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Maalouf CA, Alberti A, Soutourina J. Mediator complex in transcription regulation and DNA repair: Relevance for human diseases. DNA Repair (Amst) 2024; 141:103714. [PMID: 38943827 DOI: 10.1016/j.dnarep.2024.103714] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2024] [Revised: 06/15/2024] [Accepted: 06/18/2024] [Indexed: 07/01/2024]
Abstract
The Mediator complex is an essential coregulator of RNA polymerase II transcription. More recent developments suggest Mediator functions as a link between transcription regulation, genome organisation and DNA repair mechanisms including nucleotide excision repair, base excision repair, and homologous recombination. Dysfunctions of these processes are frequently associated with human pathologies, and growing evidence shows Mediator involvement in cancers, neurological, metabolic and infectious diseases. The detailed deciphering of molecular mechanisms of Mediator functions, using interdisciplinary approaches in different biological models and considering all functions of this complex, will contribute to our understanding of relevant human diseases.
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Affiliation(s)
- Christelle A Maalouf
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette 91198, France
| | - Adriana Alberti
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette 91198, France
| | - Julie Soutourina
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette 91198, France.
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2
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de Souza GC, Malta MC, Santos MRS, Fontes MÍB, de Sousa Anjos JL, Ribeiro DP, Kok F, Figueiredo T. Novel ERLIN2 variant expands the phenotype of Spastic Paraplegia 18. Neurol Sci 2024; 45:2705-2710. [PMID: 38159148 DOI: 10.1007/s10072-023-07271-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Accepted: 12/16/2023] [Indexed: 01/03/2024]
Abstract
BACKGROUND The Brazilian Northeast region is notable for its high prevalence of consanguineous marriages and isolated populations, which has led to a significant prevalence of rare genetic disorders. This study describes the clinical presentation of four affected individuals from the same family, comprising two siblings and their cousins, with ages ranging from 11 to 20 years. METHODS In a small and isolated community in Northeastern Brazil, affected individuals initially underwent a clinical assessment. Subsequently, written consent was obtained from their legal guardians, and an extensive clinical evaluation was conducted at a medical genetics center. Family data provided the basis for constructing the pedigree, and biological samples (blood or oral swabs) were collected from both affected and unaffected family members. Following informed consent from one patient, Whole Exome Sequencing (WES) was carried out, encompassing exome sequencing, assembly, genotyping, and annotation. A potentially deleterious variant was then singled out for further segregation analysis through Sanger Sequencing, involving both the proband and select family members. RESULTS AND CONCLUSION These individuals exhibit severe neurodevelopmental delays, encompassing symptoms such as spastic paraplegia, neuropathy, intellectual impairments, and language challenges. Through next-generation sequencing (NGS) techniques, a previously unreported homozygous variant within the ERLIN2 gene linked to spastic paraplegia 18 (SPG18) was identified across all four patients. Also, all patients displayed childhood cataract, expanding the known clinical spectrum of SPG18.
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Affiliation(s)
| | - Maria Carolina Malta
- Medical Genetics Sector, Faculty of Medicine, Federal University of Alagoas, Maceió, Alagoas, Brazil
| | | | - Marshall Ítalo Barros Fontes
- Clinical Genetics Service, Medical Genetics Sector, Faculty of Medicine, University Hospital, Federal University of Alagoas, Maceió, Alagoas, Brazil
- Center of Health Sciences, Alagoas State University of Health Sciences-UNCISAL, Maceió, Alagoas, Brazil
| | - Juliana Lopes de Sousa Anjos
- Ophthalmology Sector, Faculty of Medicine, University Hospital, Federal University of Alagoas, Maceió, Alagoas, Brazil
| | - Diego Patrício Ribeiro
- Ophthalmology Sector, Faculty of Medicine, University Hospital, Federal University of Alagoas, Maceió, Alagoas, Brazil
| | - Fernando Kok
- Child Neurology Service, Department of Neurology, University of São Paulo School of Medicine, São Paulo, SP, Brazil
- Mendelics Genomic Analysis, São Paulo, SP, Brazil
| | - Thalita Figueiredo
- Medical Genetics Sector, Faculty of Medicine, Federal University of Alagoas, Maceió, Alagoas, Brazil.
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Gomes GRF, Mariano TC, Braga VLL, Ribeiro EM, Guimarães IP, Pereira KSAF, Nóbrega PR, Pessoa ALS. Bailey-Bloch Congenital Myopathy in Brazilian Patients: A Very Rare Myopathy with Malignant Hyperthermia Susceptibility. Brain Sci 2023; 13:1184. [PMID: 37626540 PMCID: PMC10452826 DOI: 10.3390/brainsci13081184] [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: 06/28/2023] [Revised: 07/21/2023] [Accepted: 07/25/2023] [Indexed: 08/27/2023] Open
Abstract
BACKGROUND Congenital myopathy-13 (CMYP13), also known as Bailey-Bloch congenital myopathy and Native American myopathy (NAM), is a condition caused by biallelic missense pathogenic variants in STAC3, which encodes an important protein necessary for the excitation-relaxation coupling machinery in the muscle. Patients with biallelic pathogenic variants in STAC3 often present with congenital weakness and arthrogryposis, cleft palate, ptosis, myopathic facies, short stature, kyphoscoliosis, and susceptibility to malignant hyperthermia provoked by anesthesia. We present two unrelated cases of Bailey-Bloch congenital myopathy descendants of non-consanguineous parents, which were investigated for delayed psychomotor development and generalized weakness. To the best of our knowledge, these are the first descriptions of CMYP13 in Brazil. In both patients, we found the previously described pathogenic missense variant p.Trp284Ser in homozygosity. CONCLUSION We seek to highlight the need for screening for CMYP13 in patients expressing the typical phenotype of the disease even in the absence of Lumbee Native American ancestry, and to raise awareness to possible complications like malignant hyperthermia in Bailey-Bloch congenital myopathy.
