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Yang F, Wang M. Effect of the OPHN1 novel variant c.1025+1 G>A on RNA splicing: insights from a minigene assay. BMC Med Genomics 2024; 17:175. [PMID: 38956616 PMCID: PMC11221095 DOI: 10.1186/s12920-024-01952-1] [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: 12/26/2023] [Accepted: 06/27/2024] [Indexed: 07/04/2024] Open
Abstract
This research analyzes the clinical data, whole-exome sequencing results, and in vitro minigene functional experiments of a child with developmental delay and intellectual disability. The male patient, aged 4, began experiencing epileptic seizures at 3 months post-birth and has shown developmental delay. Rehabilitation training was administered between the ages of one and two. There were no other significant family medical histories. Through comprehensive family exome genetic testing, a hemizygous variant in the 11th exon of the OPHN1 gene was identified in the affected child: c.1025 + 1G > A. Family segregation analysis confirmed the presence of this variant in the patient's mother, which had not been previously reported. According to the ACMG guidelines, this variant was classified as a likely pathogenic variant. In response to this variant, an in vitro minigene functional experiment was designed and conducted, confirming that the mutation affects the normal splicing of the gene's mRNA, resulting in a 56 bp retention on the left side of Intron 11. It was confirmed that OPHN1: c.1025 + 1G > A is the pathogenic cause of X-linked intellectual disabilities in the child, with clinical phenotypes including developmental delay and seizures.
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Affiliation(s)
- Fei Yang
- Changde Hospital, Xiangya School of Medicine, Central South University(The First People's Hospital of Changde City), No.818 Renmin Road, Changde, Hunan, 415000, China
| | - Minghui Wang
- Changde Hospital, Xiangya School of Medicine, Central South University(The First People's Hospital of Changde City), No.818 Renmin Road, Changde, Hunan, 415000, China.
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2
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Lubala TK, Kayembe-Kitenge T, Mubungu G, Lumaka A, Kanteng G, Savage S, Luboya O, Hagerman R, Devriendt K, Lukusa-Tshilobo P. Usefulness of automated image analysis for recognition of the fragile X syndrome gestalt in Congolese subjects. Eur J Med Genet 2023; 66:104819. [PMID: 37532084 DOI: 10.1016/j.ejmg.2023.104819] [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: 12/07/2022] [Revised: 07/16/2023] [Accepted: 07/30/2023] [Indexed: 08/04/2023]
Abstract
BACKGROUND Computer-aided software such as the facial image diagnostic aid (FIDA) and Face2Gene has been developed to perform pattern recognition of facial features with promising clinical results. The aim of this pilot study was to test Face2Gene's recognition performance on Bantu Congolese subjects with Fragile X syndrome (FXS) as compared to Congolese subjects with intellectual disability but without FXS (non-FXS). METHOD Frontal facial photograph from 156 participants (14 patients with FXS and 142 controls) predominantly young-adults to adults, median age 18.9 age range 4-39yo, were uploaded. Automated face analysis was conducted by using the technology used in proprietary software tools called Face2Gene CLINIC and Face2Gene RESEARCH (version 17.6.2). To estimate the statistical power of the Face2Gene technology in distinguishing affected individuals from controls, a cross validation scheme was used. RESULTS The similarity seen in the upper facial region (of males and females) is greater than the similarity seen in other parts of the face. Binary comparison of subjects with FXS versus non-FXS and subjects with FXS versus subjects with Down syndrome reveal an area under the curve values of 0.955 (p = 0.002) and 0.986 (p = 0.003). CONCLUSION The Face2Gene algorithm is separating well between FXS and Non-FXS subjects.
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Affiliation(s)
- Toni Kasole Lubala
- Division of Dysmorphology & Birth Defects, Department of Pediatrics, University of Lubumbashi, Democratic Republic of the Congo
| | - Tony Kayembe-Kitenge
- Unit of Toxicology and Environment, School of Public Health, University of Lubumbashi, Democratic Republic of the Congo; Center for Environment and Health, Department of Public Health and Primary Care, KU Leuven, Leuven, Belgium; Higher Institute of Medical Techniques, Lubumbashi, Democratic Republic of the Congo.
| | - Gerrye Mubungu
- Department of Pediatrics, Faculty of Medicine, University of Kinshasa, Democratic Republic of the Congo; Center for Human Genetics, National Institute for Biomedical Research (NIBR), Democratic Republic of the Congo; Center for Human Genetics, University Hospital Leuven, University of Leuven, Belgium
| | - Aimé Lumaka
- Department of Pediatrics, Faculty of Medicine, University of Kinshasa, Democratic Republic of the Congo; Center for Human Genetics, National Institute for Biomedical Research (NIBR), Democratic Republic of the Congo; Center for Human Genetics, University Hospital Leuven, University of Leuven, Belgium; Department of Biomedical and Preclinical Sciences, GIGA-Rm Laboratory of Human Genetics, University of Liège, Liège, Belgium
| | - Gray Kanteng
- Division of Dysmorphology & Birth Defects, Department of Pediatrics, University of Lubumbashi, Democratic Republic of the Congo
| | | | - Oscar Luboya
- Division of Dysmorphology & Birth Defects, Department of Pediatrics, University of Lubumbashi, Democratic Republic of the Congo; Higher Institute of Medical Techniques, Lubumbashi, Democratic Republic of the Congo
| | - Randi Hagerman
- Department of Pediatrics, MIND Institute, University of California Davis Medical Center, Sacramento, CA, USA
| | - Koenraad Devriendt
- Center for Human Genetics, University Hospital Leuven, University of Leuven, Belgium
| | - Prosper Lukusa-Tshilobo
- Department of Pediatrics, Faculty of Medicine, University of Kinshasa, Democratic Republic of the Congo; Center for Human Genetics, National Institute for Biomedical Research (NIBR), Democratic Republic of the Congo; Center for Human Genetics, University Hospital Leuven, University of Leuven, Belgium
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3
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Functions of CNKSR2 and Its Association with Neurodevelopmental Disorders. Cells 2022; 11:cells11020303. [PMID: 35053419 PMCID: PMC8774548 DOI: 10.3390/cells11020303] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2021] [Revised: 01/05/2022] [Accepted: 01/13/2022] [Indexed: 02/04/2023] Open
Abstract
The Connector Enhancer of Kinase Suppressor of Ras-2 (CNKSR2), also known as CNK2 or MAGUIN, is a scaffolding molecule that contains functional protein binding domains: Sterile Alpha Motif (SAM) domain, Conserved Region in CNK (CRIC) domain, PSD-95/Dlg-A/ZO-1 (PDZ) domain, Pleckstrin Homology (PH) domain, and C-terminal PDZ binding motif. CNKSR2 interacts with different molecules, including RAF1, ARHGAP39, and CYTH2, and regulates the Mitogen-Activated Protein Kinase (MAPK) cascade and small GTPase signaling. CNKSR2 has been reported to control the development of dendrite and dendritic spines in primary neurons. CNKSR2 is encoded by the CNKSR2 gene located in the X chromosome. CNKSR2 is now considered as a causative gene of the Houge type of X-linked syndromic mental retardation (MRXHG), an X-linked Intellectual Disability (XLID) that exhibits delayed development, intellectual disability, early-onset seizures, language delay, attention deficit, and hyperactivity. In this review, we summarized molecular features, neuronal function, and neurodevelopmental disorder-related variations of CNKSR2.
