had brain malformations. Main brain anomalies identified were hydrocephalus (71%), Chiari II malformation (36%), heterotopia (34%), other cerebellar anomalies (36%), gyrification defects (33%), and ependymal denudation (29%). Hydrocephalus was observed as early as gestational week 17 and was highly associated to Chiari II and ependymal denudation. In 55% SBA was accompanied by further anomalies not primarily affecting the CNS. CONCLUSION We confirm using neuropathologic methods brain malformations in most SBA but none in SBO cases. In addition to our previous radiologic study, we now demonstrate the high prevalence of cerebellar malformations and cerebral heterotopias in SBA. The early detection of hydrocephalus and Chiari II malformation in fetuses raises the question whether these arise parallel rather than in strict temporal sequence.
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Affiliation(s)
- Fabienne Paschereit
- Institute of Cell Biology and Neurobiology, Charité—Universitätsmedizin Berlin, Berlin, Germany,Department of Pediatric Neurology, Charité—Universitätsmedizin Berlin, Berlin, Germany
| | - Kim Hannah Schindelmann
- Institute of Cell Biology and Neurobiology, Charité—Universitätsmedizin Berlin, Berlin, Germany,Department of Pediatric Neurology, Charité—Universitätsmedizin Berlin, Berlin, Germany
| | - Michael Hummel
- Institute of Pathology, Charité—Universitätsmedizin Berlin, Berlin, Germany
| | - Joanna Schneider
- Department of Pediatric Neurology, Charité—Universitätsmedizin Berlin, Berlin, Germany,Center for Chronically Sick Children (Sozialpädiatrisches Zentrum, SPZ), Charité—Universitätsmedizin Berlin, Berlin, Germany
| | | | - Angela M Kaindl
- Institute of Cell Biology and Neurobiology, Charité—Universitätsmedizin Berlin, Berlin, Germany,Department of Pediatric Neurology, Charité—Universitätsmedizin Berlin, Berlin, Germany,Center for Chronically Sick Children (Sozialpädiatrisches Zentrum, SPZ), Charité—Universitätsmedizin Berlin, Berlin, Germany,Angela M Kaindl, Department of Pediatric Neurology, Charité—Universitätsmedizin Berlin, Augustenburger Platz 1, 13353 Berlin, Germany.
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Gana S, Serpieri V, Valente EM. Genotype-phenotype correlates in Joubert syndrome: A review. Am J Med Genet C Semin Med Genet 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] [What about the content of this article? (0)] [Affiliation(s)] [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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Brunetti-Pierri R, Karali M, Testa F, Cappuccio G, Onore ME, Romano F, De Rosa G, Tedeschi E, Brunetti-Pierri N, Banfi S, Simonelli F. Mild Clinical Presentation of Joubert Syndrome in a Male Adult Carrying Biallelic MKS1 Truncating Variants. Diagnostics (Basel) 2021; 11:diagnostics11071218. [PMID: 34359301 PMCID: PMC8303764 DOI: 10.3390/diagnostics11071218] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Revised: 07/01/2021] [Accepted: 07/01/2021] [Indexed: 11/16/2022] Open
Abstract
Pathogenic variants in the MKS1 gene are responsible for a ciliopathy with a wide spectrum of clinical manifestations ranging from Meckel and Joubert syndrome (JBTS) to Bardet-Biedl syndrome, and involving the central nervous system, liver, kidney, skeleton, and retina. We report a 39-year-old male individual presenting with isolated Retinitis Pigmentosa (RP), as assessed by full ophthalmological evaluation including Best-Corrected Visual Acuity measurements, fundus examination, Goldmann Visual Field test, and full-field Electroretinography. A clinical exome identified biallelic nonsense variants in MKS1 that prompted post-genotyping investigations for systemic abnormalities of ciliopathy. Brain magnetic resonance imaging revealed malformations of the posterior cranial fossa with the ‘molar tooth sign’ and cerebellar folia dysplasia, which are both distinctive features of JBTS. No other organ or skeletal abnormalities were detected. This case illustrates the power of clinical exome for the identification of the mildest forms of a disease spectrum, such as a mild JBTS with RP in the presented case of an individual carrying biallelic truncating variants in MKS1.