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Affiliation(s)
| | - Tamiris Carneiro Mariano
- Albert Sabin Pediatric Hospital (HIAS), Fortaleza 60410-794, Brazil; (T.C.M.); (V.L.L.B.); (E.M.R.)
| | - Vitor Lucas Lopes Braga
- Albert Sabin Pediatric Hospital (HIAS), Fortaleza 60410-794, Brazil; (T.C.M.); (V.L.L.B.); (E.M.R.)
| | - Erlane Marques Ribeiro
- Albert Sabin Pediatric Hospital (HIAS), Fortaleza 60410-794, Brazil; (T.C.M.); (V.L.L.B.); (E.M.R.)
- Faculty of Medicine, Unichristus University, Fortaleza 60160-196, Brazil;
| | - Ingred Pimentel Guimarães
- Faculty of Medicine, Ceará State University, Fortaleza 60714-903, Brazil; (G.R.F.G.); (I.P.G.); (K.S.A.F.P.)
| | | | - Paulo Ribeiro Nóbrega
- Faculty of Medicine, Unichristus University, Fortaleza 60160-196, Brazil;
- Division of Neurology, Department of Clinical Medicine, Federal University of Ceará, Fortaleza 60430-372, Brazil
| | - André Luiz Santos Pessoa
- Faculty of Medicine, Ceará State University, Fortaleza 60714-903, Brazil; (G.R.F.G.); (I.P.G.); (K.S.A.F.P.)
- Albert Sabin Pediatric Hospital (HIAS), Fortaleza 60410-794, Brazil; (T.C.M.); (V.L.L.B.); (E.M.R.)
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Pessoa ALS, Quesada AA, Nóbrega PR, Viana APO, de Oliveira KT, Figueiredo T, Santos S, Kok F. Neuropsychological Characterization of Autosomal Recessive Intellectual Developmental Disorder 59 Associated with IMPA1 (MRT59). Brain Sci 2023; 13:1048. [PMID: 37508980 PMCID: PMC10377093 DOI: 10.3390/brainsci13071048] [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: 06/21/2023] [Revised: 07/05/2023] [Accepted: 07/06/2023] [Indexed: 07/30/2023] Open
Abstract
Biallelic loss of function of IMPA1 causes autosomal recessive intellectual developmental disorder 59 (MRT59, OMIM #617323). MRT59 has been reported to present with significant intellectual disability and disruptive behavior, but little is known about the neurocognitive pattern of those patients. Thus, the aims of this study were: (1) to assess the cognitive profile of these patients, and (2) to evaluate their functional dependence levels. Eighteen adults, aged 37 to 89 years, participated in this study: nine MRT59 patients, five heterozygous carriers and four non-carrier family members. All of them were from a consanguineous family living in Northeast Brazil. All IMPA1 patients had the (c.489_493dupGGGCT) pathogenic variant in homozygosis. For cognitive assessment, the WASI battery was applied in nine MRT59 patients and compared to heterozygous carriers and non-carrier family members. Functional dependence was evaluated using the functional independence measure (FIM). Patients showed moderate to severe intellectual disability and severe functional disabilities. Heterozygous carriers did not differ from non-carriers. MRT59 patients should be followed up by health professionals in an interdisciplinary way to understand their cognitive disabilities and functional needs properly.
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Affiliation(s)
- Andre Luiz Santos Pessoa
- Albert Sabin Children's Hospital, Fortaleza 60410-794, Brazil
- Faculty of Medicine, State University of Ceará (UECE), Fortaleza 60714-903, Brazil
| | - Andrea Amaro Quesada
- The Edson Queiroz Foundation, University of Fortaleza (UNIFOR), Fortaleza 60811-905, Brazil
| | - Paulo Ribeiro Nóbrega
- Hospital Universitário Walter Cantídio-UFC, Fortaleza 60430-372, Brazil
- Faculty of Medicine, Centro Universitário Christus, Fortaleza 60160-230, Brazil
| | | | | | - Thalita Figueiredo
- Faculty of Medicine, Federal University of Alagoas (UFAL), Maceio 57200-000, Brazil
| | - Silvana Santos
- State University of Paraíba (UEPB), Campina Grande 58429-500, Brazil
| | - Fernando Kok
- Department of Neurology, University of São Paulo (USP), São Paulo 05508-220, Brazil
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Eigenhuis KN, Somsen HB, van den Berg DLC. Transcription Pause and Escape in Neurodevelopmental Disorders. Front Neurosci 2022; 16:846272. [PMID: 35615272 PMCID: PMC9125161 DOI: 10.3389/fnins.2022.846272] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Accepted: 04/11/2022] [Indexed: 11/17/2022] Open
Abstract
Transcription pause-release is an important, highly regulated step in the control of gene expression. Modulated by various factors, it enables signal integration and fine-tuning of transcriptional responses. Mutations in regulators of pause-release have been identified in a range of neurodevelopmental disorders that have several common features affecting multiple organ systems. This review summarizes current knowledge on this novel subclass of disorders, including an overview of clinical features, mechanistic details, and insight into the relevant neurodevelopmental processes.
