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Niceta M, Pizzi S, Inzana F, Peron A, Bakhtiari S, Nizon M, Levy J, Mancini C, Cogné B, Radio FC, Agolini E, Cocciadiferro D, Novelli A, Salih MA, Recalcati MP, Arancio R, Besnard M, Tabet A, Kruer MC, Priolo M, Dallapiccola B, Tartaglia M. Delineation of the clinical profile of CNOT2 haploinsufficiency and overview of the IDNADFS phenotype. Clin Genet 2023; 103:156-166. [PMID: 36224108 PMCID: PMC9939052 DOI: 10.1111/cge.14247] [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] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Revised: 10/06/2022] [Accepted: 10/08/2022] [Indexed: 01/07/2023]
Abstract
CNOT2 haploinsufficiency underlies a rare neurodevelopmental disorder named Intellectual Developmental disorder with NAsal speech, Dysmorphic Facies, and variable Skeletal anomalies (IDNADFS, OMIM 618608). The condition clinically overlaps with chromosome 12q15 deletion syndrome, suggesting a major contribution of CNOT2 haploinsufficiency to the latter. CNOT2 is a member of the CCR4-NOT complex, which is a master regulator of multiple cellular processes, including gene expression, RNA deadenylation, and protein ubiquitination. To date, less than 20 pathogenic 12q15 microdeletions encompassing CNOT2, together with a single truncating variant of the gene, and two large intragenic deletions have been reported. Due to the small number of affected subjects described so far, the clinical profile of IDNADFS has not been fully delineated. Here we report five unrelated individuals, three of which carrying de novo intragenic CNOT2 variants, one presenting with a multiexon intragenic deletion, and an additional case of 12q15 microdeletion syndrome. Finally, we assess the features of IDNADFS by reviewing published and present affected individuals and reevaluate the clinical phenotype of this neurodevelopmental disorder.
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Affiliation(s)
- Marcello Niceta
- Genetics and Rare DiseasesBambino Gesù Children's Hospital, IRCCSRomeItaly
- Department of PediatricsSapienza UniversityRomeItaly
| | - Simone Pizzi
- Genetics and Rare DiseasesBambino Gesù Children's Hospital, IRCCSRomeItaly
| | - Francesca Inzana
- Genetic Counseling ServiceRegional Hospital of BolzanoBolzanoItaly
| | - Angela Peron
- Medical GeneticsASST Santi Paolo e Carlo, Ospedale San PaoloMilanItaly
- Division of Medical Genetics, Department of PediatricsUniversity of UtahSalt Lake CityUtahUSA
| | - Somayeh Bakhtiari
- Pediatric Movement Disorders Program, Division of Pediatric NeurologyBarrow Neurological Institute, Phoenix Children's HospitalPhoenixArizonaUSA
- Departments of Child Health, Neurology, and Cellular and Molecular Medicine, and Program in GeneticsUniversity of Arizona College of Medicine – PhoenixPhoenixArizonaUSA
| | - Mathilde Nizon
- CHU Nantes, Service de Génétique MédicaleL'institut du thorax, INSERM, CNRS, UNIV NantesNantesFrance
| | - Jonathan Levy
- Genetics DepartmentAP‐HP, Robert‐Debré University HospitalParisFrance
| | - Cecilia Mancini
- Genetics and Rare DiseasesBambino Gesù Children's Hospital, IRCCSRomeItaly
| | - Benjamin Cogné
- Laboratoire de Génétique MoléculaireCHU de NantesNantesFrance
| | | | - Emanuele Agolini
- Translational Cytogenomics Research UnitBambino Gesù Children's Hospital, IRCCSRomeItaly
| | - Dario Cocciadiferro
- Translational Cytogenomics Research UnitBambino Gesù Children's Hospital, IRCCSRomeItaly
| | - Antonio Novelli
- Translational Cytogenomics Research UnitBambino Gesù Children's Hospital, IRCCSRomeItaly
| | - Mustafa A. Salih
- Neurology Division, Department of PediatricsCollege of Medicine, King Saud UniversityRiyadhSaudi Arabia
- Department of PediatricsCollege of Medicine, Almughtaribeen UniversityKhartoumSudan
| | - Maria Paola Recalcati