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Benmakhlouf Y, Touraine R, Harzallah I, Zian Z, Ben Makhlouf K, Barakat A, Ghailani Nourouti N, Bennani Mechita M. Screening of the duplication 24 pb of ARX gene in Moroccan patients with X-linked Intellectual Disability. BMC Res Notes 2021; 14:110. [PMID: 33757564 PMCID: PMC7988900 DOI: 10.1186/s13104-021-05526-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Accepted: 03/13/2021] [Indexed: 11/10/2022] Open
Abstract
OBJECTIVE Intellectual Disability (ID) represents a neuropsychiatric disorder, which its etiopathogenesis remains insufficiently understood. Mutations in the Aristaless Related Homeobox gene (ARX) have been identified to cause syndromic and nonsyndromic (NS-ID). The most recurrent mutation of this gene is a duplication of 24pb, c.428-451dup. Epidemiological and genetic studies about ID in the Moroccan population remain very scarce, and none study is carried out on the ARX gene. This work aimed to study c.428-451dup (24 bp) mutation in the exon 2 of the ARX gene in 118 males' Moroccan patients with milder NS-ID to evaluate if the gene screening is a good tool for identifying NS-ID. RESULTS Our mutational analysis did not show any dup(24pb) in our patients. This is because based on findings from previous studies that found ARX mutations in 70% of families with NS-ID, and in most cases, 1.5-6.1% of individuals with NS-ID have this duplication. Since 1/118 = 0.0084 (0.84%) is not much different from 1.5%, then it is reasonable that this could a sample size artifact. A complete screening of the entire ARX gene, including the five exons, should be fulfilled. Further investigations are required to confirm these results.
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Affiliation(s)
- Yousra Benmakhlouf
- Biomedical Genomics and Oncogenetics Research Laboratory, Faculty of Sciences and Techniques of Tangier, University Abdelmalek Essaadi, P.B.:416, Tangier, Morocco.
| | | | - Ines Harzallah
- Molecular Genetics Laboratory, CHU, Saint Etienne, France
| | - Zeineb Zian
- Biomedical Genomics and Oncogenetics Research Laboratory, Faculty of Sciences and Techniques of Tangier, University Abdelmalek Essaadi, P.B.:416, Tangier, Morocco
| | | | - Amina Barakat
- Biomedical Genomics and Oncogenetics Research Laboratory, Faculty of Sciences and Techniques of Tangier, University Abdelmalek Essaadi, P.B.:416, Tangier, Morocco
| | - Naima Ghailani Nourouti
- Biomedical Genomics and Oncogenetics Research Laboratory, Faculty of Sciences and Techniques of Tangier, University Abdelmalek Essaadi, P.B.:416, Tangier, Morocco
| | - Mohcine Bennani Mechita
- Biomedical Genomics and Oncogenetics Research Laboratory, Faculty of Sciences and Techniques of Tangier, University Abdelmalek Essaadi, P.B.:416, Tangier, Morocco
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Bogliş A, Cosma AS, Tripon F, Bãnescu C. Exon 21 deletion in the OPHN1 gene in a family with syndromic X-linked intellectual disability: Case report. Medicine (Baltimore) 2020; 99:e21632. [PMID: 32872024 PMCID: PMC7437857 DOI: 10.1097/md.0000000000021632] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
INTRODUCTION The oligophrenin-1 (OPHN1) gene, localized on the X chromosome, is a Rho-GTPase activating protein that is related to syndromic X-linked intellectual disability (XLID). XLID, characterized by brain anomalies, namely cerebellar hypoplasia, specific facial features, and intellectual disability, is produced by different mutations in the OPHN1 gene. PATIENT CONCERNS In this report, we present the clinical and molecular findings of a family affected by a mild XLID due to a deletion in the OPHN1 gene, exon 21, Xq12 region using Multiplex Ligation-dependent Probe Amplification (MLPA) analysis. The clinical features present in the family are a mild developmental delay, behavioral disturbances, facial dysmorphism, pes planus, nystagmus, strabismus, epilepsy, and occipital arachnoid cyst. INTERVENTIONS The MLPA analysis was performed for investigation of the copy number variations within the X chromosome for the family. DIAGNOSIS AND OUTCOME The MLPA analysis detected a deletion in the OPHN1 gene, exon 21 for the proband, and a heterozygous deletion for the probands mother. The deletion of the Xq12 region of maternal origin, including the exon 21 of the OPHN1 gene, confirmed for the probands nephew. LESSONS Our findings emphasize the utility of the MLPA analysis to identify deletions in the OPHN1 gene responsible for syndromic XLID. Therefore, we suggest that MLPA analysis should be performed as an alternative diagnostic test for all patients with a mild intellectual disability associated or not with behavioral disturbances, facial dysmorphism, and brain anomalies.