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Affiliation(s)
- Raffaella Brunetti-Pierri
- Eye Clinic, Multidisciplinary Department of Medical, Surgical and Dental Sciences, Università degli Studi della Campania ‘Luigi Vanvitelli’, Via Pansini 5, 80131 Naples, Italy; (R.B.-P.); (M.K.); (G.D.R.); (F.S.)
| | - Marianthi Karali
- Eye Clinic, Multidisciplinary Department of Medical, Surgical and Dental Sciences, Università degli Studi della Campania ‘Luigi Vanvitelli’, Via Pansini 5, 80131 Naples, Italy; (R.B.-P.); (M.K.); (G.D.R.); (F.S.)
- Telethon Institute of Genetics and Medicine, Via Campi Flegrei 34, 80078 Pozzuoli, Italy; (N.B.-P.); (S.B.)
| | - Francesco Testa
- Eye Clinic, Multidisciplinary Department of Medical, Surgical and Dental Sciences, Università degli Studi della Campania ‘Luigi Vanvitelli’, Via Pansini 5, 80131 Naples, Italy; (R.B.-P.); (M.K.); (G.D.R.); (F.S.)
- Correspondence:
| | - Gerarda Cappuccio
- Department of Translational Medicine, Federico II University, Via Pansini 5, 80131 Naples, Italy;
| | - Maria Elena Onore
- Medical Genetics, Department of Precision Medicine, Università degli Studi della Campania ‘Luigi Vanvitelli’, Via Luigi De Crecchio 7, 80138 Naples, Italy; (M.E.O.); (F.R.)
| | - Francesca Romano
- Medical Genetics, Department of Precision Medicine, Università degli Studi della Campania ‘Luigi Vanvitelli’, Via Luigi De Crecchio 7, 80138 Naples, Italy; (M.E.O.); (F.R.)
| | - Giuseppe De Rosa
- Eye Clinic, Multidisciplinary Department of Medical, Surgical and Dental Sciences, Università degli Studi della Campania ‘Luigi Vanvitelli’, Via Pansini 5, 80131 Naples, Italy; (R.B.-P.); (M.K.); (G.D.R.); (F.S.)
| | - Enrico Tedeschi
- Department of Advanced Biomedical Sciences, Federico II University, Via Pansini 5, 80131 Naples, Italy;
| | - Nicola Brunetti-Pierri
- Telethon Institute of Genetics and Medicine, Via Campi Flegrei 34, 80078 Pozzuoli, Italy; (N.B.-P.); (S.B.)
- Department of Translational Medicine, Federico II University, Via Pansini 5, 80131 Naples, Italy;
| | - Sandro Banfi
- Telethon Institute of Genetics and Medicine, Via Campi Flegrei 34, 80078 Pozzuoli, Italy; (N.B.-P.); (S.B.)
- Medical Genetics, Department of Precision Medicine, Università degli Studi della Campania ‘Luigi Vanvitelli’, Via Luigi De Crecchio 7, 80138 Naples, Italy; (M.E.O.); (F.R.)
| | - Francesca Simonelli
- Eye Clinic, Multidisciplinary Department of Medical, Surgical and Dental Sciences, Università degli Studi della Campania ‘Luigi Vanvitelli’, Via Pansini 5, 80131 Naples, Italy; (R.B.-P.); (M.K.); (G.D.R.); (F.S.)
