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Giacomini T, Cordani R, Bagnasco I, Vercellino F, Giordano L, Milito G, Ferrero GB, Mandrile G, Scala M, Meli M, Falsaperla R, Luria G, De Grandis E, Canale E, Amadori E, Striano P, Nobili L, Siri L. Electroclinical Features of Epilepsy in Kleefstra Syndrome. Neuropediatrics 2023; 54:433-438. [PMID: 37802085 DOI: 10.1055/s-0043-1775977] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/08/2023]
Abstract
BACKGROUND Kleefstra syndrome (KS) or 9q34.3 microdeletion syndrome (OMIM #610253) is a rare genetic condition featuring intellectual disability, hypotonia, and dysmorphic facial features. Autism spectrum disorder, severe language impairment, and sleep disorders have also been described. The syndrome can be either caused by a microdeletion in 9q34.3 or by pathogenic variants in the euchromatin histone methyltransferase 1 gene (EHMT1, *607001). Although epilepsy has been reported in 20 to 30% of subjects, a detailed description of epileptic features and underlying etiology is still lacking. The purpose of this study is to investigate epilepsy features in a cohort of epileptic patients with KS. METHODS This multicenter study investigated eight patients with KS and epilepsy. Our findings were compared with literature data. RESULTS We included five patients with 9q or 9q34.33 deletions, a subject with a complex translocation involving EHMT1, and two with pathogenic EHMT1 variants. All patients presented with moderate to severe developmental delay, language impairment, microcephaly, and infantile hypotonia. Although the epileptic manifestations were heterogeneous, most patients experienced focal seizures. The seizure frequency differs according to the age of epilepsy onset, with patients with early-onset epilepsy (before 36 months of age) presenting more frequent seizures. An overtime reduction in seizure frequency, as well as in antiseizure drug number, was observed in all patients. Developmental delay degree did not correlate with seizure onset and frequency or drug resistance. CONCLUSION Epilepsy is a frequent finding in KS, but the underlying pathogenetic mechanism and specific features remain elusive.
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Affiliation(s)
- Thea Giacomini
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics and Maternal and Child Health (DINOGMI), University of Genova, Genova, Italy
- Neuroradiology Unit, IRCCS Istituto Giannina Gaslini, Genova, Italy
| | - Ramona Cordani
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics and Maternal and Child Health (DINOGMI), University of Genova, Genova, Italy
- Unit of Child Neuropsychiatry, IRCCS Istituto Giannina Gaslini, Genova, Italy
| | - Irene Bagnasco
- Division of Child Neuropsychiatry, Martini Hospital, Torino, Italy
| | - Fabiana Vercellino
- Child Neuropsychiatry Unit, SS Antonio e Biagio e Cesare Arrigo Hospital, Alessandria, Italy
| | - Lucio Giordano
- Child Neuropsychiatric Unit, Civilian Hospital, Brescia, Italy
| | - Giuseppe Milito
- Child Neuropsychiatric Unit, Civilian Hospital, Brescia, Italy
| | - Giovanni Battista Ferrero
- Department of Clinical and Biological Sciences, School of Medicine, University of Turin, Turin, Italy
| | - Giorgia Mandrile
- Department of Clinical and Biological Sciences, School of Medicine, University of Turin, Turin, Italy
| | - Marcello Scala
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics and Maternal and Child Health (DINOGMI), University of Genova, Genova, Italy
- Pediatric Neurology and Muscular Diseases Unit, IRCCS Istituto Giannina Gaslini, Genova, Italy
| | - Mariaclaudia Meli
- Division of Paediatric Neurology, Department of Paediatrics, University of Catania, Catania, Italy
| | - Raffaele Falsaperla
- Neonatal Intensive Care Unit, San Marco Hospital, University Hospital Policlinico "G. Rodolico-San Marco," Catania, Italy
- Unit of Pediatrics and Pediatric Emergency, University Hospital Policlinico "G. Rodolico-San Marco," Catania, Italy
| | | | - Elisa De Grandis
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics and Maternal and Child Health (DINOGMI), University of Genova, Genova, Italy
- Unit of Child Neuropsychiatry, IRCCS Istituto Giannina Gaslini, Genova, Italy
| | - Edoardo Canale
- Unit of Child Neuropsychiatry, IRCCS Istituto Giannina Gaslini, Genova, Italy
| | - Elisabetta Amadori
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics and Maternal and Child Health (DINOGMI), University of Genova, Genova, Italy
- Pediatric Neurology and Muscular Diseases Unit, IRCCS Istituto Giannina Gaslini, Genova, Italy
| | - Pasquale Striano
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics and Maternal and Child Health (DINOGMI), University of Genova, Genova, Italy
- Pediatric Neurology and Muscular Diseases Unit, IRCCS Istituto Giannina Gaslini, Genova, Italy
| | - Lino Nobili
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics and Maternal and Child Health (DINOGMI), University of Genova, Genova, Italy
- Unit of Child Neuropsychiatry, IRCCS Istituto Giannina Gaslini, Genova, Italy
| | - Laura Siri
- Unit of Child Neuropsychiatry, IRCCS Istituto Giannina Gaslini, Genova, Italy
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Karlak V, Jankowski J, Kolasińska J, Nijakowski K. Kleefstra Syndrome-Dental Manifestations and Needs: A Case Report with a Literature Review. Case Rep Dent 2023; 2023:2478465. [PMID: 37780946 PMCID: PMC10541297 DOI: 10.1155/2023/2478465] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Revised: 09/12/2023] [Accepted: 09/14/2023] [Indexed: 10/03/2023] Open
Abstract
Kleefstra syndrome (KS) is a rare genetic disorder (prevalence < 1/1 000 000) characterised by autistic spectrum disorder (ASD), childhood hypotonia, and seizures. A typical facial appearance includes microcephaly, arched eyebrows, synophrism, hypertelorism, a short nose, midface hypoplasia, prognathism, and tongue protrusion. This case report presents a 19-year-old female with KS from a dentist's perspective. The patient demonstrates limited mouth opening with a slight deviation of the mandible on the left side. The mandibular prognathism and anterior open bite are visible. A generalised inflammatory gingival enlargement is most likely a response to local irritants like plaque and calculus but is enhanced by the patient's mouth breathing habit. Also, the tongue is unusually large-macroglossia. Dental anomalies were diagnosed by digital panoramic radiograph, including dilaceration of the maxillary left second premolar and taurodontism. The patient was qualified to be treated under general anaesthesia with multiple extractions, restorations, hygienisation procedures, and tooth remineralisation. This individual should also be considered for orthodontic treatment and an eventual tongue reduction procedure. In the case of KS, multidisciplinary cooperation as well as frequent dental check-ups with fluoride prophylaxis are recommended. Unfortunately, dental treatment is still not an integral part of taking care of disabled children and youth with rare diseases.