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Wen J, Chai H, Grommisch B, DiAdamo A, Dykas D, Ma D, Popa A, Zhao C, Spencer-Manzon M, Jiang YH, McGrath J, Li P, Bale A, Zhang H. Detecting regions of homozygosity improves the diagnosis of pathogenic variants and uniparental disomy in pediatric patients. Am J Med Genet A 2022; 188:1728-1738. [PMID: 35199448 DOI: 10.1002/ajmg.a.62693] [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: 12/08/2021] [Revised: 01/12/2022] [Accepted: 01/28/2022] [Indexed: 11/10/2022]
Abstract
Chromosomal microarray analysis using single nucleotide polymorphism probes can detect regions of homozygosity (ROH). This confers a potential utility in revealing autosomal recessive (AR) diseases and uniparental disomy (UPD). Results of genetic testing among pediatric patients from 2015 to 2019 were evaluated. Diagnostic findings with detected ROH from large consecutive case series in the literature were reviewed. Of 2050 pediatric patients, 65 (3%) had one or more ROH and 31 (53%) had follow-up whole exome sequencing (WES) and methylation studies. Seven homozygous variants were detected and four of them from three patients (9.6%) were within the detected ROH and classified as pathogenic or likely pathogenic variants for AR diseases. One patient (3%) had segmental UPD15q for a diagnosis of Prader-Willi syndrome. Additive diagnostic yield from ROH reporting was at least 0.2% (4/2050) of pediatric patients. These results were consistent with findings from several large case series reported in the literature. Detecting ROH had an estimated baseline predictive value of 10% for AR diseases and 3% for UPD. Consanguinity revealed by multiple ROH was a strong predictor for AR diseases. These results provide evidence for genetic counseling and recommendation of follow-up WES and methylation studies for pediatric patients reported with ROH.
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Affiliation(s)
- Jiadi Wen
- Department of Genetics, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Hongyan Chai
- Department of Genetics, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Brittany Grommisch
- Department of Genetics, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Autumn DiAdamo
- Department of Genetics, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Daniel Dykas
- Department of Genetics, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Deqiong Ma
- Department of Genetics, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Andreea Popa
- Department of Genetics, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Chen Zhao
- Department of Genetics, Yale University School of Medicine, New Haven, Connecticut, USA
| | | | - Yong-Hui Jiang
- Department of Genetics, Yale University School of Medicine, New Haven, Connecticut, USA
| | - James McGrath
- Department of Comparative medicine, Yale University, New Haven, Connecticut, USA
| | - Peining Li
- Department of Genetics, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Allen Bale
- Department of Genetics, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Hui Zhang
- Department of Genetics, Yale University School of Medicine, New Haven, Connecticut, USA
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Carvalho LML, da Costa SS, Campagnari F, Kaufman A, Bertola DR, da Silva IT, Krepischi ACV, Koiffmann CP, Rosenberg C. Two novel pathogenic variants in MED13L: one familial and one isolated case. JOURNAL OF INTELLECTUAL DISABILITY RESEARCH : JIDR 2021; 65:1049-1057. [PMID: 34713510 DOI: 10.1111/jir.12891] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Revised: 08/12/2021] [Accepted: 09/19/2021] [Indexed: 06/13/2023]
Abstract
BACKGROUND Genetic variants involving the MED13L gene can lead to an autosomal dominant syndrome characterised by intellectual disability/developmental delay and facial dysmorphism. METHODS We investigated two cases (one familial and one isolated) of intellectual disability with speech delay and dysmorphic facial features by whole-exome sequencing analyses. Further, we performed a literature review about clinical and molecular aspects of MED13L gene and syndrome. RESULTS Two MED13L variants have been identified [MED13L(NM_015335.5):c.4417C>T and MED13L(NM_015335.5):c.2318delC] and were classified as pathogenic according to the ACMG (American College of Medical Genetics and Genomics) guidelines. One of the variants was present in sibs. CONCLUSIONS The two pathogenic variants identified have not been previously reported. Importantly, this is the first report of a familial case of MED13L nonsense mutation. Although the parents of the affected children were no longer available for analysis, their apparently normal phenotypes were surmised from familial verbal descriptions corresponding to normal mental behaviour and phenotype. In this situation, the familial component of mutation transmission might be caused by gonadal mosaicism of a MED13L mutation in a gonad from either the father or the mother. The case reports and the literature review presented in this manuscript can be useful for genetic counselling.