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Affiliation(s)
- Alina Bogliş
- Laboratory of Medical Genetics, Emergency Clinical County Hospital Târgu Mureş, Târgu Mureş¸ Romania
- Department of Genetics, George Emil Palade University of Medicine, Pharmacy, Sciences, and Technology of Târgu Mureş, Târgu Mureş, Romania
- Laboratory of Molecular Biology/Genetics, Center for Advanced Medical and Pharmaceutical Research, George Emil Palade University of Medicine, Pharmacy, Sciences, and Technology of Târgu Mureş, Târgu Mureş, Romania
| | - Adriana S. Cosma
- Laboratory of Medical Genetics, Emergency Clinical County Hospital Târgu Mureş, Târgu Mureş¸ Romania
| | - Florin Tripon
- Laboratory of Medical Genetics, Emergency Clinical County Hospital Târgu Mureş, Târgu Mureş¸ Romania
- Department of Genetics, George Emil Palade University of Medicine, Pharmacy, Sciences, and Technology of Târgu Mureş, Târgu Mureş, Romania
- Laboratory of Molecular Biology/Genetics, Center for Advanced Medical and Pharmaceutical Research, George Emil Palade University of Medicine, Pharmacy, Sciences, and Technology of Târgu Mureş, Târgu Mureş, Romania
| | - Claudia Bãnescu
- Laboratory of Medical Genetics, Emergency Clinical County Hospital Târgu Mureş, Târgu Mureş¸ Romania
- Department of Genetics, George Emil Palade University of Medicine, Pharmacy, Sciences, and Technology of Târgu Mureş, Târgu Mureş, Romania
- Laboratory of Molecular Biology/Genetics, Center for Advanced Medical and Pharmaceutical Research, George Emil Palade University of Medicine, Pharmacy, Sciences, and Technology of Târgu Mureş, Târgu Mureş, Romania
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Al-Naama N, Mackeh R, Kino T. C 2H 2-Type Zinc Finger Proteins in Brain Development, Neurodevelopmental, and Other Neuropsychiatric Disorders: Systematic Literature-Based Analysis. Front Neurol 2020; 11:32. [PMID: 32117005 PMCID: PMC7034409 DOI: 10.3389/fneur.2020.00032] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Accepted: 01/10/2020] [Indexed: 12/15/2022] Open
Abstract
Neurodevelopmental disorders (NDDs) are multifaceted pathologic conditions manifested with intellectual disability, autistic features, psychiatric problems, motor dysfunction, and/or genetic/chromosomal abnormalities. They are associated with skewed neurogenesis and brain development, in part through dysfunction of the neural stem cells (NSCs) where abnormal transcriptional regulation on key genes play significant roles. Recent accumulated evidence highlights C2H2-type zinc finger proteins (C2H2-ZNFs), the largest transcription factor family in humans, as important targets for the pathologic processes associated with NDDs. In this review, we identified their significant accumulation (74 C2H2-ZNFs: ~10% of all human member proteins) in brain physiology and pathology. Specifically, we discuss their physiologic contribution to brain development, particularly focusing on their actions in NSCs. We then explain their pathologic implications in various forms of NDDs, such as morphological brain abnormalities, intellectual disabilities, and psychiatric disorders. We found an important tendency that poly-ZNFs and KRAB-ZNFs tend to be involved in the diseases that compromise gross brain structure and human-specific higher-order functions, respectively. This may be consistent with their characteristic appearance in the course of species evolution and corresponding contribution to these brain activities.
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Affiliation(s)
- Njoud Al-Naama
- Laboratory of Molecular and Genomic Endocrinology, Division of Translational Medicine, Sidra Medicine, Doha, Qatar
| | - Rafah Mackeh
- Laboratory of Molecular and Genomic Endocrinology, Division of Translational Medicine, Sidra Medicine, Doha, Qatar
| | - Tomoshige Kino
- Laboratory of Molecular and Genomic Endocrinology, Division of Translational Medicine, Sidra Medicine, Doha, Qatar
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7
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Sanchis-Juan A, Bitsara C, Low KY, Carss KJ, French CE, Spasic-Boskovic O, Jarvis J, Field M, Raymond FL, Grozeva D. Rare Genetic Variation in 135 Families With Family History Suggestive of X-Linked Intellectual Disability. Front Genet 2019; 10:578. [PMID: 31316545 PMCID: PMC6609311 DOI: 10.3389/fgene.2019.00578] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Accepted: 06/03/2019] [Indexed: 01/08/2023] Open
Abstract
Families with multiple male children with intellectual disability (ID) are usually suspected of having disease due to a X-linked mode of inheritance and genetic studies focus on analysis of segregating variants in X-linked genes. However, the genetic cause of ID remains elusive in approximately 50% of affected individuals. Here, we report the analysis of next-generation sequencing data in 274 affected individuals from 135 families with a family history suggestive of X-linked ID. Genetic diagnoses were obtained for 19% (25/135) of the families, and 24% (33/135) had a variant of uncertain significance. In 12% of cases (16/135), the variants were not shared within the family, suggesting genetic heterogeneity and phenocopies are frequent. Of all the families with reportable variants (43%, 58/135), we observed that 55% (32/58) were in X-linked genes, but 38% (22/58) were in autosomal genes, while the remaining 7% (4/58) had multiple variants in genes with different modes on inheritance. This study highlights that in families with multiple affected males, X linkage should not be assumed, and both individuals should be considered, as different genetic etiologies are common in apparent familial cases.