- Medical Cytogenetics LaboratoryIstituto Auxologico Italiano IRCCSCusano MilaninoItaly
| | - Rosangela Arancio
- Clinica PediatricaOspedale San Paolo, ASST Santi Paolo CarloMilanItaly
| | - Marianne Besnard
- Service de NéonatologieCentre Hospitalier de Polynésie FrançaisePapeeteFrench Polynesia
| | - Anne‐Claude Tabet
- Human Genetics and Cognitive FunctionsInstitut Pasteur, UMR3571 CNRS, Université de ParisParisFrance
- Cytogenetic UnitRobert Debré Hospital, APHPParisFrance
| | - Michael C. Kruer
- Departments of Child Health, Neurology, and Cellular and Molecular Medicine, and Program in GeneticsUniversity of Arizona College of Medicine – PhoenixPhoenixArizonaUSA
| | - Manuela Priolo
- UOSD Genetica MedicaGrande Ospedale Metropolitano “Bianchi‐Melacrino‐Morelli”Reggio CalabriaItaly
| | - Bruno Dallapiccola
- Genetics and Rare DiseasesBambino Gesù Children's Hospital, IRCCSRomeItaly
| | - Marco Tartaglia
- Genetics and Rare DiseasesBambino Gesù Children's Hospital, IRCCSRomeItaly
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Chong JX, Talbot JC, Teets EM, Previs S, Martin BL, Shively KM, Marvin CT, Aylsworth AS, Saadeh-Haddad R, Schatz UA, Inzana F, Ben-Omran T, Almusafri F, Al-Mulla M, Buckingham KJ, Harel T, Mor-Shaked H, Radhakrishnan P, Girisha KM, Nayak SS, Shukla A, Dieterich K, Faure J, Rendu J, Capri Y, Latypova X, Nickerson DA, Warshaw D, Janssen PM, Amacher SL, Bamshad MJ, Bamshad MJ. Response to Hall et al. Am J Hum Genet 2020; 107:1188-1189. [PMID: 33275912 DOI: 10.1016/j.ajhg.2020.11.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | - Michael J Bamshad
- Division of Genetic Medicine, Department of Pediatrics, University of Washington, Seattle, WA 98195, USA; Brotman-Baty Institute, Seattle, WA 98195, USA; Department of Genome Sciences, University of Washington, Seattle, WA 98195, USA; Seattle Children's Hospital, Seattle, WA 98105, USA.
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Chong JX, Talbot JC, Teets EM, Previs S, Martin BL, Shively KM, Marvin CT, Aylsworth AS, Saadeh-Haddad R, Schatz UA, Inzana F, Ben-Omran T, Almusafri F, Al-Mulla M, Buckingham KJ, Harel T, Mor-Shaked H, Radhakrishnan P, Girisha KM, Nayak SS, Shukla A, Dieterich K, Faure J, Rendu J, Capri Y, Latypova X, Nickerson DA, Warshaw DM, Janssen PM, Amacher SL, Bamshad MJ, Bamshad MJ. Mutations in MYLPF Cause a Novel Segmental Amyoplasia that Manifests as Distal Arthrogryposis. Am J Hum Genet 2020; 107:293-310. [PMID: 32707087 DOI: 10.1016/j.ajhg.2020.06.014] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [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: 05/02/2020] [Accepted: 06/18/2020] [Indexed: 02/06/2023] Open
Abstract
We identified ten persons in six consanguineous families with distal arthrogryposis (DA) who had congenital contractures, scoliosis, and short stature. Exome sequencing revealed that each affected person was homozygous for one of two different rare variants (c.470G>T [p.Cys157Phe] or c.469T>C [p.Cys157Arg]) affecting the same residue of myosin light chain, phosphorylatable, fast skeletal muscle (MYLPF). In a seventh family, a c.487G>A (p.Gly163Ser) variant in MYLPF arose de novo in a father, who transmitted it to his son. In an eighth family comprised of seven individuals with dominantly inherited DA, a c.98C>T (p.Ala33Val) variant segregated in all four persons tested. Variants in MYLPF underlie both dominant and recessively inherited DA. Mylpf protein models suggest that the residues associated with dominant DA interact with myosin whereas the residues altered in families with recessive DA only indirectly impair this interaction. Pathological and histological exam of a foot amputated from an affected child revealed complete absence of skeletal muscle (i.e., segmental amyoplasia). To investigate the mechanism for this finding, we generated an animal model for partial MYLPF impairment by knocking out zebrafish mylpfa. The mylpfa mutant had reduced trunk contractile force and complete pectoral fin paralysis, demonstrating that mylpf impairment most severely affects limb movement. mylpfa mutant muscle weakness was most pronounced in an appendicular muscle and was explained by reduced myosin activity and fiber degeneration. Collectively, our findings demonstrate that partial loss of MYLPF function can lead to congenital contractures, likely as a result of degeneration of skeletal muscle in the distal limb.