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Affiliation(s)
- L M L Carvalho
- Human Genome and Stem Cell Research Centre, Department of Genetics and Evolutionary Biology, Institute of Biosciences, University of São Paulo (USP), São Paulo, SP, Brazil
| | - S S da Costa
- Human Genome and Stem Cell Research Centre, Department of Genetics and Evolutionary Biology, Institute of Biosciences, University of São Paulo (USP), São Paulo, SP, Brazil
| | | | - A Kaufman
- Department of Psychiatry, Faculty of Medicine, University of São Paulo (USP), São Paulo, SP, Brazil
| | - D R Bertola
- Human Genome and Stem Cell Research Centre, Department of Genetics and Evolutionary Biology, Institute of Biosciences, University of São Paulo (USP), São Paulo, SP, Brazil
| | - I T da Silva
- International Centre for Research, A. C. Camargo Cancer Centre, São Paulo, SP, Brazil
| | - A C V Krepischi
- Human Genome and Stem Cell Research Centre, Department of Genetics and Evolutionary Biology, Institute of Biosciences, University of São Paulo (USP), São Paulo, SP, Brazil
| | - C P Koiffmann
- Human Genome and Stem Cell Research Centre, Department of Genetics and Evolutionary Biology, Institute of Biosciences, University of São Paulo (USP), São Paulo, SP, Brazil
| | - C Rosenberg
- Human Genome and Stem Cell Research Centre, Department of Genetics and Evolutionary Biology, Institute of Biosciences, University of São Paulo (USP), São Paulo, SP, Brazil
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Improving the phenotype description of Basel-Vanagaite-Smirin-Yosef syndrome, MED25-related: polymicrogyria as a distinctive neuroradiological finding. Neurogenetics 2020; 22:19-25. [PMID: 32816121 DOI: 10.1007/s10048-020-00625-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Accepted: 08/08/2020] [Indexed: 10/23/2022]
Abstract
Basel-Vanagaite-Smirin-Yosef syndrome (BVSYS) is an extremely rare autosomal recessive genetic disorder caused by variants in the MED25 gene. It is characterized by severe developmental delay and variable craniofacial, neurological, ocular, and cardiac anomalies. Since 2015, through whole exome sequencing, 20 patients have been described with common clinical features and biallelic variants in MED25, leading to a better definition of the phenotype associated with BVSYS. We report two young sisters, born to consanguineous parents, presenting with intellectual disability, neurological findings, and dysmorphic features typical of BVSYS, and also with bilateral perisylvian polymicrogyria. The younger sister died at the age of 1 year without autoptic examination. Whole exome sequencing detected a homozygous frameshift variant in the MED25 gene: NM_030973.3:c.1778_1779delAG, p.(Gln593Argfs). This report further delineates the most common clinical features of BVSYS and points to polymicrogyria as a distinctive neuroradiological feature of this syndrome.
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Haynes D, Pollack L, Prasad C, Goobie S, Colaiacovo S, Wolfinger T, Lacassie Y. Further delineation of Basel-Vanagaite-Smirin-Yosef syndrome: Report of three patients. Am J Med Genet A 2020; 182:1785-1790. [PMID: 32324310 DOI: 10.1002/ajmg.a.61603] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Revised: 02/28/2020] [Accepted: 04/01/2020] [Indexed: 01/17/2023]
Abstract
Basel-Vanagaite-Smirin-Yosef syndrome is a recently described autosomal recessive intellectual disability syndrome caused by variants in the MED25 gene. While it was originally identified in Brazil, it was further described in Israel by authors who are now the namesake of the condition. A 2018 publication further contributed to its delineation, but the patient's phenotype was complicated by a dual diagnosis. More recently, an article describing a set of affected siblings was published. We describe three, previously unreported, patients showing clinical variability for this newly defined syndrome. The major features determined by "reverse phenotyping" include significant to profound developmental delays/intellectual disability with absent or delayed speech, epilepsy, ocular abnormalities, cleft lip and/or palate, congenital heart disease, urogenital anomalies, skeletal abnormalities, brain malformations and/or microcephaly, failure to thrive, and dysmorphic features. The authors suggest the delineation of an acronym using the gene name and common features seen across the majority of patients reported so far. This new nomination, MED-DOCS, may help clinicians to recognize, suspect, and remember this novel syndrome.
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Affiliation(s)
- Devon Haynes
- Division of Genetics, Arnold Palmer Hospital for Children - Orlando Health, Orlando, Florida, USA
| | - Lynda Pollack
- Division of Genetics, Arnold Palmer Hospital for Children - Orlando Health, Orlando, Florida, USA
| | - Chitra Prasad
- Department of Pediatrics and Medical Genetics Program of Southwest Ontario, London Health Sciences Centre, London, Ontario, Canada
| | - Sharan Goobie
- Department of Paediatrics (Section of Genetics), Western University London, Ontario, Canada
| | - Samantha Colaiacovo
- Department of Pediatrics and Medical Genetics Program of Southwest Ontario, London Health Sciences Centre, London, Ontario, Canada
| | - Tara Wolfinger
- Division of Genetics, Arnold Palmer Hospital for Children - Orlando Health, Orlando, Florida, USA
| | - Yves Lacassie
- Division of Genetics, Department of Pediatrics, Louisiana State University Health Sciences Center and Children's Hospital, New Orleans, Louisiana, USA
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Nair P, Sabbagh S, Bizzari S, Brunner F, Stora S, Al-Ali MT, Gencik M, El-Hayek S, Mégarbané A. Report of a Second Lebanese Family with Basel-Vanagaite-Smirin-Yosef Syndrome: Possible Founder Mutation. Mol Syndromol 2019; 10:219-222. [PMID: 31602195 DOI: 10.1159/000501114] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/11/2019] [Indexed: 12/21/2022] Open
Abstract
Basel-Vanagaite-Smirin-Yosef syndrome (OMIM 616449) is a rare autosomal recessive genetic disorder characterized by severe developmental delay and variable craniofacial, neurological, cardiac, and ocular anomalies in the presence of variants in the MED25 gene. So far, only a handful of patients have been reported with this condition globally. Here, we report an additional Lebanese family with 2 affected siblings presenting with severely delayed psychomotor and language development as well as craniofacial anomalies. By whole-exome sequencing (WES), a homozygous variant was found in the MED25 gene, c.518T>C, predicted to result in a p.Ile173Thr change in the MED25 protein. This change has recently been reported in another Lebanese family. Review of the literature, the importance of this mutation in the Lebanese population, and the possibility that this condition may be underdiagnosed and only effectively detected using molecular techniques such as WES are discussed.