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Affiliation(s)
- Alba Sanchis-Juan
- Department of Haematology, NHS Blood and Transplant Centre, University of Cambridge, Cambridge, United Kingdom.,Cambridge University Hospitals NHS Foundation Trust, NIHR BioResource, Cambridge, United Kingdom
| | - Christina Bitsara
- Department of Medical Genetics, Cambridge Institute for Medical Research, University of Cambridge, Cambridge, United Kingdom
| | - Kay Yi Low
- Department of Medical Genetics, Cambridge Institute for Medical Research, University of Cambridge, Cambridge, United Kingdom
| | - Keren J Carss
- Department of Haematology, NHS Blood and Transplant Centre, University of Cambridge, Cambridge, United Kingdom.,Cambridge University Hospitals NHS Foundation Trust, NIHR BioResource, Cambridge, United Kingdom
| | - Courtney E French
- Cambridge University Hospitals NHS Foundation Trust, NIHR BioResource, Cambridge, United Kingdom.,Department of Medical Genetics, Cambridge Institute for Medical Research, University of Cambridge, Cambridge, United Kingdom
| | - Olivera Spasic-Boskovic
- East Anglian Medical Genetics Service, Cambridge University Hospital, Cambridge, United Kingdom
| | - Joanna Jarvis
- Clinical Genetics Unit, Birmingham Women's NHS Foundation Trust, Birmingham, United Kingdom
| | - Michael Field
- Genetics of Learning Disability Service (Hunter Genetics), Waratah, NSW, Australia
| | - F Lucy Raymond
- Cambridge University Hospitals NHS Foundation Trust, NIHR BioResource, Cambridge, United Kingdom.,Department of Medical Genetics, Cambridge Institute for Medical Research, University of Cambridge, Cambridge, United Kingdom
| | - Detelina Grozeva
- Department of Medical Genetics, Cambridge Institute for Medical Research, University of Cambridge, Cambridge, United Kingdom
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8
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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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9
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Lumaka A, Race V, Peeters H, Corveleyn A, Coban-Akdemir Z, Jhangiani SN, Song X, Mubungu G, Posey J, Lupski JR, Vermeesch JR, Lukusa P, Devriendt K. A comprehensive clinical and genetic study in 127 patients with ID in Kinshasa, DR Congo. Am J Med Genet A 2018; 176:1897-1909. [PMID: 30088852 DOI: 10.1002/ajmg.a.40382] [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] [Received: 05/26/2018] [Accepted: 06/06/2018] [Indexed: 12/21/2022]
Abstract
Pathogenic variants account for 4 to 41% of patients with intellectual disability (ID) or developmental delay (DD). In Sub-Saharan Africa, the prevalence of ID is thought to be higher, but data in Central Africa are limited to some case reports. In addition, clinical descriptions of some syndromes are not available for this population. This study aimed at providing an estimate for the fraction of ID/DD for which an underlying etiological genetic cause may be elucidated and provide insights into their clinical presentation in special institutions in a Central African country. A total of 127 patients (33 females and 94 males, mean age 10.03 ± 4.68 years), were recruited from six institutions across Kinshasa. A clinical diagnosis was achieved in 44 but molecular confirmation was achieved in 21 of the 22 patients with expected genetic defect (95% clinical sensitivity). Identified diseases included Down syndrome (15%), submicroscopic copy number variants (9%), aminoacylase deficiency (0.8%), Partington syndrome in one patient (0.8%) and his similarly affected brother, X-linked syndromic Mental Retardation type 33 (0.8%), and two conditions without clear underlying molecular genetic etiologies (Oculo-Auriculo-Vertebral and Amniotic Bands Sequence). We have shown that genetic etiologies, similar to those reported in Caucasian subjects, are a common etiologic cause of ID in African patients from Africa. We have confirmed the diagnostic utility of clinical characterization prior to genetic testing. Finally, our clinical descriptions provide insights into the presentation of these genetic diseases in African patients.
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Affiliation(s)
- Aimé Lumaka
- Centre for Human Genetics, Faculty of Medicine, University of Kinshasa, Kinshasa, DR, Congo.,Département des Sciences Biomédicales et Précliniques, GIGA-R, Laboratoire de Génétique Humaine, University of Liège, Liège, Belgium.,Institut National de Recherche Biomédicale, Kinshasa, DR, Congo.,Department of Pediatrics, Faculty of Medicine, University of Kinshasa, Kinshasa, DR, Congo
| | - Valerie Race
- Centre for Human Genetics, University Hospital, University of Leuven, Leuven, Belgium
| | - Hilde Peeters
- Centre for Human Genetics, University Hospital, University of Leuven, Leuven, Belgium
| | - Anniek Corveleyn
- Centre for Human Genetics, University Hospital, University of Leuven, Leuven, Belgium
| | - Zeynep Coban-Akdemir
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
| | - Shalini N Jhangiani
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
| | - Xiaofei Song
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
| | - Gerrye Mubungu
- Centre for Human Genetics, Faculty of Medicine, University of Kinshasa, Kinshasa, DR, Congo.,Institut National de Recherche Biomédicale, Kinshasa, DR, Congo.,Department of Pediatrics, Faculty of Medicine, University of Kinshasa, Kinshasa, DR, Congo.,Centre for Human Genetics, University Hospital, University of Leuven, Leuven, Belgium
| | - Jennifer Posey
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, Texas
| | - James R Lupski
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas.,Human Genome Sequencing Center, Baylor College of Medicine, Houston, Texas.,Department of Pediatrics, Baylor College of Medicine, Houston, Texas.,Genetics Clinic service, Texas Children's Hospital, Houston, Texas
| | - Joris R Vermeesch
- Centre for Human Genetics, University Hospital, University of Leuven, Leuven, Belgium
| | - Prosper Lukusa
- Centre for Human Genetics, Faculty of Medicine, University of Kinshasa, Kinshasa, DR, Congo.,Département des Sciences Biomédicales et Précliniques, GIGA-R, Laboratoire de Génétique Humaine, University of Liège, Liège, Belgium.,Institut National de Recherche Biomédicale, Kinshasa, DR, Congo.,Centre for Human Genetics, University Hospital, University of Leuven, Leuven, Belgium
| | - Koenraad Devriendt
- Centre for Human Genetics, University Hospital, University of Leuven, Leuven, Belgium
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10
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Lubala TK, Lumaka A, Kanteng G, Mutesa L, Mukuku O, Wembonyama S, Hagerman R, Luboya ON, Lukusa Tshilobo P. Fragile X checklists: A meta-analysis and development of a simplified universal clinical checklist. Mol Genet Genomic Med 2018; 6:526-532. [PMID: 29624914 PMCID: PMC6081230 DOI: 10.1002/mgg3.398] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Revised: 03/06/2018] [Accepted: 03/06/2018] [Indexed: 02/05/2023] Open
Abstract
BACKGROUND Clinical checklists available have been developed to assess the risk of a positive Fragile X syndrome but they include relatively small sample sizes. Therefore, we carried out a meta-analysis that included statistical pooling of study results to obtain accurate figures on the prevalence of clinical predictors of Fragile X syndrome among patients with intellectual disability, thereby helping health professionals to improve their referrals for Fragile X testing. METHODS All published studies consisting of cytogenetic and/or molecular screening for fragile X syndrome among patients with intellectual disability, were eligible for the meta-analysis. All patients enrolled in clinical checklists trials of Fragile X syndrome were eligible for this review, with no exclusion based on ethnicity or age. Odds ratio values, with 95% confidence intervals as well as Cronbach coefficient alpha, was reported to assess the frequency of clinical characteristics in subjects with intellectual disability with and without the fragile X mutation to determine the most discriminating. RESULTS The following features were strongly associated with Fragile X syndrome: skin soft and velvety on the palms with redundancy of skin on the dorsum of hand [OR: 16.85 (95% CI 10.4-27.3; α:0.97)], large testes [OR: 7.14 (95% CI 5.53-9.22; α: 0.80)], large and prominent ears [OR: 18.62 (95% CI 14.38-24.1; α: 0.98)], pale blue eyes [OR: 8.97 (95% CI 4.75-16.97; α: 0.83)], family history of intellectual disability [OR: 3.43 (95% CI 2.76-4.27; α: 0.81)] as well as autistic-like behavior [OR: 3.08 (95% CI 2.48-3.83; α: 0.77)], Flat feet [OR: 11.53 (95% CI 6.79-19.56; α:0.91)], plantar crease [OR: 3.74 (95% CI 2.67-5.24; α: 0.70)]. We noted a weaker positive association between transverse palmar crease [OR: 2.68 (95% CI 1.70-4.18; α: 0.51)], elongated face [OR: 3.69 (95% CI 2.84-4.81; α: 0.63)]; hyperextensible metacarpo-phalangeal joints [OR: 2.68 (95% CI 2.15-3.34; α: 0.57)] and the Fragile X syndrome. CONCLUSION This study has identified the highest risk features for patients with Fragile X syndrome that have been used to design a universal clinical checklist.