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | - Michael J Bamshad
- Division of Genetic Medicine, Department of Pediatrics, University of Washington, Seattle, WA 98195, USA; Brotman-Baty Institute, Seattle, WA 98195, USA; Department of Genome Sciences, University of Washington, Seattle, WA 98195, USA; Seattle Children's Hospital, Seattle, WA 98105, USA.
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4
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Benedicenti F, Stanzial F, Wischmeijer A, Inzana F. "Spot diagnosis" or "spot the diagnosis"? J Neurol Sci 2017; 379:335-336. [PMID: 28583319 DOI: 10.1016/j.jns.2017.05.063] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Accepted: 05/29/2017] [Indexed: 11/29/2022]
Affiliation(s)
- Francesco Benedicenti
- Clinical Genetics Service and South Tyrol Coordination Center for Rare Diseases, Department of Pediatrics, Regional Hospital of Bolzano, Viale Europa, 31, 39100 Bolzano, Italy.
| | - Franco Stanzial
- Clinical Genetics Service and South Tyrol Coordination Center for Rare Diseases, Department of Pediatrics, Regional Hospital of Bolzano, Viale Europa, 31, 39100 Bolzano, Italy
| | - Anita Wischmeijer
- Clinical Genetics Service and South Tyrol Coordination Center for Rare Diseases, Department of Pediatrics, Regional Hospital of Bolzano, Viale Europa, 31, 39100 Bolzano, Italy
| | - Francesca Inzana
- Clinical Genetics Service and South Tyrol Coordination Center for Rare Diseases, Department of Pediatrics, Regional Hospital of Bolzano, Viale Europa, 31, 39100 Bolzano, Italy
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Nicchia E, Benedicenti F, De Rocco D, Greco C, Bottega R, Inzana F, Faleschini M, Bonin S, Cappelli E, Mogni M, Stanzial F, Svahn J, Dufour C, Savoia A. Clinical aspects of Fanconi anemia individuals with the same mutation of FANCF identified by next generation sequencing. ACTA ACUST UNITED AC 2015; 103:1003-10. [PMID: 26033879 DOI: 10.1002/bdra.23388] [Citation(s) in RCA: 3] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
BACKGROUND Fanconi anemia (FA) is a rare genetic disease characterized by congenital malformations, aplastic anemia and increased risk of developing malignancies. FA is genetically heterogeneous as it is caused by at least 17 different genes. Among these, FANCA, FANCC, and FANCG account for approximately 85% of the patients whereas the remaining genes are mutated in only a small percentage of cases. For this reason, the molecular diagnostic process is complex and not always extended to all the FA genes, preventing the characterization of individuals belonging to rare groups. METHODS The FA genes were analyzed using a next generation sequencing approach in two unrelated families. RESULTS The analysis identified the same, c.484_485del, homozygous mutation of FANCF in both families. A careful examination of three electively aborted fetuses in one family and one affected girl in the other indicated an association of the FANCF loss-of-function mutation with a severe phenotype characterized by multiple malformations. CONCLUSION The systematic use of next generation sequencing will allow the recognition of individuals from rare complementation groups, a better definition of their clinical phenotypes, and consequently, an appropriate genetic counseling.