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Affiliation(s)
- Victoria Karlak
- University Centre of Dentistry and Specialised Medicine, 60-812 Poznan, Poland
| | - Jakub Jankowski
- Student's Scientific Group in Department of Conservative Dentistry and Endodontics, Poznan University of Medical Sciences, 60-812 Poznan, Poland
| | - Julia Kolasińska
- Student's Scientific Group in Department of Conservative Dentistry and Endodontics, Poznan University of Medical Sciences, 60-812 Poznan, Poland
| | - Kacper Nijakowski
- Department of Conservative Dentistry and Endodontics, Poznan University of Medical Sciences, 60-812 Poznan, Poland
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3
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Frisk S, Wachtmeister A, Laurell T, Lindstrand A, Jäntti N, Malmgren H, Lagerstedt-Robinson K, Tesi B, Taylan F, Nordgren A. Detection of germline mosaicism in fathers of children with intellectual disability syndromes caused by de novo variants. Mol Genet Genomic Med 2022; 10:e1880. [PMID: 35118825 PMCID: PMC9000944 DOI: 10.1002/mgg3.1880] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Revised: 12/21/2021] [Accepted: 01/14/2022] [Indexed: 12/03/2022] Open
Abstract
Background De novo variants are a common cause to rare intellectual disability syndromes, associated with low recurrence risk. However, when such variants occur pre‐zygotically in parental germ cells, the recurrence risk might be higher. Still, the recurrence risk estimates are mainly based on empirical data and the prevalence of germline mosaicism is often unknown. Methods To establish the prevalence of mosaicism in parents of children with intellectual disability syndromes caused by de novo variants, we performed droplet digital PCR on DNA extracted from blood (43 trios), and sperm (31 fathers). Results We detected low‐level mosaicism in sperm‐derived DNA but not in blood in the father of a child with Kleefstra syndrome caused by an EHMT1 variant. Additionally, we found a higher level of paternal mosaicism in sperm compared to blood in the father of a child with Gillespie syndrome caused by an ITPR1 variant. Conclusion By employing droplet digital PCR, we detected paternal germline mosaicism in two intellectual disability syndromes. In both cases, the mosaicism level was higher in sperm than blood, indicating that analysis of blood alone may underestimate germline mosaicism. Therefore, sperm analysis can be clinically useful to establish the recurrence risk for parents and improve genetic counselling.
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Affiliation(s)
- Sofia Frisk
- Department of Molecular Medicine and Surgery, Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden.,Department of Clinical Genetics, Karolinska University Laboratory, Karolinska University Hospital, Stockholm, Sweden
| | - Alexandra Wachtmeister
- Department of Molecular Medicine and Surgery, Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Tobias Laurell
- Department of Molecular Medicine and Surgery, Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden.,Department of Hand Surgery, Södersjukhuset, Stockholm, Sweden
| | - Anna Lindstrand
- Department of Molecular Medicine and Surgery, Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden.,Department of Clinical Genetics, Karolinska University Laboratory, Karolinska University Hospital, Stockholm, Sweden
| | - Nina Jäntti
- Department of Molecular Medicine and Surgery, Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden.,Department of Clinical Genetics, Karolinska University Laboratory, Karolinska University Hospital, Stockholm, Sweden
| | - Helena Malmgren
- Department of Molecular Medicine and Surgery, Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden.,Department of Clinical Genetics, Karolinska University Laboratory, Karolinska University Hospital, Stockholm, Sweden
| | - Kristina Lagerstedt-Robinson
- Department of Molecular Medicine and Surgery, Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden.,Department of Clinical Genetics, Karolinska University Laboratory, Karolinska University Hospital, Stockholm, Sweden
| | - Bianca Tesi
- Department of Molecular Medicine and Surgery, Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden.,Department of Clinical Genetics, Karolinska University Laboratory, Karolinska University Hospital, Stockholm, Sweden
| | - Fulya Taylan
- Department of Molecular Medicine and Surgery, Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden.,Department of Clinical Genetics, Karolinska University Laboratory, Karolinska University Hospital, Stockholm, Sweden
| | - Ann Nordgren
- Department of Molecular Medicine and Surgery, Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden.,Department of Clinical Genetics, Karolinska University Laboratory, Karolinska University Hospital, Stockholm, Sweden
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4
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Jobic F, Lacot-Leriche E, Piton A, Le Moing AG, Mathieu-Dramard M, Costantini S, Morin G, Jedraszak G. Kleefstra syndrome: Recurrence in siblings due to a paternal mosaic mutation. Am J Med Genet A 2021; 185:3877-3883. [PMID: 34357686 DOI: 10.1002/ajmg.a.62448] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Revised: 06/21/2021] [Accepted: 07/03/2021] [Indexed: 11/06/2022]
Abstract
Kleefstra syndrome (KS) is a rare autosomic dominant genetic disorder caused by euchromatic histone methyltransferase 1 (EHMT1) alterations. Patients mainly present with moderate to severe intellectual disability, a severe delay in/or absence of speech, autism spectrum disorder, childhood hypotonia, neuropsychiatric anomalies, and distinctive dysmorphic features. Here, we report the cases of a male and a female, two younger siblings of three, with asymptomatic parents. An EHMT1 new mutation was identified. Both presented with a typical core phenotype. Some specific features were noted, such as macrocephaly (previously reported) and enuresis (not yet described). Parental analysis identified the mutation in the mosaic state in the father. Reverse phenotyping enabled us to highlight the pauci phenotype features of inguinal hernia, azoospermia, and possible behavioral disorders. This allowed us to adapt his follow-up and genetic counseling for the family. Our three reported cases provide a new description of KS with an intragenic EHMT1 mutation, whereas in the literature most reported cases have EHMT1 deletions. Moreover, in the areas of next-generation sequencing and trio techniques with parental segregation, it is important to remain cautious about disregarding variants based on an autosomal recessive hypothesis.