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Affiliation(s)
- Toni Kasole Lubala
- Division of Dysmorphology & Birth DefectsDepartment of PediatricsUniversity of LubumbashiLubumbashiCongo
| | - Aimé Lumaka
- Faculté de MédecineDépartement de PédiatrieUniversité de KinshasaKinshasaCongo
- Centre de Génétique HumaineInstitut National de Recherche BiomédicaleKinshasaCongo
| | - Gray Kanteng
- Division of Dysmorphology & Birth DefectsDepartment of PediatricsUniversity of LubumbashiLubumbashiCongo
| | - Léon Mutesa
- Center for Human GeneticsSchool of Medicine and PharmacyCollege of Medicine and Health SciencesUniversity of RwandaKigaliRwanda
| | - Olivier Mukuku
- Département de PédiatrieInstitut Supérieur des Techniques MédicalesLubumbashiCongo
| | - Stanislas Wembonyama
- Division of Dysmorphology & Birth DefectsDepartment of PediatricsUniversity of LubumbashiLubumbashiCongo
| | - Randi Hagerman
- MIND InstituteUniversity of California DavisSacramentoCAUSA
- Department of PediatricsUniversity of California Davis Medical CenterSacramentoCAUSA
| | - Oscar Numbi Luboya
- Division of Dysmorphology & Birth DefectsDepartment of PediatricsUniversity of LubumbashiLubumbashiCongo
| | - Prosper Lukusa Tshilobo
- Faculté de MédecineDépartement de PédiatrieUniversité de KinshasaKinshasaCongo
- Centre de Génétique HumaineInstitut National de Recherche BiomédicaleKinshasaCongo
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11
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Wang B, Ji T, Zhou X, Wang J, Wang X, Wang J, Zhu D, Zhang X, Sham PC, Zhang X, Ma X, Jiang Y. CNV analysis in Chinese children of mental retardation highlights a sex differentiation in parental contribution to de novo and inherited mutational burdens. Sci Rep 2016; 6:25954. [PMID: 27257017 PMCID: PMC4891738 DOI: 10.1038/srep25954] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Accepted: 04/06/2016] [Indexed: 12/28/2022] Open
Abstract
Rare copy number variations (CNVs) are a known genetic etiology in neurodevelopmental disorders (NDD). Comprehensive CNV analysis was performed in 287 Chinese children with mental retardation and/or development delay (MR/DD) and their unaffected parents. When compared with 5,866 ancestry-matched controls, 11~12% more MR/DD children carried rare and large CNVs. The increased CNV burden in MR/DD was predominantly due to de novo CNVs, the majority of which (62%) arose in the paternal germline. We observed a 2~3 fold increase of large CNV burden in the mothers of affected children. By implementing an evidence-based review approach, pathogenic structural variants were identified in 14.3% patients and 2.4% parents, respectively. Pathogenic CNVs in parents were all carried by mothers. The maternal transmission bias of deleterious CNVs was further replicated in a published dataset. Our study confirms the pathogenic role of rare CNVs in MR/DD, and provides additional evidence to evaluate the dosage sensitivity of some candidate genes. It also supports a population model of MR/DD that spontaneous mutations in males' germline are major contributor to the de novo mutational burden in offspring, with higher penetrance in male than female; unaffected carriers of causative mutations, mostly females, then contribute to the inherited mutational burden.
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Affiliation(s)
- Binbin Wang
- Department of Pediatrics, Peking University First Hospital, Beijing, China.,National Research Institute of Family Planning, Beijing, China
| | - Taoyun Ji
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Xueya Zhou
- MOE Key Laboratory of Bioinformatics, Bioinformatics Division and Center for Synthetic and Systems Biology, TNLIST/Department of Automation, Tsinghua University, Beijing, China.,Department of Psychiatry and Centre for Genomic Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China
| | - Jing Wang
- Department of Medical Genetics, The Capital Medical University, Beijing, China
| | - Xi Wang
- National Research Institute of Family Planning, Beijing, China
| | - Jingmin Wang
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | | | - Xuejun Zhang
- Institute of Dermatology and Department of Dermatology at No.1 Hospital, Anhui Medical University, Heifei, Anhui, China
| | - Pak Chung Sham
- Department of Psychiatry and Centre for Genomic Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China
| | - Xuegong Zhang
- MOE Key Laboratory of Bioinformatics, Bioinformatics Division and Center for Synthetic and Systems Biology, TNLIST/Department of Automation, Tsinghua University, Beijing, China
| | - Xu Ma
- National Research Institute of Family Planning, Beijing, China
| | - Yuwu Jiang
- Department of Pediatrics, Peking University First Hospital, Beijing, China
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12
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Leung C, Jia Z. Mouse Genetic Models of Human Brain Disorders. Front Genet 2016; 7:40. [PMID: 27047540 PMCID: PMC4803727 DOI: 10.3389/fgene.2016.00040] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Accepted: 03/08/2016] [Indexed: 01/29/2023] Open
Abstract
Over the past three decades, genetic manipulations in mice have been used in neuroscience as a major approach to investigate the in vivo function of genes and their alterations. In particular, gene targeting techniques using embryonic stem cells have revolutionized the field of mammalian genetics and have been at the forefront in the generation of numerous mouse models of human brain disorders. In this review, we will first examine childhood developmental disorders such as autism, intellectual disability, Fragile X syndrome, and Williams-Beuren syndrome. We will then explore psychiatric disorders such as schizophrenia and lastly, neurodegenerative disorders including Alzheimer’s disease and Parkinson’s disease. We will outline the creation of these mouse models that range from single gene deletions, subtle point mutations to multi-gene manipulations, and discuss the key behavioral phenotypes of these mice. Ultimately, the analysis of the models outlined in this review will enhance our understanding of the in vivo role and underlying mechanisms of disease-related genes in both normal brain function and brain disorders, and provide potential therapeutic targets and strategies to prevent and treat these diseases.