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Affiliation(s)
| | - Sandra Sabbagh
- Pediatrics Department, Hôtel-Dieu de France Hospital, Beirut, Lebanon
| | | | | | | | | | | | | | - André Mégarbané
- Institut Jérôme Lejeune, CRB BioJeL, Paris, France.,INOVIE-MENA, Beirut, Lebanon
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A population-based study of inter-generational attitudes towards consanguineous marriages in north-eastern Brazil. J Biosoc Sci 2019; 51:683-697. [PMID: 30862325 DOI: 10.1017/s0021932018000433] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The aim of this cross-sectional study was to investigate beliefs, attitudes and reproductive behaviours in relation to consanguinity in a population living in the backlands of north-eastern Brazil. Data were collected by face-to-face interview from 147 high school students aged 13-20 years and from 532 elderly individuals aged 60 years and over from Brejo dos Santos in the state of Paraíba in 2017. The frequency of consanguineous marriage was found to have increased over the generations, being 15.9% in the parents of the elderly participants, 17.1% in the elderly participants themselves and 20.5% in their descendants. Although 258 (50.9%) of the elderly interviewees opposed consanguineous union, 341 (65.3%) would approve of the marriage of their children with relatives. Both the young (n=108 or 78.3%) and elderly (n=398 or 80.4%) interviewees believed that consanguineous marriages were no more durable than non-consanguineous marriages (p=0.578). Additionally, 408 (82.4%) of the elderly individuals and 108 (80.6%) of the students recognized that spouses in consanguineous unions experience conflicts, just like other couples do (p=0.625). In both groups, the majority of the participants did not believe that consanguinity increased the risk of having children with disabilities. The regression of the two continuous variables 'age' and 'positive attitudes score' showed a significant correlation, suggesting that younger individuals are more susceptible to the influence of cultural factors contributing to consanguinity, such as the opinions of their parents and grandparents. The belief that consanguineous unions are more durable showed a significant difference between elderly individuals in consanguineous and non-consanguineous unions (p=0.001); the former were 2.42 more likely to believe that marriages between relatives contributes to marriage durability.
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Mir YR, Kuchay RAH. Advances in identification of genes involved in autosomal recessive intellectual disability: a brief review. J Med Genet 2019; 56:567-573. [PMID: 30842223 DOI: 10.1136/jmedgenet-2018-105821] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2018] [Revised: 02/01/2019] [Accepted: 02/11/2019] [Indexed: 12/28/2022]
Abstract
Intellectual disability (ID) is a clinically and genetically heterogeneous disorder, affecting 1%-3% of the general population. The number of ID-causing genes is high. Many X-linked genes have been implicated in ID. Autosomal dominant genes have recently been the focus of several large-scale studies. The total number of autosomal recessive ID (ARID) genes is estimated to be very high, and most are still unknown. Although research into the genetic causes of ID has recently gained momentum, identification of pathogenic mutations that cause ARID has lagged behind, predominantly due to non-availability of sizeable families. A commonly used approach to identify genetic loci for recessive disorders in consanguineous families is autozygosity mapping and whole-exome sequencing. Combination of these two approaches has recently led to identification of many genes involved in ID. These genes have diverse function and control various biological processes. In this review, we will present an update regarding genes that have been recently implicated in ID with focus on ARID.
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Affiliation(s)
- Yaser Rafiq Mir
- Department of Biotechnology, Baba Ghulam Shah Badshah University, Rajouri, Jammu and Kashmir, India
| | - Raja Amir Hassan Kuchay
- Department of Biotechnology, Baba Ghulam Shah Badshah University, Rajouri, Jammu and Kashmir, India
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Nair P, Lama M, El-Hayek S, Abou Sleymane G, Stora S, Obeid M, Al-Ali MT, Delague V, Mégarbané A. COQ8A and MED25 Mutations in a Child with Intellectual Disability, Microcephaly, Seizures, and Spastic Ataxia: Synergistic Effect of Digenic Variants? Mol Syndromol 2018; 9:319-323. [PMID: 30800049 DOI: 10.1159/000494465] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/29/2018] [Indexed: 12/31/2022] Open
Abstract
We report on a girl, born to first-cousin Lebanese parents, with severe intellectual disability, congenital hip luxation, cardiac malformation, short stature, facial dysmorphic features including microcephaly, sparse hair, bilateral epicanthal folds, ataxia, seizures, and elevated lactate and pyruvate levels in serum. Whole exome sequencing was carried out on the patient's DNA. Potentially causal homozygous variants in the MED25 (p.Ile173Thr) and COQ8A (p.Arg512Trp) genes were found. The potential pathogenicity of these variants, and the possibility that the 2 variants could synergistically act to produce the phenotype reported, is discussed.