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Affiliation(s)
- Florence Jobic
- Reference Center for Rare Diseases, Amiens-Picardy University Hospital, Amiens, France
| | - Emilie Lacot-Leriche
- Reference Center for Rare Diseases, Amiens-Picardy University Hospital, Amiens, France.,EA 7273 CRP-CPO, University of Picardy, Jules Verne, Amiens, France
| | - Amélie Piton
- Laboratory of Genetic Diagnosis, Institut de Génétique Médicale d'Alsace, Hôpitaux Universitaires de Strasbourg, Strasbourg, France
| | - Anne-Gaëlle Le Moing
- Department of Child Neurology, Amiens-Picardy University Hospital, Amiens, France
| | | | - Sara Costantini
- Reference Center for Rare Diseases, Amiens-Picardy University Hospital, Amiens, France
| | - Gilles Morin
- Genetics Laboratory, Amiens-Picardy University Hospital, Amiens, France
| | - Guillaume Jedraszak
- Genetics Laboratory, Amiens-Picardy University Hospital, Amiens, France.,EA 4666 HEMATIM - CURS, University of Picardy, Jules Verne, Amiens, France
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5
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Drakulic D, Djurovic S, Syed YA, Trattaro S, Caporale N, Falk A, Ofir R, Heine VM, Chawner SJRA, Rodriguez-Moreno A, van den Bree MBM, Testa G, Petrakis S, Harwood AJ. Copy number variants (CNVs): a powerful tool for iPSC-based modelling of ASD. Mol Autism 2020; 11:42. [PMID: 32487215 PMCID: PMC7268297 DOI: 10.1186/s13229-020-00343-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Accepted: 05/04/2020] [Indexed: 02/06/2023] Open
Abstract
Patients diagnosed with chromosome microdeletions or duplications, known as copy number variants (CNVs), present a unique opportunity to investigate the relationship between patient genotype and cell phenotype. CNVs have high genetic penetrance and give a good correlation between gene locus and patient clinical phenotype. This is especially effective for the study of patients with neurodevelopmental disorders (NDD), including those falling within the autism spectrum disorders (ASD). A key question is whether this correlation between genetics and clinical presentation at the level of the patient can be translated to the cell phenotypes arising from the neurodevelopment of patient induced pluripotent stem cells (iPSCs).Here, we examine how iPSCs derived from ASD patients with an associated CNV inform our understanding of the genetic and biological mechanisms underlying the aetiology of ASD. We consider selection of genetically characterised patient iPSCs; use of appropriate control lines; aspects of human neurocellular biology that can capture in vitro the patient clinical phenotype; and current limitations of patient iPSC-based studies. Finally, we consider how future research may be enhanced to maximise the utility of CNV patients for research of pathological mechanisms or therapeutic targets.
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Affiliation(s)
- Danijela Drakulic
- Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, 11042 Belgrade, 152, Serbia
| | - Srdjan Djurovic
- Department of Medical Genetics, Oslo University Hospital, 0424, Oslo, Norway
- NORMENT, Department of Clinical Science, University of Bergen, 5007, Bergen, Norway
| | - Yasir Ahmed Syed
- Neuroscience & Mental Health Research Institute, Cardiff University, Cardiff, CF24 4HQ, UK
| | - Sebastiano Trattaro
- Laboratory of Stem Cell Epigenetics, IEO, European Institute of Oncology, IRCCS, 20146, Milan, Italy
- Department of Oncology and Hemato-oncology, University of Milan, 20122, Milan, Italy
| | - Nicolò Caporale
- Laboratory of Stem Cell Epigenetics, IEO, European Institute of Oncology, IRCCS, 20146, Milan, Italy
- Department of Oncology and Hemato-oncology, University of Milan, 20122, Milan, Italy
| | - Anna Falk
- Department of Neuroscience, Karolinska Institutet, 17177, Stockholm, Sweden
| | - Rivka Ofir
- BGU-iPSC Core Facility, The Regenerative Medicine & Stem Cell (RMSC) Research Center, Ben Gurion University of the Negev, 84105, Beer-Sheva, Israel
| | - Vivi M Heine
- Complex Trait Genetics, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
- Child and Youth Psychiatry, Emma Children's Hospital, Amsterdam UMC, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, 1081, Amsterdam, The Netherlands
| | - Samuel J R A Chawner
- Neuroscience & Mental Health Research Institute, Cardiff University, Cardiff, CF24 4HQ, UK
- MRC Centre for Neuropsychiatric Genetics and Genomics, Cardiff University, Cardiff, CF24 4HQ, UK
| | - Antonio Rodriguez-Moreno
- Department of Physiology, Anatomy and Cell Biology, University Pablo de Olavide, Ctra. de Utrera, Km 1, 41013, Seville, Spain
| | - Marianne B M van den Bree
- Neuroscience & Mental Health Research Institute, Cardiff University, Cardiff, CF24 4HQ, UK
- MRC Centre for Neuropsychiatric Genetics and Genomics, Cardiff University, Cardiff, CF24 4HQ, UK
| | - Giuseppe Testa
- Laboratory of Stem Cell Epigenetics, IEO, European Institute of Oncology, IRCCS, 20146, Milan, Italy
- Department of Oncology and Hemato-oncology, University of Milan, 20122, Milan, Italy
- Human Technopole, Via Cristina Belgioioso 171, 20157, Milan, Italy
| | - Spyros Petrakis
- Institute of Applied Biosciences/Centre for Research and Technology Hellas, 57001, Thessaloniki, Greece.
| | - Adrian J Harwood
- Neuroscience & Mental Health Research Institute, Cardiff University, Cardiff, CF24 4HQ, UK.