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Affiliation(s)
- Celeste Leung
- The Hospital for Sick Children, Program in Neurosciences and Mental Health, Peter Gilgan Centre for Research and Learning, TorontoON, Canada; Program in Physiology, University of Toronto, TorontoON, Canada
| | - Zhengping Jia
- The Hospital for Sick Children, Program in Neurosciences and Mental Health, Peter Gilgan Centre for Research and Learning, TorontoON, Canada; Program in Physiology, University of Toronto, TorontoON, Canada
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13
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Craig IW, Haworth CMA, Plomin R. Commentary on "A Role for the X Chromosome in Sex Differences in Variability in General Intelligence?" (Johnson et al., 2009). PERSPECTIVES ON PSYCHOLOGICAL SCIENCE 2015; 4:615-21. [PMID: 26161737 DOI: 10.1111/j.1745-6924.2009.01170.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Johnson et al.'s (2009) article highlights the role of X-chromosomal genes in general intelligence and draws attention to their potential role in explaining the observed greater variance for this trait in males and their excess at both extremes of the distribution. We note that this would result from a simple additive effect of X-linked intelligence genes and also discuss the potentially important contribution of recessive deleterious loci. The buffering effect of heterozygosity in females will be partly constrained by the skewing of X-inactivation patterns increasing the variance of females beyond what is expected. Furthermore, escape of some X-linked genes from in-activation may also be relevant to male-female variance comparisons. We also comment on the difficulty of establishing the extent to which the X chromosome is enriched for intelligence genes and point out that their estimates of the proportion of genes influencing general intelligence that might be located on the X chromosome rely on some doubtful premises, especially concerning the likely equivalence of X-linked gene action in males and females. Finally, we discuss the increasingly compelling evidence for the accumulation of genes on the X chromosome that have selective benefit to males, including those implicated infertility and some manifestations of intelligence.
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Affiliation(s)
- Ian W Craig
- Social, Genetic, and Developmental Psychiatry Centre, Institute of Psychiatry, London, United Kingdom
| | - Claire M A Haworth
- Social, Genetic, and Developmental Psychiatry Centre, Institute of Psychiatry, London, United Kingdom
| | - Robert Plomin
- Social, Genetic, and Developmental Psychiatry Centre, Institute of Psychiatry, London, United Kingdom
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14
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Preiksaitiene E, Caro A, Benušienė E, Oltra S, Orellana C, Morkūnienė A, Roselló MP, Kasnauskiene J, Monfort S, Kučinskas V, Mayo S, Martinez F. A novel missense mutation in the NSDHL gene identified in a Lithuanian family by targeted next-generation sequencing causes CK syndrome. Am J Med Genet A 2015; 167:1342-8. [PMID: 25900314 DOI: 10.1002/ajmg.a.36999] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2015] [Accepted: 01/15/2015] [Indexed: 12/27/2022]
Abstract
The NSDHL gene encodes 3β-hydroxysteroid dehydrogenase involved in one of the later steps of the cholesterol biosynthetic pathway. Mutations in this gene can cause CHILD syndrome (OMIM 308050) and CK syndrome (OMIM 300831). CHILD syndrome is an X-linked dominant, male lethal disorder caused by mutations in the NSDHL gene that result in the loss of the function of the NSDHL protein. CK syndrome is an allelic X-linked recessive disorder. So far, 13 patients with CK syndrome from two families have been reported on. We present a new five-generation family with affected males manifesting clinical features of CK syndrome. Next generation sequencing was targeted to a custom panel of 542 genes with known or putative implication on intellectual disability. Missense mutation p.Gly152Asp was identified in the NSDHL gene in the DNA sample of the affected male. Mutation carrier status was confirmed for all the obligate carriers in the family. The clinical features of the affected males in the family manifested as weak fetal movements, severe intellectual disability, seizures, spasticity, atrophy of optic discs, microcephaly, plagiocephaly, skeletal abnormalities, and minor facial anomalies, including a high nasal bridge, strabismus, and micrognathia. A highly significant preferential transmission of the mutation was observed in this and previous families segregating CK syndrome. Our report expands the clinical spectrum of this syndrome to include weak fetal movements, spasticity, and plagiocephaly, and transmission ratio distortion. The various findings in these patients increase our understanding of the diversity of the clinical presentation of cholesterol biosynthesis disorders.