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Affiliation(s)
- Elena Nicchia
- Department of Medical Sciences, University of Trieste, Trieste, Italy
| | - Francesco Benedicenti
- Genetic Counseling Service, Department of Pediatrics, Regional Hospital of Bolzano, Bolzano, Italy
| | - Daniela De Rocco
- Institute for Maternal and Child Health - IRCCS Burlo Garofolo, Trieste, Italy
| | - Chiara Greco
- Institute for Maternal and Child Health - IRCCS Burlo Garofolo, Trieste, Italy
| | - Roberta Bottega
- Institute for Maternal and Child Health - IRCCS Burlo Garofolo, Trieste, Italy
| | - Francesca Inzana
- Genetic Counseling Service, Department of Pediatrics, Regional Hospital of Bolzano, Bolzano, Italy
| | | | - Serena Bonin
- Department of Medical Sciences, University of Trieste, Trieste, Italy
| | - Enrico Cappelli
- Clinical and Experimental Hematology Unit, G. Gaslini Children's Hospital, Genoa, Italy
| | - Massimo Mogni
- Human Genetics Laboratory "E.O. Ospedali Galliera", Genoa, Italy
| | - Franco Stanzial
- Genetic Counseling Service, Department of Pediatrics, Regional Hospital of Bolzano, Bolzano, Italy
| | - Johanna Svahn
- Clinical and Experimental Hematology Unit, G. Gaslini Children's Hospital, Genoa, Italy
| | - Carlo Dufour
- Clinical and Experimental Hematology Unit, G. Gaslini Children's Hospital, Genoa, Italy
| | - Anna Savoia
- Department of Medical Sciences, University of Trieste, Trieste, Italy.,Institute for Maternal and Child Health - IRCCS Burlo Garofolo, Trieste, Italy
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6
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Kohl S, Zobor D, Chiang WC, Weisschuh N, Staller J, Gonzalez Menendez I, Chang S, Beck SC, Garcia Garrido M, Sothilingam V, Seeliger MW, Stanzial F, Benedicenti F, Inzana F, Héon E, Vincent A, Beis J, Strom TM, Rudolph G, Roosing S, Hollander AID, Cremers FPM, Lopez I, Ren H, Moore AT, Webster AR, Michaelides M, Koenekoop RK, Zrenner E, Kaufman RJ, Tsang SH, Wissinger B, Lin JH. Mutations in the unfolded protein response regulator ATF6 cause the cone dysfunction disorder achromatopsia. Nat Genet 2015; 47:757-65. [PMID: 26029869 DOI: 10.1038/ng.3319] [Citation(s) in RCA: 158] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2014] [Accepted: 05/04/2015] [Indexed: 01/10/2023]
Abstract
Achromatopsia (ACHM) is an autosomal recessive disorder characterized by color blindness, photophobia, nystagmus and severely reduced visual acuity. Using homozygosity mapping and whole-exome and candidate gene sequencing, we identified ten families carrying six homozygous and two compound-heterozygous mutations in the ATF6 gene (encoding activating transcription factor 6A), a key regulator of the unfolded protein response (UPR) and cellular endoplasmic reticulum (ER) homeostasis. Patients had evidence of foveal hypoplasia and disruption of the cone photoreceptor layer. The ACHM-associated ATF6 mutations attenuate ATF6 transcriptional activity in response to ER stress. Atf6(-/-) mice have normal retinal morphology and function at a young age but develop rod and cone dysfunction with increasing age. This new ACHM-related gene suggests a crucial and unexpected role for ATF6A in human foveal development and cone function and adds to the list of genes that, despite ubiquitous expression, when mutated can result in an isolated retinal photoreceptor phenotype.