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Affiliation(s)
- Pratibha Nair
- Centre for Arab Genomic Studies, Dubai, United Arab Emirates
| | - Maher Lama
- Pediatric Department El-Rassoul Hospital, Beirut, Lebanon
| | | | - Gretta Abou Sleymane
- Department of Laboratory Science and Technology, American University of Science and Technology, Beirut, Lebanon
| | | | - Marc Obeid
- Department of Laboratory Science and Technology, American University of Science and Technology, Beirut, Lebanon
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Origin and age of the causative mutations in KLC2, IMPA1, MED25 and WNT7A unravelled through Brazilian admixed populations. Sci Rep 2018; 8:16552. [PMID: 30410084 PMCID: PMC6224410 DOI: 10.1038/s41598-018-35022-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Accepted: 10/23/2018] [Indexed: 12/13/2022] Open
Abstract
The mutation age and local ancestry of chromosomal segments harbouring mutations associated with autosomal recessive (AR) disorders in Brazilian admixed populations remain unknown; additionally, inbreeding levels for these affected individuals continue to be estimated based on genealogical information. Here, we calculated inbreeding levels using a runs of homozygosity approach, mutation age and local ancestry to infer the origin of each chromosomal segments containing disorder-causing mutations in KLC2, IMPA1, MED25 and WNT7A. Genotyped data were generated from 18 patients affected by AR diseases and combined to the 1000 genome project (1KGP) and Simons genome diversity project (SGDP) databases to infer local ancestry. We found a major European contribution for mutated haplotypes with recent mutation age and inbreeding values found only in Native American and Middle East individuals. These results contribute to identifying the origin of and to understanding how these diseases are maintained and spread in Brazilian and world populations.
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15
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Sierecki E. The Mediator complex and the role of protein-protein interactions in the gene regulation machinery. Semin Cell Dev Biol 2018; 99:20-30. [PMID: 30278226 DOI: 10.1016/j.semcdb.2018.08.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Revised: 08/13/2018] [Accepted: 08/13/2018] [Indexed: 12/11/2022]
Abstract
At the core of gene regulation, a complex network of dynamic interactions between proteins, DNA and RNA has to be integrated in order to generate a binary biological output. Large protein complexes, called adaptors, transfer information from the transcription factors to the transcription machinery [1,2]. Here we focus on Mediator, one of the largest adaptor proteins in humans [3]. Assembled from 30 different subunits, this system provides extraordinary illustrations for the various roles played by protein-protein interactions. Recruitment of new subunits during evolution is an adaptive mechanism to the growing complexity of the organism. Integration of information happens at multiple scales, with allosteric effects at the level of individual subunits resulting in large conformational changes. Mediator is also rich in disordered regions that increase the potential for interactions by presenting a malleable surface to its environment. Potentially, 3000 transcription factors can interact with Mediator and so understanding the molecular mechanisms that support the processing of this overload of information is one of the great challenges in molecular biology.
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Affiliation(s)
- Emma Sierecki
- EMBL Australia Node in Single Molecule Science, and School of Medical Sciences, Faculty of Medecine, The University of New South Wales, Sydney, Australia.
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16
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Asadollahi R, Zweier M, Gogoll L, Schiffmann R, Sticht H, Steindl K, Rauch A. Genotype-phenotype evaluation of MED13L defects in the light of a novel truncating and a recurrent missense mutation. Eur J Med Genet 2017. [PMID: 28645799 DOI: 10.1016/j.ejmg.2017.06.004] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
A decade after the designation of MED13L as a gene and its link to intellectual disability (ID) and dextro-looped transposition of great arteries in 2003, we previously described a recognizable syndrome due to MED13L haploinsufficiency. Subsequent reports of 22 further patients diagnosed by genome-wide testing further delineated the syndrome with expansion of the phenotypic spectrum and showed reduced penetrance for congenital heart defects. We now report two novel patients identified by whole exome sequencing, one with a de novo MED13L truncating mutation and the other with a de novo missense mutation. The first patient indicates some facial resemblance to Kleefstra syndrome as a novel differential diagnosis, and the second patient shows, for the first time, recurrence of a MED13L missense mutation (p.(Asp860Gly)). Notably, our in silico modelling predicted this missense mutation to decrease the stability of an alpha-helix and thereby affecting the MED13L secondary structure, while the majority of published missense mutations remain variants of uncertain significance. Review of the reported patients with MED13L haploinsufficiency indicates moderate to severe ID and facial anomalies in all patients, as well as severe speech delay and muscular hypotonia in the majority. Further common signs include abnormal MRI findings of myelination defects and abnormal corpus callosum, ataxia and coordination problems, autistic features, seizures/abnormal EEG, or congenital heart defects, present in about 20-50% of the patients. With reference to facial anomalies, the majority of patients were reported to show broad/prominent forehead, low set ears, bitemporal narrowing, upslanting palpebral fissures, depressed/flat nasal bridge, bulbous nose, and abnormal chin, but macroglossia and horizontal eyebrows were also observed in ∼30%. The latter are especially important in the differential diagnosis of 1p36 deletion and Kleefstra syndromes, while the more common facial gestalt shows some resemblance to 22q11.2 deletion syndrome. Despite the fact that MED13L was found to be one of the most common ID genes in the Deciphering Developmental Disorders Study, further detailed patient descriptions are needed to explore the full clinical spectrum, potential genotype-phenotype correlations, as well as the role of missense mutations and potential mutational hotspots along the gene.
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Affiliation(s)
- Reza Asadollahi
- Institute of Medical Genetics, University of Zurich, Schlieren-Zurich, Switzerland
| | - Markus Zweier
- Institute of Medical Genetics, University of Zurich, Schlieren-Zurich, Switzerland
| | - Laura Gogoll
- Institute of Medical Genetics, University of Zurich, Schlieren-Zurich, Switzerland
| | - Raphael Schiffmann
- Institute of Metabolic Disease, Baylor Scott & White Research Institute, Dallas, TX, USA
| | - Heinrich Sticht
- Institute of Biochemistry, University of Erlangen-Nuremberg, Erlangen, Germany
| | - Katharina Steindl
- Institute of Medical Genetics, University of Zurich, Schlieren-Zurich, Switzerland
| | - Anita Rauch
- Institute of Medical Genetics, University of Zurich, Schlieren-Zurich, Switzerland; Neuroscience Center Zurich, University of Zurich, Zurich, Switzerland; Zurich Center of Integrative Human Physiology, University of Zurich, Zurich, Switzerland.