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Affiliation(s)
- Egle Preiksaitiene
- Department of Human and Medical Genetics, Faculty of Medicine, Vilnius University, Vilnius, Lithuania
| | - Alfonso Caro
- Unidad de Genética, Grupo de Investigación Traslacional en Genética, Hospital Universitario y Politécnico La Fe, Valencia, Spain
| | - Eglė Benušienė
- Department of Human and Medical Genetics, Faculty of Medicine, Vilnius University, Vilnius, Lithuania
| | - Silvestre Oltra
- Unidad de Genética, Grupo de Investigación Traslacional en Genética, Hospital Universitario y Politécnico La Fe, Valencia, Spain
| | - Carmen Orellana
- Unidad de Genética, Grupo de Investigación Traslacional en Genética, Hospital Universitario y Politécnico La Fe, Valencia, Spain
| | - Aušra Morkūnienė
- Department of Human and Medical Genetics, Faculty of Medicine, Vilnius University, Vilnius, Lithuania
| | - Mónica Pilar Roselló
- Unidad de Genética, Grupo de Investigación Traslacional en Genética, Hospital Universitario y Politécnico La Fe, Valencia, Spain
| | - Jurate Kasnauskiene
- Department of Human and Medical Genetics, Faculty of Medicine, Vilnius University, Vilnius, Lithuania
| | - Sandra Monfort
- Unidad de Genética, Grupo de Investigación Traslacional en Genética, Hospital Universitario y Politécnico La Fe, Valencia, Spain
| | - Vaidutis Kučinskas
- Department of Human and Medical Genetics, Faculty of Medicine, Vilnius University, Vilnius, Lithuania
| | - Sonia Mayo
- Unidad de Genética, Grupo de Investigación Traslacional en Genética, Hospital Universitario y Politécnico La Fe, Valencia, Spain
| | - Francisco Martinez
- Unidad de Genética, Grupo de Investigación Traslacional en Genética, Hospital Universitario y Politécnico La Fe, Valencia, Spain
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15
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Dufke A, Riess O. Präkonzeptionelle und vorgeburtliche klinische Genomsequenzierung. MED GENET-BERLIN 2014. [DOI: 10.1007/s11825-014-0023-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Zusammenfassung
Hintergrund
Innerhalb kürzester Zeit haben Hochdurchsatzanalysen von Exomen und Genomen Eingang in die postnatale klinisch-diagnostische Anwendung gefunden. Bei hoher technischer Analysezuverlässigkeit, sinkenden Kosten und kurzen Analysezeiten ist das Potenzial, welches sich für diese Anwendung auch für das präkonzeptionelle Screening und die Pränataldiagnostik ergeben könnte, offensichtlich. Insbesondere diese beiden Anwendungsgebiete erfordern eine sehr hohe Sicherheit in der klinischen Befundinterpretation. Eine weitere Herausforderung gegenüber der postnatalen diagnostischen Anwendung wird die Beurteilung des klinischen Manifestationsspektrums präklinisch oder pränatal erhobener genomischer Sequenzdaten sein.
Material und Methoden
Abgeleitet von den Erfahrungen mit NGS-Analysen im postnatalen diagnostischen Ansatz erfolgen eine Übertragung und ein Ausblick auf die Anwendung der Methode im Kontext der Familienplanung.
Diskussion und Ergebnisse
Der Beitrag beschränkt sich auf die technische und klinische Anwendbarkeit. Diskutiert werden der Einsatz von NGS als umfassende Screeningmethode von Populationen, Niedrigrisikokollektiven und die Beschränkung auf ausgewählte, dem individuellen Risikoprofil angepasste Analysen. Letztere könnten kurz- bis mittelfristig Eingang in die präkonzeptionelle und auch vorgeburtliche Diagnostik finden.
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Affiliation(s)
- Andreas Dufke
- Aff1 grid.411544.1 0000000101968249 Institut für Medizinische Genetik und Angewandte Genomik Universitätsklinikum Tübingen Calwerstr. 7 72076 Tübingen Deutschland
| | - Olaf Riess
- Aff1 grid.411544.1 0000000101968249 Institut für Medizinische Genetik und Angewandte Genomik Universitätsklinikum Tübingen Calwerstr. 7 72076 Tübingen Deutschland
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16
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Redin C, Gérard B, Lauer J, Herenger Y, Muller J, Quartier A, Masurel-Paulet A, Willems M, Lesca G, El-Chehadeh S, Le Gras S, Vicaire S, Philipps M, Dumas M, Geoffroy V, Feger C, Haumesser N, Alembik Y, Barth M, Bonneau D, Colin E, Dollfus H, Doray B, Delrue MA, Drouin-Garraud V, Flori E, Fradin M, Francannet C, Goldenberg A, Lumbroso S, Mathieu-Dramard M, Martin-Coignard D, Lacombe D, Morin G, Polge A, Sukno S, Thauvin-Robinet C, Thevenon J, Doco-Fenzy M, Genevieve D, Sarda P, Edery P, Isidor B, Jost B, Olivier-Faivre L, Mandel JL, Piton A. Efficient strategy for the molecular diagnosis of intellectual disability using targeted high-throughput sequencing. J Med Genet 2014; 51:724-36. [PMID: 25167861 PMCID: PMC4215287 DOI: 10.1136/jmedgenet-2014-102554] [Citation(s) in RCA: 197] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Background Intellectual disability (ID) is characterised by an extreme genetic heterogeneity. Several hundred genes have been associated to monogenic forms of ID, considerably complicating molecular diagnostics. Trio-exome sequencing was recently proposed as a diagnostic approach, yet remains costly for a general implementation. Methods We report the alternative strategy of targeted high-throughput sequencing of 217 genes in which mutations had been reported in patients with ID or autism as the major clinical concern. We analysed 106 patients with ID of unknown aetiology following array-CGH analysis and other genetic investigations. Ninety per cent of these patients were males, and 75% sporadic cases. Results We identified 26 causative mutations: 16 in X-linked genes (ATRX, CUL4B, DMD, FMR1, HCFC1, IL1RAPL1, IQSEC2, KDM5C, MAOA, MECP2, SLC9A6, SLC16A2, PHF8) and 10 de novo in autosomal-dominant genes (DYRK1A, GRIN1, MED13L, TCF4, RAI1, SHANK3, SLC2A1, SYNGAP1). We also detected four possibly causative mutations (eg, in NLGN3) requiring further investigations. We present detailed reasoning for assigning causality for each mutation, and associated patients’ clinical information. Some genes were hit more than once in our cohort, suggesting they correspond to more frequent ID-associated conditions (KDM5C, MECP2, DYRK1A, TCF4). We highlight some unexpected genotype to phenotype correlations, with causative mutations being identified in genes associated to defined syndromes in patients deviating from the classic phenotype (DMD, TCF4, MECP2). We also bring additional supportive (HCFC1, MED13L) or unsupportive (SHROOM4, SRPX2) evidences for the implication of previous candidate genes or mutations in cognitive disorders. Conclusions With a diagnostic yield of 25% targeted sequencing appears relevant as a first intention test for the diagnosis of ID, but importantly will also contribute to a better understanding regarding the specific contribution of the many genes implicated in ID and autism.