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Affiliation(s)
- Susanne Kohl
- Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tübingen, Tübingen, Germany
| | - Ditta Zobor
- Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tübingen, Tübingen, Germany
| | - Wei-Chieh Chiang
- Department of Pathology, University of California, San Diego, La Jolla, California, USA
| | - Nicole Weisschuh
- Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tübingen, Tübingen, Germany
| | - Jennifer Staller
- Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tübingen, Tübingen, Germany
| | - Irene Gonzalez Menendez
- Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tübingen, Tübingen, Germany
| | - Stanley Chang
- 1] Department of Ophthalmology, Columbia University, New York, New York, USA. [2] Edward Harkness Eye Institute, New York Presbyterian Hospital, New York, New York, USA
| | - Susanne C Beck
- Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tübingen, Tübingen, Germany
| | - Marina Garcia Garrido
- Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tübingen, Tübingen, Germany
| | - Vithiyanjali Sothilingam
- Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tübingen, Tübingen, Germany
| | - Mathias W Seeliger
- Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tübingen, Tübingen, Germany
| | - Franco Stanzial
- Clinical Genetics Service, Regional Hospital Bozen, Bozen, Italy
| | | | - Francesca Inzana
- Clinical Genetics Service, Regional Hospital Bozen, Bozen, Italy
| | - Elise Héon
- Department of Ophthalmology and Vision Sciences, Programme of Genetics and Genomic Medicine, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
| | - Ajoy Vincent
- Department of Ophthalmology and Vision Sciences, Programme of Genetics and Genomic Medicine, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
| | - Jill Beis
- Medical Genetics, IWK Health Centre, Halifax, Nova Scotia, Canada
| | - Tim M Strom
- 1] Institute of Human Genetics, Helmholtz Zentrum München, Neuherberg, Germany. [2] Institute of Human Genetics, Technische Universität München, Munich, Germany
| | - Günther Rudolph
- University Eye Hospital, Ludwig Maximilians University, Munich, Germany
| | - Susanne Roosing
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Anneke I den Hollander
- 1] Department of Human Genetics, Radboud University Medical Center, Nijmegen, the Netherlands. [2] Department of Ophthalmology, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Frans P M Cremers
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Irma Lopez
- McGill Ocular Genetics Centre, McGill University Health Centre, Montreal, Quebec, Canada
| | - Huanan Ren
- McGill Ocular Genetics Centre, McGill University Health Centre, Montreal, Quebec, Canada
| | - Anthony T Moore
- 1] University College London Institute of Ophthalmology, University College London, London, UK. [2] Moorfields Eye Hospital, London, UK. [3] Ophthalmology Department, University of California San Francisco Medical School, San Francisco, California, USA
| | - Andrew R Webster
- 1] University College London Institute of Ophthalmology, University College London, London, UK. [2] Moorfields Eye Hospital, London, UK
| | - Michel Michaelides
- 1] University College London Institute of Ophthalmology, University College London, London, UK. [2] Moorfields Eye Hospital, London, UK
| | - Robert K Koenekoop
- McGill Ocular Genetics Centre, McGill University Health Centre, Montreal, Quebec, Canada
| | - Eberhart Zrenner
- 1] Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tübingen, Tübingen, Germany. [2] Werner Reichardt Center for Integrative Neuroscience, University of Tübingen, Tübingen, Germany
| | - Randal J Kaufman
- Degenerative Diseases Program, Sanford-Burnham Medical Research Institute, La Jolla, California, USA
| | - Stephen H Tsang
- 1] Department of Ophthalmology, Columbia University, New York, New York, USA. [2] Jonas Laboratory of Stem Cell and Regenerative Medicine, Columbia University, New York, New York, USA. [3] Brown Glaucoma Laboratory, Columbia University, New York, New York, USA. [4] Institute of Human Nutrition, Columbia University, New York, New York, USA. [5] Department of Pathology and Cell Biology, Columbia University, New York, New York, USA
| | - Bernd Wissinger
- Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tübingen, Tübingen, Germany
| | - Jonathan H Lin
- 1] Department of Pathology, University of California, San Diego, La Jolla, California, USA. [2] Department of Ophthalmology, University of California, San Diego, La Jolla, California, USA
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7
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Novara F, Stanzial F, Rossi E, Benedicenti F, Inzana F, Di Gregorio E, Brusco A, Graakjaer J, Fagerberg C, Belligni E, Silengo M, Zuffardi O, Ciccone R. Defining the phenotype associated with microduplication reciprocal to Sotos syndrome microdeletion. Am J Med Genet A 2014; 164A:2084-90. [PMID: 24819041 DOI: 10.1002/ajmg.a.36591] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [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: 07/15/2013] [Accepted: 03/31/2014] [Indexed: 11/08/2022]
Abstract
NSD1 point mutations, submicroscopic deletions and intragenic deletions are the major cause of Sotos syndrome, characterized by pre-postnatal generalized overgrowth with advanced bone age, learning disability, seizures, distinctive facial phenotype. Reverse clinical phenotype due to 5q35 microduplication encompassing NSD1 gene has been reported so far in 27 cases presenting with delayed bone age, microcephaly, failure to thrive and seizures in some cases, further supporting a gene dosage effect of NSD1 on growth regulation and neurological functions. Here we depict the clinical presentation of three new cases with 5q35 microduplication outlining a novel syndrome characterized by microcephaly, short stature, developmental delay and in some cases delayed bone maturation, without any typical facial or osseous anomalies.