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6
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SATB2-associated syndrome: first report of a gonadal and somatic mosaicism for an intragenic copy number variation. Clin Dysmorphol 2020; 28:205-210. [PMID: 31425298 DOI: 10.1097/mcd.0000000000000293] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Gonadal mosaicism has been reported in a variety of dominant or X-linked conditions and should be considered in all cases of apparent de-novo variation. Recently, some cases of supposed parental germline mosaicism have been shown to result from low-level somatic mosaicism. In most of the cases, mosaicism has been reported for pathogenic single nucleotide variants with only a few cases of copy number variation mosaicism described so far. Herein, we present the first case of parental somatic and gonadal copy number variation mosaicism in the SATB2 gene. We report three brothers presenting with the SATB2-associated syndrome. They all carry the same 121-kb heterozygous intragenic deletion of SATB2. Parental somatic mosaicism was detected by array-comparative genomic hybridization on a maternal blood sample and confirmed by Fluorescence in situ hybridization analysis on blood and buccal cells. This clinical report highlights the importance of investigating for parental somatic mosaicism to estimate the proper recurrence risk for subsequent pregnancy.
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7
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Neuronal network dysfunction in a model for Kleefstra syndrome mediated by enhanced NMDAR signaling. Nat Commun 2019; 10:4928. [PMID: 31666522 PMCID: PMC6821803 DOI: 10.1038/s41467-019-12947-3] [Citation(s) in RCA: 66] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Accepted: 10/10/2019] [Indexed: 12/24/2022] Open
Abstract
Kleefstra syndrome (KS) is a neurodevelopmental disorder caused by mutations in the histone methyltransferase EHMT1. To study the impact of decreased EHMT1 function in human cells, we generated excitatory cortical neurons from induced pluripotent stem (iPS) cells derived from KS patients. Neuronal networks of patient-derived cells exhibit network bursting with a reduced rate, longer duration, and increased temporal irregularity compared to control networks. We show that these changes are mediated by upregulation of NMDA receptor (NMDAR) subunit 1 correlating with reduced deposition of the repressive H3K9me2 mark, the catalytic product of EHMT1, at the GRIN1 promoter. In mice EHMT1 deficiency leads to similar neuronal network impairments with increased NMDAR function. Finally, we rescue the KS patient-derived neuronal network phenotypes by pharmacological inhibition of NMDARs. Summarized, we demonstrate a direct link between EHMT1 deficiency and NMDAR hyperfunction in human neurons, providing a potential basis for more targeted therapeutic approaches for KS.
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8
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Ciaccio C, Scuvera G, Tucci A, Gentilin B, Baccarin M, Marchisio P, Avignone S, Milani D. New Insights into Kleefstra Syndrome: Report of Two Novel Cases with Previously Unreported Features and Literature Review. Cytogenet Genome Res 2018; 156:127-133. [DOI: 10.1159/000494532] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/23/2018] [Indexed: 11/19/2022] Open
Abstract
Kleefstra syndrome (KS) is a rare genetic condition resulting from either 9q34.3 microdeletions or mutations in the EHMT1 gene located in the same genomic region. To date, approximately 100 patients have been reported, thereby allowing the core phenotype of KS to be defined as developmental delay/intellectual disability, generalized hypotonia, neuropsychiatric anomalies, and a distinctive facial appearance. Here, to further expand the knowledge on genotype and phenotype of this condition, we report 2 novel cases: one patient carrying a 46-kb 9q34.3 deletion and showing macrocephaly never described in KS, and a second patient carrying a classic 9q34.3 deletion, presenting with a previously unreported skeletal feature (postaxial polydactyly of the right foot) and an unusual brain anomaly (olfactory bulb hypoplasia) observed via magnetic resonance imaging. Further, we provide a review of the current literature regarding KS and compare these 2 patients with those previously described, thereby confirming that the genotype-phenotype correlation in KS remains difficult to determine.
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9
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de Boer A, Vermeulen K, Egger JIM, Janzing JGE, de Leeuw N, Veenstra-Knol HE, den Hollander NS, van Bokhoven H, Staal W, Kleefstra T. EHMT1 mosaicism in apparently unaffected parents is associated with autism spectrum disorder and neurocognitive dysfunction. Mol Autism 2018; 9:5. [PMID: 29416845 PMCID: PMC5784506 DOI: 10.1186/s13229-018-0193-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2017] [Accepted: 01/16/2018] [Indexed: 02/06/2023] Open
Abstract
Background Genetic mosaicism is only detected occasionally when there are no obvious health or developmental issues. Most cases concern healthy parents in whom mosaicism is identified upon targeted testing of a genetic defect that was initially detected in their children. A germline genetic defect affecting the euchromatin histone methyltransferase 1 (EHMT1) gene causes Kleefstra syndrome, which is associated with the typical triad of distinct facial appearance, (childhood) hypotonia, and intellectual disability. A high degree of psychopathology is associated with this syndrome. A few parents with a mosaic EHMT1 mutation have been detected upon testing after a child was diagnosed with a germline EHMT1 defect. At first glance, carriers of a mosaic EHMT1 mutation appeared to function normally. However, recent studies have shown that de novo, postzygotic mutations in important developmental genes significantly contribute to autism spectrum disorder (ASD). Therefore, we hypothesized that EHMT1 mosaicism could cause neuropsychiatric defects. To investigate this, we performed a detailed investigation of cognitive neuropsychiatric parameters in parents identified with EHMT1 mosaicism. Methods Three adults (two males, one female) with a genetically confirmed diagnosis of EHMT1 mosaicism were examined by means of a battery of tests and observational instruments covering both neurocognitive and psychiatric features. The battery included the following instruments: the Autism Diagnostic Observation Schedule (ADOS), the mini Psychiatric Assessment Schedules for Adults with Developmental Disabilities (mini PAS-ADD), the Vineland Adaptive Behavior Scales (VABS), and the Cambridge Neuropsychological Test Automated Battery (CANTAB). These measures were compared with our previously reported data from Kleefstra syndrome patients with confirmed (germline) EHMT1 defects. Results All three subjects achieved maximum total scores on the VABS, indicative of adequate (adaptive) functioning. In all, scores above cutoff were found on the ADOS for ASD and on the mini PAS-ADD for major depressive disorder (lifetime). Finally, results on the CANTAB showed impaired cognitive flexibility in all subjects. Conclusion Individuals with EHMT1 mosaicism seem to have increased vulnerability for developing severe psychopathology, especially ASD and mood disorders. Although at first glance they appear to be well-adapted in their daily functioning, they may experience significant psychiatric symptoms and show reduced cognitive flexibility in comparison to the general population.