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17
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Izumi K. Disorders of Transcriptional Regulation: An Emerging Category of Multiple Malformation Syndromes. Mol Syndromol 2016; 7:262-273. [PMID: 27867341 DOI: 10.1159/000448747] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/13/2016] [Indexed: 01/09/2023] Open
Abstract
Some genetic disorders caused by mutations in genes encoding components of the transcriptional machinery as well as proteins involved in epigenetic modification of the genome share many overlapping features, such as facial dysmorphisms, growth problems and developmental delay/intellectual disability. As a basis for some shared phenotypic characteristics in these syndromes, a similar transcriptome disturbance, characterized by global transcriptional dysregulation, is believed to play a major role. In this review article, a general overview of gene transcription is provided, and the current knowledge of the mechanisms underlying some disorders of transcriptional regulation, such as Rubinstein- Taybi, Coffin-Siris, Cornelia de Lange, and CHOPS syndromes, are discussed.
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Affiliation(s)
- Kosuke Izumi
- Division of Human Genetics, The Children's Hospital of Philadelphia, Philadelphia, Pa., USA
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18
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Figueiredo T, Melo US, Pessoa ALS, Nobrega PR, Kitajima JP, Rusch H, Vaz F, Lucato LT, Zatz M, Kok F, Santos S. A homozygous loss-of-function mutation in inositol monophosphatase 1 (IMPA1) causes severe intellectual disability. Mol Psychiatry 2016; 21:1125-9. [PMID: 26416544 DOI: 10.1038/mp.2015.150] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2015] [Revised: 08/17/2015] [Accepted: 08/19/2015] [Indexed: 11/09/2022]
Abstract
The genetic basis of intellectual disability (ID) is extremely heterogeneous and relatively little is known about the role of autosomal recessive traits. In a field study performed in a highly inbred area of Northeastern Brazil, we identified and investigated a large consanguineous family with nine adult members affected by severe ID associated with disruptive behavior. The Genome-Wide Human SNP Array 6.0 microarray was used to determine regions of homozygosity by descent from three affected and one normal family member. Whole-exome sequencing (WES) was performed in one affected patient using the Nextera Rapid-Capture Exome kit and Illumina HiSeq2500 system to identify the causative mutation. Potentially deleterious variants detected in regions of homozygosity by descent and not present in either 59 723 unrelated individuals from the Exome Aggregation Consortium (Browser) or 1484 Brazilians were subject to further scrutiny and segregation analysis by Sanger sequencing. Homozygosity-by-descent analysis disclosed a 20.7-Mb candidate region at 8q12.3-q21.2 (lod score: 3.11). WES identified a homozygous deleterious variant in inositol monophosphatase 1 (IMPA1) (NM_005536), consisting of a 5-bp duplication (c.489_493dupGGGCT; chr8: 82,583,247; GRCh37/hg19) leading to a frameshift and a premature stop codon (p.Ser165Trpfs*10) that cosegregated with the disease in 26 genotyped family members. The IMPA1 gene product is responsible for the final step of biotransformation of inositol triphosphate and diacylglycerol, two second messengers. Despite its many physiological functions, no clinical phenotype has been assigned to this gene dysfunction to date. Additionally, IMPA1 is the main target of lithium, a drug that is at the forefront of treatment for bipolar disorder.
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Affiliation(s)
- T Figueiredo
- Northeast Biotechnology Network (RENORBIO), Federal University of Paraiba (UFPB), Joao Pessoa, Brazil.,Department of Biology, Paraiba State University (UEPB), Campina Grande, Brazil.,Department of Genetics and Evolutionary Biology, Human Genome and Stem Cell Research Center, Biosciences Institute, University of Sao Paulo (USP), Sao Paulo, Brazil
| | - U S Melo
- Department of Genetics and Evolutionary Biology, Human Genome and Stem Cell Research Center, Biosciences Institute, University of Sao Paulo (USP), Sao Paulo, Brazil
| | - A L S Pessoa
- Department of Neurology, School of Medicine, University of Sao Paulo (USP), Sao Paulo, Brazil.,School of Medicine, Fortaleza University (UNIFOR), Fortaleza, Brazil
| | - P R Nobrega
- Department of Neurology, School of Medicine, University of Sao Paulo (USP), Sao Paulo, Brazil
| | | | - H Rusch
- Laboratory of Genetic Metabolic Diseases, Department of Clinical Chemistry, University of Amsterdam, Academic Medical Center (AMC), Amsterdam, The Netherlands
| | - F Vaz
- Laboratory of Genetic Metabolic Diseases, Department of Clinical Chemistry, University of Amsterdam, Academic Medical Center (AMC), Amsterdam, The Netherlands
| | - L T Lucato
- Institute of Radiology, School of Medicine, University of Sao Paulo (USP), Sao Paulo, Brazil
| | - M Zatz
- Department of Genetics and Evolutionary Biology, Human Genome and Stem Cell Research Center, Biosciences Institute, University of Sao Paulo (USP), Sao Paulo, Brazil
| | - F Kok
- Department of Genetics and Evolutionary Biology, Human Genome and Stem Cell Research Center, Biosciences Institute, University of Sao Paulo (USP), Sao Paulo, Brazil.,Department of Neurology, School of Medicine, University of Sao Paulo (USP), Sao Paulo, Brazil.,Mendelics Genomic Analysis, Sao Paulo, Brazil
| | - S Santos
- Northeast Biotechnology Network (RENORBIO), Federal University of Paraiba (UFPB), Joao Pessoa, Brazil.,Department of Biology, Paraiba State University (UEPB), Campina Grande, Brazil