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Turkyilmaz A, Geckinli BB, Alavanda C, Arslan Ates E, Buyukbayrak EE, Eren SF, Arman A. Meckel-Gruber Syndrome: Clinical and Molecular Genetic Profiles in Two Fetuses and Review of the Current Literature. Genet Test Mol Biomarkers 2021; 25:445-451. [PMID: 34096792 DOI: 10.1089/gtmb.2020.0311] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Background: Meckel-Gruber syndrome (MKS; OMIM No. 249000) is a rare, in utero lethal disease characterized by occipital encephalocele, polycystic kidneys, and polydactyly. Methodology and Results: In this study, two fetuses diagnosed as having MKS in the prenatal period were evaluated on the basis of ultrasonographic findings, postmortem autopsy findings, and molecular genetic analyses. Using exome sequencing analyses a novel homozygous frameshift variant (NM_015631: c.530delA, p.Lys177Argfs*47) was detected at exon 4 of TCTN3 gene in case 1, and a novel homozygous synonymous variant (NM_025114: c.180G>A, p Lys60Lys) was detected at exon 3 of CEP290 gene in case 2. Case 1 is the first reported case in the literature, which showed the typical MKS clinical feature with a novel frameshift variation in the TCTN3 gene. The variant in case 2 is the first reported synonymous variant of CEP290 gene in the literature, which has been shown to affect splicing in a functional study at the RNA level. Conclusion: TCTN3 gene variants that were rarely associated with the typical MKS phenotype and all cases with these variations have been discussed in the context of genotype-phenotype. The detection of the first synonymous variant of CEP290 gene and the demonstration of its effect on splicing by a functional study are likely to contribute to the molecular etiology of MKS.
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Affiliation(s)
- Ayberk Turkyilmaz
- Department of Medical Genetics, School of Medicine, Karadeniz Technical University, Trabzon, Turkey
| | - Bilgen Bilge Geckinli
- Department of Medical Genetics, School of Medicine, Marmara University, Istanbul, Turkey
| | - Ceren Alavanda
- Department of Medical Genetics, School of Medicine, Marmara University, Istanbul, Turkey
| | - Esra Arslan Ates
- Department of Medical Genetics, Marmara University Pendik Training and Research Hospital, Istanbul, Turkey
| | | | - Sirin Funda Eren
- Department of Pathology, School of Medicine, Marmara University, Istanbul, Turkey
| | - Ahmet Arman
- Department of Medical Genetics, School of Medicine, Marmara University, Istanbul, Turkey
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Sánchez-Bellver L, Toulis V, Marfany G. On the Wrong Track: Alterations of Ciliary Transport in Inherited Retinal Dystrophies. Front Cell Dev Biol 2021; 9:623734. [PMID: 33748110 PMCID: PMC7973215 DOI: 10.3389/fcell.2021.623734] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Accepted: 02/09/2021] [Indexed: 01/14/2023] Open
Abstract
Ciliopathies are a group of heterogeneous inherited disorders associated with dysfunction of the cilium, a ubiquitous microtubule-based organelle involved in a broad range of cellular functions. Most ciliopathies are syndromic, since several organs whose cells produce a cilium, such as the retina, cochlea or kidney, are affected by mutations in ciliary-related genes. In the retina, photoreceptor cells present a highly specialized neurosensory cilium, the outer segment, stacked with membranous disks where photoreception and phototransduction occurs. The daily renewal of the more distal disks is a unique characteristic of photoreceptor outer segments, resulting in an elevated protein demand. All components necessary for outer segment formation, maintenance and function have to be transported from the photoreceptor inner segment, where synthesis occurs, to the cilium. Therefore, efficient transport of selected proteins is critical for photoreceptor ciliogenesis and function, and any alteration in either cargo delivery to the cilium or intraciliary trafficking compromises photoreceptor survival and leads to retinal degeneration. To date, mutations in more than 100 ciliary genes have been associated with retinal dystrophies, accounting for almost 25% of these inherited rare diseases. Interestingly, not all mutations in ciliary genes that cause retinal degeneration are also involved in pleiotropic pathologies in other ciliated organs. Depending on the mutation, the same gene can cause syndromic or non-syndromic retinopathies, thus emphasizing the highly refined specialization of the photoreceptor neurosensory cilia, and raising the possibility of photoreceptor-specific molecular mechanisms underlying common ciliary functions such as ciliary transport. In this review, we will focus on ciliary transport in photoreceptor cells and discuss the molecular complexity underpinning retinal ciliopathies, with a special emphasis on ciliary genes that, when mutated, cause either syndromic or non-syndromic retinal ciliopathies.