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Affiliation(s)
- Anneke de Boer
- 1Karakter Child and Adolescent Psychiatry University Centre, Nijmegen, the Netherlands.,3Department of Psychiatry, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Karlijn Vermeulen
- 1Karakter Child and Adolescent Psychiatry University Centre, Nijmegen, the Netherlands.,2Donders Institute for Brain, Cognition and Behavior, Centre for Neuroscience, Radboud University, Nijmegen, the Netherlands.,3Department of Psychiatry, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Jos I M Egger
- 4Centre of Excellence for Neuropsychiatry, Vincent van Gogh Institute for Psychiatry, Venray, the Netherlands.,5Behavioural Science Institute, Radboud University, Nijmegen, the Netherlands.,6Donders Institute for Brain, Cognition and Behaviour, Centre for Cognition, Radboud University, Nijmegen, the Netherlands
| | - Joost G E Janzing
- 3Department of Psychiatry, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Nicole de Leeuw
- 7Department of Human Genetics, Radboud University Medical Center, P.O. Box 9101, 6500 HB Nijmegen, the Netherlands
| | - Hermine E Veenstra-Knol
- 8Department of Genetics, University Medical Centre Groningen, University of Groningen, Groningen, the Netherlands
| | | | - Hans van Bokhoven
- 2Donders Institute for Brain, Cognition and Behavior, Centre for Neuroscience, Radboud University, Nijmegen, the Netherlands.,7Department of Human Genetics, Radboud University Medical Center, P.O. Box 9101, 6500 HB Nijmegen, the Netherlands
| | - Wouter Staal
- 1Karakter Child and Adolescent Psychiatry University Centre, Nijmegen, the Netherlands.,2Donders Institute for Brain, Cognition and Behavior, Centre for Neuroscience, Radboud University, Nijmegen, the Netherlands.,3Department of Psychiatry, Radboud University Medical Center, Nijmegen, the Netherlands.,10Faculty of Social Sciences, Leiden University, Leiden, the Netherlands.,11Leiden Institute for Brain and Cognition, Leiden University, Leiden, the Netherlands
| | - Tjitske Kleefstra
- 2Donders Institute for Brain, Cognition and Behavior, Centre for Neuroscience, Radboud University, Nijmegen, the Netherlands.,7Department of Human Genetics, Radboud University Medical Center, P.O. Box 9101, 6500 HB Nijmegen, the Netherlands
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10
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Blackburn PR, Tischer A, Zimmermann MT, Kemppainen JL, Sastry S, Knight Johnson AE, Cousin MA, Boczek NJ, Oliver G, Misra VK, Gavrilova RH, Lomberk G, Auton M, Urrutia R, Klee EW. A Novel Kleefstra Syndrome-associated Variant That Affects the Conserved TPL X Motif within the Ankyrin Repeat of EHMT1 Leads to Abnormal Protein Folding. J Biol Chem 2017; 292:3866-3876. [PMID: 28057753 PMCID: PMC5339767 DOI: 10.1074/jbc.m116.770545] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2016] [Revised: 01/05/2017] [Indexed: 12/26/2022] Open
Abstract
Kleefstra syndrome (KS) (Mendelian Inheritance in Man (MIM) no. 610253), also known as 9q34 deletion syndrome, is an autosomal dominant disorder caused by haploinsufficiency of euchromatic histone methyltransferase-1 (EHMT1). The clinical phenotype of KS includes moderate to severe intellectual disability with absent speech, hypotonia, brachycephaly, congenital heart defects, and dysmorphic facial features with hypertelorism, synophrys, macroglossia, protruding tongue, and prognathism. Only a few cases of de novo missense mutations in EHMT1 giving rise to KS have been described. However, some EHMT1 variants have been described in individuals presenting with autism spectrum disorder or mild intellectual disability, suggesting that the phenotypic spectrum resulting from EHMT1 alterations may be quite broad. In this report, we describe two unrelated patients with complex medical histories consistent with KS in whom next generation sequencing identified the same novel c.2426C>T (p.P809L) missense variant in EHMT1. To examine the functional significance of this novel variant, we performed molecular dynamics simulations of the wild type and p.P809L variant, which predicted that the latter would have a propensity to misfold, leading to abnormal histone mark binding. Recombinant EHMT1 p.P809L was also studied using far UV circular dichroism spectroscopy and intrinsic protein fluorescence. These functional studies confirmed the model-based hypotheses and provided evidence for protein misfolding and aberrant target recognition as the underlying pathogenic mechanism for this novel KS-associated variant. This is the first report to suggest that missense variants in EHMT1 that lead to protein misfolding and disrupted histone mark binding can lead to KS.