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Affiliation(s)
- Francesca Novara
- Department of Molecular Medicine, University of Pavia, Pavia, Italy
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8
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Krieger M, Roos A, Stendel C, Claeys KG, Sonmez FM, Baudis M, Bauer P, Bornemann A, de Goede C, Dufke A, Finkel RS, Goebel HH, Häussler M, Kingston H, Kirschner J, Medne L, Muschke P, Rivier F, Rudnik-Schöneborn S, Spengler S, Inzana F, Stanzial F, Benedicenti F, Synofzik M, Lia Taratuto A, Pirra L, Tay SKH, Topaloglu H, Uyanik G, Wand D, Williams D, Zerres K, Weis J, Senderek J. SIL1 mutations and clinical spectrum in patients with Marinesco-Sjogren syndrome. ACTA ACUST UNITED AC 2013; 136:3634-44. [PMID: 24176978 DOI: 10.1093/brain/awt283] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Marinesco-Sjögren syndrome is a rare autosomal recessive multisystem disorder featuring cerebellar ataxia, early-onset cataracts, chronic myopathy, variable intellectual disability and delayed motor development. More recently, mutations in the SIL1 gene, which encodes an endoplasmic reticulum resident co-chaperone, were identified as the main cause of Marinesco-Sjögren syndrome. Here we describe the results of SIL1 mutation analysis in 62 patients presenting with early-onset ataxia, cataracts and myopathy or combinations of at least two of these. We obtained a mutation detection rate of 60% (15/25) among patients with the characteristic Marinesco-Sjögren syndrome triad (ataxia, cataracts, myopathy) whereas the detection rate in the group of patients with more variable phenotypic presentation was below 3% (1/37). We report 16 unrelated families with a total of 19 different SIL1 mutations. Among these mutations are 15 previously unreported changes, including single- and multi-exon deletions. Based on data from our screening cohort and data compiled from the literature we found that SIL1 mutations are invariably associated with the combination of a cerebellar syndrome and chronic myopathy. Cataracts were observed in all patients beyond the age of 7 years, but might be missing in infants. Six patients with SIL1 mutations had no intellectual disability, extending the known wide range of cognitive capabilities in Marinesco-Sjögren syndrome to include normal intelligence. Modestly constant features were somatic growth retardation, skeletal abnormalities and pyramidal tract signs. Examination of mutant SIL1 expression in cultured patient lymphoblasts suggested that SIL1 mutations result in severely reduced SIL1 protein levels irrespective of the type and position of mutations. Our data broaden the SIL1 mutation spectrum and confirm that SIL1 is the major Marinesco-Sjögren syndrome gene. SIL1 patients usually present with the characteristic triad but cataracts might be missing in young children. As cognitive impairment is not obligatory, patients without intellectual disability but a Marinesco-Sjögren syndrome-compatible phenotype should receive SIL1 mutation analysis. Despite allelic heterogeneity and many families with private mutations, the phenotype related to SIL1 mutations is relatively homogenous. Based on SIL1 expression studies we speculate that this may arise from a uniform effect of different mutations on protein expression.
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Affiliation(s)
- Michael Krieger
- 1 Institute of Human Genetics, Rheinisch-Westfälische Technische Hochschule (RWTH) Aachen University, 52074 Aachen, Germany
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