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Affiliation(s)
- Laura Sánchez-Bellver
- Departament de Genètica, Microbiologia i Estadística, Universitat de Barcelona, Barcelona, Spain
- Institute of Biomedicine (IBUB-IRSJD), Universitat de Barcelona, Barcelona, Spain
| | - Vasileios Toulis
- Departament de Genètica, Microbiologia i Estadística, Universitat de Barcelona, Barcelona, Spain
- CIBERER, ISCIII, Universitat de Barcelona, Barcelona, Spain
| | - Gemma Marfany
- Departament de Genètica, Microbiologia i Estadística, Universitat de Barcelona, Barcelona, Spain
- Institute of Biomedicine (IBUB-IRSJD), Universitat de Barcelona, Barcelona, Spain
- CIBERER, ISCIII, Universitat de Barcelona, Barcelona, Spain
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Lange KI, Tsiropoulou S, Kucharska K, Blacque OE. Interpreting the pathogenicity of Joubert syndrome missense variants in Caenorhabditis elegans. Dis Model Mech 2021; 14:dmm.046631. [PMID: 33234550 PMCID: PMC7859701 DOI: 10.1242/dmm.046631] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Accepted: 11/13/2020] [Indexed: 12/26/2022] Open
Abstract
Ciliopathies are inherited disorders caused by defects in motile and non-motile (primary) cilia. Ciliopathy syndromes and associated gene variants are often highly pleiotropic and represent exemplars for interrogating genotype-phenotype correlations. Towards understanding disease mechanisms in the context of ciliopathy mutations, we have used a leading model organism for cilia and ciliopathy research, Caenorhabditis elegans, together with gene editing, to characterise two missense variants (P74S and G155S) in mksr-2/B9D2 associated with Joubert syndrome (JBTS). B9D2 functions within the Meckel syndrome (MKS) module at the ciliary base transition zone (TZ) compartment and regulates the molecular composition and sensory/signalling functions of the cilium. Quantitative assays of cilium/TZ structure and function, together with knock-in reporters, confirm that both variant alleles are pathogenic in worms. G155S causes a more severe overall phenotype and disrupts endogenous MKSR-2 organisation at the TZ. Recapitulation of the patient biallelic genotype shows that compound heterozygous worms phenocopy worms homozygous for P74S. The P74S and G155S alleles also reveal evidence of a very close functional association between the B9D2-associated B9 complex and MKS-2/TMEM216. Together, these data establish C. elegans as a model for interpreting JBTS mutations and provide further insight into MKS module organisation. This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Karen I Lange
- School of Biomolecular and Biomedical Science, Conway Institute, University College Dublin, Dublin 4, Ireland
| | - Sofia Tsiropoulou
- School of Biomolecular and Biomedical Science, Conway Institute, University College Dublin, Dublin 4, Ireland
| | - Katarzyna Kucharska
- School of Biomolecular and Biomedical Science, Conway Institute, University College Dublin, Dublin 4, Ireland
| | - Oliver E Blacque
- School of Biomolecular and Biomedical Science, Conway Institute, University College Dublin, Dublin 4, Ireland
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Luo M, He R, Lin Z, Shen Y, Zhang G, Cao Z, Lu C, Meng D, Zhang J, Ma X, Cao M. Novel Compound Heterozygous Variants in MKS1 Leading to Joubert Syndrome. Front Genet 2020; 11:576235. [PMID: 33193692 PMCID: PMC7592398 DOI: 10.3389/fgene.2020.576235] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Accepted: 09/14/2020] [Indexed: 11/13/2022] Open
Abstract
Joubert syndrome (JBTS) and Meckel-Gruber syndrome (MKS) are rare recessive disorders caused by defects of cilia, and they share overlapping clinical features and allelic loci. Mutations of MKS1 contribute approximately 7% to all MKS cases and are found in some JBTS patients. Here, we describe a JBTS patient with two novel mutations of MKS1. Whole exome sequencing (WES) revealed c.191-1G > A and c.1058delG compound heterozygous variants. The patient presented with typical cerebellar vermis hypoplasia, hypotonia, and developmental delay, but without other renal/hepatic involvement or polydactyly. Functional studies showed that the c.1058delG mutation disrupts the B9 domain of MKS1, attenuates the interactions with B9D2, and impairs its ciliary localization at the transition zone (TZ), indicating that the B9 domain of MKS1 is essential for the integrity of the B9 protein complex and localization of MKS1 at the TZ. This work expands the mutation spectrum of MKS1 and elucidates the clinical heterogeneity of MKS1-related ciliopathies.