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Affiliation(s)
- Patrick R Blackburn
- From the Center for Individualized Medicine and.,the Department of Health Science Research, Mayo Clinic, Jacksonville, Florida 32224
| | - Alexander Tischer
- the Division of Hematology, Departments of Internal Medicine and Biochemistry and Molecular Biology
| | - Michael T Zimmermann
- the Department of Health Science Research, Division of Biomedical Statistics and Informatics
| | | | - Sujatha Sastry
- the Department of Pediatrics, Division of Genetics and Metabolic Disorders, Wayne State University School of Medicine, Detroit, Michigan 48201, and
| | - Amy E Knight Johnson
- the Department of Human Genetics, University of Chicago, Chicago, Illinois 60637
| | - Margot A Cousin
- the Center for Individualized Medicine.,the Department of Health Science Research
| | - Nicole J Boczek
- the Center for Individualized Medicine.,the Department of Health Science Research
| | | | - Vinod K Misra
- the Department of Pediatrics, Division of Genetics and Metabolic Disorders, Wayne State University School of Medicine, Detroit, Michigan 48201, and
| | | | - Gwen Lomberk
- the Laboratory of Epigenetics and Chromatin Dynamics, Epigenomics Translational Program, Center for Individualized Medicine, Mayo Clinic, Rochester, Minnesota 55905
| | - Matthew Auton
- the Division of Hematology, Departments of Internal Medicine and Biochemistry and Molecular Biology
| | - Raul Urrutia
- the Laboratory of Epigenetics and Chromatin Dynamics, Epigenomics Translational Program, Center for Individualized Medicine, Mayo Clinic, Rochester, Minnesota 55905,
| | - Eric W Klee
- the Department of Clinical Genomics, .,the Center for Individualized Medicine.,the Department of Health Science Research
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11
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de Leeuw N, Dijkhuizen T, Hehir-Kwa JY, Carter NP, Feuk L, Firth HV, Kuhn RM, Ledbetter DH, Martin CL, van Ravenswaaij-Arts CMA, Scherer SW, Shams S, Van Vooren S, Sijmons R, Swertz M, Hastings R. Diagnostic interpretation of array data using public databases and internet sources. Hum Mutat 2016; 33:930-40. [PMID: 26285306 DOI: 10.1002/humu.22049] [Citation(s) in RCA: 77] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The range of commercially available array platforms and analysis software packages is expanding and their utility is improving, making reliable detection of copy-number variants (CNVs) relatively straightforward. Reliable interpretation of CNV data, however, is often difficult and requires expertise. With our knowledge of the human genome growing rapidly, applications for array testing continuously broadening, and the resolution of CNV detection increasing, this leads to great complexity in interpreting what can be daunting data. Correct CNV interpretation and optimal use of the genotype information provided by single-nucleotide polymorphism probes on an array depends largely on knowledge present in various resources. In addition to the availability of host laboratories' own datasets and national registries, there are several public databases and Internet resources with genotype and phenotype information that can be used for array data interpretation. With so many resources now available, it is important to know which are fit-for-purpose in a diagnostic setting. We summarize the characteristics of the most commonly used Internet databases and resources, and propose a general data interpretation strategy that can be used for comparative hybridization, comparative intensity, and genotype-based array data.
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Affiliation(s)
- Nicole de Leeuw
- Department of Human Genetics, Radboud University Nijmegen Medical Centre, Nijmegen, the Netherlands
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12
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Martín-De Saro MD, Valdés-Miranda JM, Plaza-Benhumea L, Pérez-Cabrera A, Gonzalez-Huerta LM, Guevara-Yañez R, Cuevas-Covarrubias SA. Characterization of a Complex Chromosomal Rearrangement Involving a de novo Duplication of 9p and 9q and a Deletion of 9q. Cytogenet Genome Res 2016; 147:124-9. [PMID: 26900692 DOI: 10.1159/000444138] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/26/2015] [Indexed: 11/19/2022] Open
Abstract
Rearrangements of the distal region of 9p are important chromosome imbalances in human beings. Trisomy 9p is the fourth most frequent chromosome anomaly and is a clinically recognizable syndrome. Kleefstra syndrome, previously named 9q subtelomeric deletion syndrome, is either caused by a submicroscopic deletion in 9q34.3 or an intragenic mutation of EHMT1. We report a Mexican male patient with abnormal development, dysmorphism, systemic anomalies and a complex chromosomal rearrangement (CCR). GTG-banding revealed a 46,XY,add(9)(q34.3) karyotype, whereas array analysis resulted in arr[hg19] 9p24.3p23(203,861-11,842,172)×3, 9q34.3(138,959,881-139,753,294)×3, 9q34.3(139,784,913-141,020,389)×1. Array and karyotype analyses were normal in both parents. Partial duplication of 9p is one of the most commonly detected autosomal structural abnormalities in liveborn infants. A microdeletion in 9q34.3 corresponds to Kleefstra syndrome, whereas a microduplication in 9q34.3 shows a great clinical variability. Here, we present a CCR in a patient with multiple congenital anomalies who represents the first case with partial 9p trisomy, partial 9q trisomy and partial 9q monosomy.
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13
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Samango-Sprouse C, Lawson P, Sprouse C, Stapleton E, Sadeghin T, Gropman A. Expanding the phenotypic profile of Kleefstra syndrome: A female with low-average intelligence and childhood apraxia of speech. Am J Med Genet A 2016; 170A:1312-6. [PMID: 26833960 DOI: 10.1002/ajmg.a.37575] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2014] [Accepted: 01/08/2016] [Indexed: 11/09/2022]
Abstract
Kleefstra syndrome (KS) is a rare neurogenetic disorder most commonly caused by deletion in the 9q34.3 chromosomal region and is associated with intellectual disabilities, severe speech delay, and motor planning deficits. To our knowledge, this is the first patient (PQ, a 6-year-old female) with a 9q34.3 deletion who has near normal intelligence, and developmental dyspraxia with childhood apraxia of speech (CAS). At 6, the Wechsler Preschool and Primary Intelligence testing (WPPSI-III) revealed a Verbal IQ of 81 and Performance IQ of 79. The Beery Buktenica Test of Visual Motor Integration, 5th Edition (VMI) indicated severe visual motor deficits: VMI = 51; Visual Perception = 48; Motor Coordination < 45. On the Receptive One Word Picture Vocabulary Test-R (ROWPVT-R), she had standard scores of 96 and 99 in contrast to an Expressive One Word Picture Vocabulary-R (EOWPVT-R) standard scores of 73 and 82, revealing a discrepancy in vocabulary domains on both evaluations. Preschool Language Scale-4 (PLS-4) on PQ's first evaluation reveals a significant difference between auditory comprehension and expressive communication with standard scores of 78 and 57, respectively, further supporting the presence of CAS. This patient's near normal intelligence expands the phenotypic profile as well as the prognosis associated with KS. The identification of CAS in this patient provides a novel explanation for the previously reported speech delay and expressive language disorder. Further research is warranted on the impact of CAS on intelligence and behavioral outcome in KS. Therapeutic and prognostic implications are discussed.