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One family, one gene and three phenotypes: A novel VCP (valosin-containing protein) mutation associated with myopathy with rimmed vacuoles, amyotrophic lateral sclerosis and frontotemporal dementia. J Neurol Sci 2016; 368:352-8. [PMID: 27538664 DOI: 10.1016/j.jns.2016.07.048] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Revised: 07/16/2016] [Accepted: 07/20/2016] [Indexed: 12/12/2022]
Abstract
BACKGROUND VCP (valosin-containing protein gene) variants have been associated with peripheral and central neurodegenerative processes, including inclusion body myopathy (IBM), Paget disease of bone (PDB), frontotemporal dementia (FTD), and familial amyotrophic lateral sclerosis (ALS) type 14. The combination of IBM, PDB (IBMPFD1) can presented in one individual. However, the association of IBMPFD1 and ALS in the same family is rare. METHODS We reported three individuals from a Brazilian kindred with intrafamilial phenotype variability. Whole exome sequencing (WES) of the proband was performed and revealed a novel VCP variant. VCP Sanger sequencing was performed in the proband and his family members to confirm WES finding and segregation. We performed a systematic review of the literature regarding the genotypic-phenotypic VCP correlations. RESULTS Each individual presented with either myopathy with rimmed vacuoles, ALS, or FTD. There was no PDB. WES of the proband identified the heterozygous variant c.271A>T (p.Asn91Tyr) in the exon 3 of VCP. Sanger sequencing confirmed the segregation of this variant in an autosomal-dominant pattern. CONCLUSION This study expands the genotypic spectrum of the missense mutations of the VCP gene with a novel p.Asn91Tyr variant found in a Brazilian family presenting with the unusual intrafamiliar association of myopathy with rimmed vacuoles, ALS and FTD.
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20
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Zatz M, Passos-Bueno MR, Vainzof M. Neuromuscular disorders: genes, genetic counseling and therapeutic trials. Genet Mol Biol 2016; 39:339-48. [PMID: 27575431 PMCID: PMC5004840 DOI: 10.1590/1678-4685-gmb-2016-0019] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Accepted: 03/29/2016] [Indexed: 02/07/2023] Open
Abstract
Neuromuscular disorders (NMD) are a heterogeneous group of genetic conditions, with autosomal dominant, recessive, or X-linked inheritance. They are characterized by progressive muscle degeneration and weakness. Here, we are presenting our major contributions to the field during the past 30 years. We have mapped and identified several novel genes responsible for NMD. Genotype-phenotype correlations studies enhanced our comprehension on the effect of gene mutations on related proteins and their impact on clinical findings. The search for modifier factors allowed the identification of a novel "protective"; variant which may have important implication on therapeutic developments. Molecular diagnosis was introduced in the 1980s and new technologies have been incorporated since then. Next generation sequencing greatly improved our capacity to identify disease-causing mutations with important benefits for research and prevention through genetic counseling of patients' families. Stem cells researches, from and for patients, have been used as tools to study human genetic diseases mechanisms and for therapies development. The clinical effect of preclinical trials in mice and canine models for muscular dystrophies are under investigation. Finally, the integration of our researches and genetic services with our post-graduation program resulted in a significant output of new geneticists, spreading out this expertise to our large country.
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Affiliation(s)
- Mayana Zatz
- Human Genome and Research Center (HUG-CELL), Instituto de
Biociências, Universidade de São Paulo (USP), São Paulo, SP, Brazil
| | - Maria Rita Passos-Bueno
- Human Genome and Research Center (HUG-CELL), Instituto de
Biociências, Universidade de São Paulo (USP), São Paulo, SP, Brazil
| | - Mariz Vainzof
- Human Genome and Research Center (HUG-CELL), Instituto de
Biociências, Universidade de São Paulo (USP), São Paulo, SP, Brazil
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21
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Homozygous MED25 mutation implicated in eye-intellectual disability syndrome. Hum Genet 2015; 134:577-87. [PMID: 25792360 DOI: 10.1007/s00439-015-1541-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2014] [Accepted: 03/11/2015] [Indexed: 12/26/2022]
Abstract
Genetic syndromes involving both brain and eye abnormalities are numerous and include syndromes such as Warburg micro syndrome, Kaufman oculocerebrofacial syndrome, Cerebro-oculo-facio-skeletal syndrome, Kahrizi syndrome and others. Using exome sequencing, we have been able to identify homozygous mutation p.(Tyr39Cys) in MED25 as the cause of a syndrome characterized by eye, brain, cardiac and palatal abnormalities as well as growth retardation, microcephaly and severe intellectual disability in seven patients from four unrelated families, all originating from the same village. The protein encoded by MED25 belongs to Mediator complex or MED complex, which is an evolutionary conserved multi-subunit RNA polymerase II transcriptional regulator complex. The MED25 point mutation is located in the von Willebrand factor type A (MED25 VWA) domain which is responsible for MED25 recruitment into the Mediator complex; co-immunoprecipitation experiment demonstrated that this mutation dramatically impairs MED25 interaction with the Mediator complex in mammalian cells.
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