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Affiliation(s)
- Minna Luo
- National Research Institute for Family Planning, Beijing, China.,National Human Genetic Resources Center, Beijing, China
| | - Ruida He
- Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Department of Pathophysiology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Zaisheng Lin
- Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Department of Pathophysiology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yue Shen
- National Research Institute for Family Planning, Beijing, China.,National Human Genetic Resources Center, Beijing, China
| | - Guangyu Zhang
- Department of Children Rehabilitation, The Third Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Zongfu Cao
- National Research Institute for Family Planning, Beijing, China.,National Human Genetic Resources Center, Beijing, China
| | - Chao Lu
- National Research Institute for Family Planning, Beijing, China.,National Human Genetic Resources Center, Beijing, China
| | - Dan Meng
- Tianjin Key Laboratory of Food and Biotechnology, School of Biotechnology and Food Science, Tianjin University of Commerce, Tianjin, China
| | - Jing Zhang
- Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Department of Pathophysiology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Xu Ma
- National Research Institute for Family Planning, Beijing, China.,National Human Genetic Resources Center, Beijing, China
| | - Muqing Cao
- Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Department of Pathophysiology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
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Wang SF, Kowal TJ, Ning K, Koo EB, Wu AY, Mahajan VB, Sun Y. Review of Ocular Manifestations of Joubert Syndrome. Genes (Basel) 2018; 9:E605. [PMID: 30518138 DOI: 10.3390/genes9120605] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2018] [Revised: 11/13/2018] [Accepted: 11/27/2018] [Indexed: 12/13/2022] Open
Abstract
Joubert syndrome is a group of rare disorders that stem from defects in a sensory organelle, the primary cilia. Affected patients often present with disorders involving multiple organ systems, including the brain, eyes, and kidneys. Common symptoms include breathing abnormalities, mental developmental delays, loss of voluntary muscle coordination, and abnormal eye movements, with a diagnostic “molar tooth” sign observed by magnetic resonance imaging (MRI) of the midbrain. We reviewed the ocular phenotypes that can be found in patients with Joubert syndrome. Ocular motor apraxia is the most frequent (80% of patients), followed by strabismus (74%) and nystagmus (72%). A minority of patients also present with ptosis (43%), chorioretinal coloboma (30%), and optic nerve atrophy (22%). Although mutations in 34 genes have been found to be associated with Joubert syndrome, retinal degeneration has been reported in only 38% of patients. Mutations in AHI1 and CEP290, genes critical to primary cilia function, have been linked to retinal degeneration. In conclusion, Joubert syndrome is a rare pleiotropic group of disorders with variable ocular presentations.