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Affiliation(s)
- Carole Samango-Sprouse
- Neurodevelopmental Diagnostic Center for Young Children, Crofton, Maryland.,The Focus Foundation, Davidsonville, Maryland.,Department of Pediatrics, George Washington University, Washington, District of Columbia.,Department of Human and Molecular Genetics, Florida International University, Miami, Florida
| | | | - Courtney Sprouse
- Department of Neurology, Children's National Medical Center, Washington, District of Columbia
| | | | - Teresa Sadeghin
- Neurodevelopmental Diagnostic Center for Young Children, Crofton, Maryland.,The Focus Foundation, Davidsonville, Maryland
| | - Andrea Gropman
- Department of Neurology, Children's National Medical Center, Washington, District of Columbia.,George Washington University of the Health Sciences, Washington, District of Columbia
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14
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Hervé B, Roume J, Cognard S, Fauvert D, Molina-Gomes D, Vialard F. Low-level mosaicism of a de novo derivative chromosome 9 from a t(5;9)(q35.1;q34.3) has a major phenotypic impact. Eur J Med Genet 2015; 58:346-50. [DOI: 10.1016/j.ejmg.2015.04.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2014] [Accepted: 04/26/2015] [Indexed: 02/01/2023]
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15
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Penacho V, Galán F, Martín-Bayón TA, Mayo S, Manchón I, Carrasco A, Martínez-Castellano F, Alcaraz LA. Prenatal Diagnosis of a Female Fetus with Ring Chromosome 9, 46,XX,r(9)(p24q34), and a de novo Interstitial 9p Deletion. Cytogenet Genome Res 2015; 144:275-9. [DOI: 10.1159/000370256] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/17/2014] [Indexed: 11/19/2022] Open
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16
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Boutry-Kryza N, Labalme A, Ville D, de Bellescize J, Touraine R, Prieur F, Dimassi S, Poulat AL, Till M, Rossi M, Bourel-Ponchel E, Delignières A, Le Moing AG, Rivier C, des Portes V, Edery P, Calender A, Sanlaville D, Lesca G. Molecular characterization of a cohort of 73 patients with infantile spasms syndrome. Eur J Med Genet 2014; 58:51-8. [PMID: 25497044 DOI: 10.1016/j.ejmg.2014.11.007] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2014] [Accepted: 11/30/2014] [Indexed: 01/10/2023]
Abstract
Infantile Spasms syndrome (ISs) is a characterized by epileptic spasms occurring in clusters with an onset in the first year of life. West syndrome represents a subset of ISs that associates spasms in clusters, a hypsarrhythmia EEG pattern and a developmental arrest or regression. Aetiology of ISs is widely heterogeneous including many genetic causes. Many patients, however, remain without etiological diagnosis, which is critical for prognostic purpose and genetic counselling. In the present study, we performed genetic screening of 73 patients with different types of ISs by array-CGH and molecular analysis of 5 genes: CDKL5, STXBP1, KCNQ2, and GRIN2A, whose mutations cause different types of epileptic encephalopathies, including ISs, as well as MAGI2, which was suggested to be related to a subset of ISs. In total, we found a disease-causing mutation or CNV (Copy Number Variation) in 15% of the patients. These included 6 point mutations found in CDKL5 (n = 3) and STXBP1 (n = 3), 3 microdeletions (10 Mb in 2q24.3, 3.2 Mb in 5q14.3 including the region upstream to MEF2C, and 256 kb in 9q34 disrupting EHMT1), and 2 microduplications (671 kb in 2q24.3 encompassing SCN2A, and 11.93 Mb in Xq28). In addition, we discuss 3 CNVs as potential risk factors, including one 16p12.1 deletion, one intronic deletion of the NEDD4 gene, and one intronic deletion of CALN1 gene. The present findings highlight the efficacy of combined cytogenetic and targeted mutation screening to improve the diagnostic yield in patient with ISs.
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Affiliation(s)
- Nadia Boutry-Kryza
- Department of Molecular Genetics, Lyon University Hospital, Lyon, France; CRNL, CNRS UMR 5292, INSERM U1028, Lyon, France
| | - Audrey Labalme
- Department of Genetics, Lyon University Hospital, Lyon, France
| | - Dorothee Ville
- Reference Center for Tuberous Sclerosis and Rare Epileptic Syndromes, Lyon University Hospital, Lyon, France
| | - Julitta de Bellescize
- Epilepsy, Sleep and Pediatric Neurophysiology Department, Lyon University Hospital, Lyon, France
| | - Renaud Touraine
- Department of Genetics, Hospital Nord, Saint-Etienne University Hospital, France
| | - Fabienne Prieur
- Department of Genetics, Hospital Nord, Saint-Etienne University Hospital, France
| | - Sarra Dimassi
- CRNL, CNRS UMR 5292, INSERM U1028, Lyon, France; Department of Genetics, Lyon University Hospital, Lyon, France; Claude Bernard Lyon I University, Lyon, France
| | - Anne-Lise Poulat
- Reference Center for Tuberous Sclerosis and Rare Epileptic Syndromes, Lyon University Hospital, Lyon, France
| | - Marianne Till
- Department of Genetics, Lyon University Hospital, Lyon, France
| | - Massimiliano Rossi
- CRNL, CNRS UMR 5292, INSERM U1028, Lyon, France; Department of Genetics, Lyon University Hospital, Lyon, France
| | - Emilie Bourel-Ponchel
- Pediatric Functional Exploration of the Nervous System Service, Hospital Nord, Amiens University Hospital, Amiens, France
| | - Aline Delignières
- Department of Neurology, Hospital Nord, Amiens University Hospital, Amiens, France
| | - Anne-Gaelle Le Moing
- Department of Neurology, Hospital Nord, Amiens University Hospital, Amiens, France
| | - Clotilde Rivier
- Department of Pediatrics, Hospital Nord-Ouest, Villefranche sur Saone, France
| | - Vincent des Portes
- Reference Center for Tuberous Sclerosis and Rare Epileptic Syndromes, Lyon University Hospital, Lyon, France; Claude Bernard Lyon I University, Lyon, France; CNRS UMR 5403, Institut des Sciences Cognitives, L2C2, Bron, France
| | - Patrick Edery
- CRNL, CNRS UMR 5292, INSERM U1028, Lyon, France; Department of Genetics, Lyon University Hospital, Lyon, France; Claude Bernard Lyon I University, Lyon, France
| | - Alain Calender
- Department of Molecular Genetics, Lyon University Hospital, Lyon, France; Claude Bernard Lyon I University, Lyon, France; INSERM U1052, Lyon, France
| | - Damien Sanlaville
- CRNL, CNRS UMR 5292, INSERM U1028, Lyon, France; Department of Genetics, Lyon University Hospital, Lyon, France; Claude Bernard Lyon I University, Lyon, France
| | - Gaetan Lesca
- CRNL, CNRS UMR 5292, INSERM U1028, Lyon, France; Department of Genetics, Lyon University Hospital, Lyon, France; Claude Bernard Lyon I University, Lyon, France.
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17
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Campbell CL, Collins RT, Zarate YA. Severe neonatal presentation of Kleefstra syndrome in a patient with hypoplastic left heart syndrome and 9q34.3 microdeletion. ACTA ACUST UNITED AC 2014; 100:985-90. [DOI: 10.1002/bdra.23324] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- Candace L. Campbell
- University of Arkansas for Medical Sciences; Department of Pediatrics; Little Rock Arkansas
- University of Arkansas for Medical Sciences; Division of Cardiology; Little Rock Arkansas
| | - R. Thomas Collins
- University of Arkansas for Medical Sciences; Department of Pediatrics; Little Rock Arkansas
- University of Arkansas for Medical Sciences; Division of Cardiology; Little Rock Arkansas
- University of Arkansas for Medical Sciences; Department of Internal Medicine; Little Rock Arkansas
| | - Yuri A. Zarate
- University of Arkansas for Medical Sciences; Department of Pediatrics; Little Rock Arkansas
- University of Arkansas for Medical Sciences; Division of Genetics; Little Rock Arkansas
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18
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Davis BA, Isles AR. Modelling the genetic contribution to mental illness: a timely end for the psychiatric rodent? Eur J Neurosci 2014; 39:1933-42. [DOI: 10.1111/ejn.12607] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2013] [Revised: 03/11/2014] [Accepted: 04/01/2014] [Indexed: 01/09/2023]
Affiliation(s)
- Brittany A. Davis
- MRC Centre for Neuropsychiatric Genetics and Genomics; Neuroscience and Mental Health Research Institute; Cardiff University; Hadyn Ellis Building Maindy Road Cardiff CF24 4HQ UK
| | - Anthony R. Isles
- MRC Centre for Neuropsychiatric Genetics and Genomics; Neuroscience and Mental Health Research Institute; Cardiff University; Hadyn Ellis Building Maindy Road Cardiff CF24 4HQ UK
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19
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Mosaic 15q13.3 deletion including CHRNA7 gene in monozygotic twins. Eur J Med Genet 2013; 56:274-7. [DOI: 10.1016/j.ejmg.2013.02.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2012] [Accepted: 02/07/2013] [Indexed: 11/18/2022]
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20
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A mosaic maternal splice donor mutation in the EHMT1 gene leads to aberrant transcripts and to Kleefstra syndrome in the offspring. Eur J Hum Genet 2012; 21:887-90. [PMID: 23232695 DOI: 10.1038/ejhg.2012.267] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2012] [Revised: 10/26/2012] [Accepted: 11/01/2012] [Indexed: 02/04/2023] Open
Abstract
The euchromatic histone-lysine N-methyltransferase 1 (EHMT1) gene was examined in a 3-year-old boy with characteristic clinical features of Kleefstra syndrome. Sequencing of all 27 EHMT1 exons revealed a novel mutation, NM_024757.4:c.2712+1G>A, which affects the splice donor of intron 18. Whereas the index patient is heterozygous for that mutation, his phenotypically normal mother shows tissue-specific mosaicism. Sequencing of EHMT1 RT-PCR products revealed two aberrant transcript variants: in one variant, exon 18 was skipped; in the other, a near-by GT motif was used as splice donor and intronic sequence was inserted between exons 18 and 19. Both transcript variants were found in the patient and his mother. The latter had lower amounts of these transcripts consistent with mosaic status. This is the first description of an EHMT1 point mutation being inherited from a parent with verified mosaicism. The constitutive c.2712+1G>A splice site mutation in EHMT1 is fully pathogenic, and the transcript variants produced do not attenuate the severity of the disease.
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Willemsen MH, Vulto-van Silfhout AT, Nillesen WM, Wissink-Lindhout WM, van Bokhoven H, Philip N, Berry-Kravis EM, Kini U, van Ravenswaaij-Arts CMA, Delle Chiaie B, Innes AMM, Houge G, Kosonen T, Cremer K, Fannemel M, Stray-Pedersen A, Reardon W, Ignatius J, Lachlan K, Mircher C, Helderman van den Enden PTJM, Mastebroek M, Cohn-Hokke PE, Yntema HG, Drunat S, Kleefstra T. Update on Kleefstra Syndrome. Mol Syndromol 2012; 2:202-212. [PMID: 22670141 DOI: 10.1159/000335648] [Citation(s) in RCA: 85] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Kleefstra syndrome is characterized by the core phenotype of developmental delay/intellectual disability, (childhood) hypotonia and distinct facial features. The syndrome can be either caused by a microdeletion in chromosomal region 9q34.3 or by a mutation in the euchromatin histone methyltransferase 1 (EHMT1) gene. Since the early 1990s, 85 patients have been described, of which the majority had a 9q34.3 microdeletion (>85%). So far, no clear genotype-phenotype correlation could be observed by studying the clinical and molecular features of both 9q34.3 microdeletion patients and patients with an intragenic EHMT1 mutation. Thus, to further expand the genotypic and phenotypic knowledge about the syndrome, we here report 29 newly diagnosed patients, including 16 patients with a 9q34.3 microdeletion and 13 patients with an EHMT1 mutation, and review previous literature. The present findings are comparable to previous reports. In addition to our former findings and recommendations, we suggest cardiac screening during follow-up, because of the possible occurrence of cardiac arrhythmias. In addition, clinicians and caretakers should be aware of the regressive behavioral phenotype that might develop at adolescent/adult age and seems to have no clear neurological substrate, but is rather a so far unexplained neuropsychiatric feature.
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Affiliation(s)
- M H Willemsen
- Department of Human Genetics, Radboud University Nijmegen Medical Center, Nijmegen, The Netherlands
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