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Hua K, Ferland RJ. Primary cilia proteins: ciliary and extraciliary sites and functions. Cell Mol Life Sci 2018; 75:1521-1540. [PMID: 29305615 DOI: 10.1007/s00018-017-2740-5] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Revised: 12/21/2017] [Accepted: 12/27/2017] [Indexed: 02/07/2023]
Abstract
Primary cilia are immotile organelles known for their roles in development and cell signaling. Defects in primary cilia result in a range of disorders named ciliopathies. Because this organelle can be found singularly on almost all cell types, its importance extends to most organ systems. As such, elucidating the importance of the primary cilium has attracted researchers from all biological disciplines. As the primary cilia field expands, caution is warranted in attributing biological defects solely to the function of this organelle, since many of these "ciliary" proteins are found at other sites in cells and likely have non-ciliary functions. Indeed, many, if not all, cilia proteins have locations and functions outside the primary cilium. Extraciliary functions are known to include cell cycle regulation, cytoskeletal regulation, and trafficking. Cilia proteins have been observed in the nucleus, at the Golgi apparatus, and even in immune synapses of T cells (interestingly, a non-ciliated cell). Given the abundance of extraciliary sites and functions, it can be difficult to definitively attribute an observed phenotype solely to defective cilia rather than to some defective extraciliary function or a combination of both. Thus, extraciliary sites and functions of cilia proteins need to be considered, as well as experimentally determined. Through such consideration, we will understand the true role of the primary cilium in disease as compared to other cellular processes' influences in mediating disease (or through a combination of both). Here, we review a compilation of known extraciliary sites and functions of "cilia" proteins as a means to demonstrate the potential non-ciliary roles for these proteins.
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Affiliation(s)
- Kiet Hua
- Department of Neuroscience and Experimental Therapeutics, Albany Medical College, 47 New Scotland Avenue, MC-136, Albany, NY, 12208, USA.
| | - Russell J Ferland
- Department of Neuroscience and Experimental Therapeutics, Albany Medical College, 47 New Scotland Avenue, MC-136, Albany, NY, 12208, USA. .,Department of Neurology, Albany Medical College, Albany, NY, 12208, USA.
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König JC, Titieni A, Konrad M. Network for Early Onset Cystic Kidney Diseases-A Comprehensive Multidisciplinary Approach to Hereditary Cystic Kidney Diseases in Childhood. Front Pediatr 2018; 6:24. [PMID: 29497606 PMCID: PMC5819567 DOI: 10.3389/fped.2018.00024] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Accepted: 01/25/2018] [Indexed: 12/16/2022] Open
Abstract
Hereditary cystic kidney diseases comprise a complex group of genetic disorders representing one of the most common causes of end-stage renal failure in childhood. The main representatives are autosomal recessive polycystic kidney disease, nephronophthisis, Bardet-Biedl syndrome, and hepatocyte nuclear factor-1beta nephropathy. Within the last years, genetic efforts have brought tremendous progress for the molecular understanding of hereditary cystic kidney diseases identifying more than 70 genes. Yet, genetic heterogeneity, phenotypic variability, a lack of reliable genotype-phenotype correlations and the absence of disease-specific biomarkers remain major challenges for physicians treating children with cystic kidney diseases. To tackle these challenges comprehensive scientific approaches are urgently needed that match the ongoing "revolution" in genetics and molecular biology with an improved efficacy of clinical data collection. Network for early onset cystic kidney diseases (NEOCYST) is a multidisciplinary, multicenter collaborative combining a detailed collection of clinical data with translational scientific approaches addressing the genetic, molecular, and functional background of hereditary cystic kidney diseases. Consisting of seven work packages, including an international registry as well as a biobank, NEOCYST is not only dedicated to current scientific questions, but also provides a platform for longitudinal clinical surveillance and provides precious sources for high-quality research projects and future clinical trials. Funded by the German Federal Government, the NEOCYST collaborative started in February 2016. Here, we would like to introduce the rationale, design, and objectives of the network followed by a short overview on the current state of progress.
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Affiliation(s)
- Jens Christian König
- Department of General Pediatrics, University Children's Hospital Münster, Münster, Germany
| | - Andrea Titieni
- Department of General Pediatrics, University Children's Hospital Münster, Münster, Germany
| | - Martin Konrad
- Department of General Pediatrics, University Children's Hospital Münster, Münster, Germany
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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: 84] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [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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