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Affiliation(s)
- Claire Redin
- Département de Médicine translationnelle et Neurogénétique, IGBMC, CNRS UMR 7104/INSERM U964/Université de Strasbourg, Illkirch, France Chaire de Génétique Humaine, Collège de France, Illkirch, France
| | - Bénédicte Gérard
- Laboratoire de diagnostic génétique, Hôpitaux Universitaires de Strasbourg, Strasbourg, France
| | - Julia Lauer
- Laboratoire de diagnostic génétique, Hôpitaux Universitaires de Strasbourg, Strasbourg, France
| | - Yvan Herenger
- Laboratoire de diagnostic génétique, Hôpitaux Universitaires de Strasbourg, Strasbourg, France
| | - Jean Muller
- Département de Médicine translationnelle et Neurogénétique, IGBMC, CNRS UMR 7104/INSERM U964/Université de Strasbourg, Illkirch, France Laboratoire de diagnostic génétique, Hôpitaux Universitaires de Strasbourg, Strasbourg, France
| | - Angélique Quartier
- Département de Médicine translationnelle et Neurogénétique, IGBMC, CNRS UMR 7104/INSERM U964/Université de Strasbourg, Illkirch, France Chaire de Génétique Humaine, Collège de France, Illkirch, France
| | - Alice Masurel-Paulet
- Centre de Génétique et Centre de Référence Anomalies du développement et Syndromes malformatifs, Hôpital d'Enfants, CHU de Dijon, Dijon, France
| | - Marjolaine Willems
- Département de Génétique Médicale, Centre de Référence Maladies Rares Anomalies du Développement et Syndromes Malformatifs Sud-Languedoc Roussillon, Hôpital Arnaud de Villeneuve, Montpellier, France
| | - Gaétan Lesca
- Département de Génétique Médicale, Hospices Civils de Lyon, Bron, France
| | - Salima El-Chehadeh
- Centre de Génétique et Centre de Référence Anomalies du développement et Syndromes malformatifs, Hôpital d'Enfants, CHU de Dijon, Dijon, France
| | - Stéphanie Le Gras
- Plateforme de Biopuces et Séquençage, IGBMC, CNRS UMR 7104/INSERM U964/Université de Strasbourg, Illkirch, France
| | - Serge Vicaire
- Plateforme de Biopuces et Séquençage, IGBMC, CNRS UMR 7104/INSERM U964/Université de Strasbourg, Illkirch, France
| | - Muriel Philipps
- Plateforme de Biopuces et Séquençage, IGBMC, CNRS UMR 7104/INSERM U964/Université de Strasbourg, Illkirch, France
| | - Michaël Dumas
- Plateforme de Biopuces et Séquençage, IGBMC, CNRS UMR 7104/INSERM U964/Université de Strasbourg, Illkirch, France
| | - Véronique Geoffroy
- Plateforme de Bioinformatique de Strasbourg (BIPS), IGBMC, CNRS UMR 7104/INSERM U964/Université de Strasbourg, Illkirch, France
| | - Claire Feger
- Plateforme de Biopuces et Séquençage, IGBMC, CNRS UMR 7104/INSERM U964/Université de Strasbourg, Illkirch, France
| | - Nicolas Haumesser
- Département de Médicine translationnelle et Neurogénétique, IGBMC, CNRS UMR 7104/INSERM U964/Université de Strasbourg, Illkirch, France Chaire de Génétique Humaine, Collège de France, Illkirch, France
| | - Yves Alembik
- Département de Génétique, CHU de Hautepierre, Strasbourg, France
| | - Magalie Barth
- Départment de Biochimie et de Génétique, CHU d'Angers, Angers, France
| | - Dominique Bonneau
- Départment de Biochimie et de Génétique, CHU d'Angers, Angers, France
| | - Estelle Colin
- Départment de Biochimie et de Génétique, CHU d'Angers, Angers, France
| | - Hélène Dollfus
- Laboratoire de Génétique Médicale, INSERM U1112, Faculté de Médecine de Strasbourg, Hôpitaux Universitaires de Strasbourg, Strasbourg, France
| | - Bérénice Doray
- Département de Génétique, CHU de Hautepierre, Strasbourg, France
| | - Marie-Ange Delrue
- CHU de Bordeaux, Génétique Médicale, Université de Bordeaux, Laboratoire MRGM, Bordeaux, France
| | | | - Elisabeth Flori
- Département de Génétique, CHU de Hautepierre, Strasbourg, France
| | - Mélanie Fradin
- Service de Génétique Médicale, Centre De Référence Anomalies du Développement, CHU de Rennes, Rennes, France
| | | | | | | | | | | | - Didier Lacombe
- CHU de Bordeaux, Génétique Médicale, Université de Bordeaux, Laboratoire MRGM, Bordeaux, France
| | - Gilles Morin
- Unité de Génétique Clinique, CHU d'Amiens, Amiens, France
| | - Anne Polge
- Laboratoire de Biochimie, CHU de Nîmes, Nîmes, France
| | - Sylvie Sukno
- Service de Neuropédiatrie, Hôpital Saint Vincent de Paul, Groupe Hospitalier de l'Institut Catholique Lillois, Faculté Libre de Médecine, Lille, France
| | - Christel Thauvin-Robinet
- Centre de Génétique et Centre de Référence Anomalies du développement et Syndromes malformatifs, Hôpital d'Enfants, CHU de Dijon, Dijon, France
| | - Julien Thevenon
- Centre de Génétique et Centre de Référence Anomalies du développement et Syndromes malformatifs, Hôpital d'Enfants, CHU de Dijon, Dijon, France
| | | | - David Genevieve
- Département de Génétique Médicale, Centre de Référence Maladies Rares Anomalies du Développement et Syndromes Malformatifs Sud-Languedoc Roussillon, Hôpital Arnaud de Villeneuve, Montpellier, France
| | - Pierre Sarda
- Département de Génétique Médicale, Centre de Référence Maladies Rares Anomalies du Développement et Syndromes Malformatifs Sud-Languedoc Roussillon, Hôpital Arnaud de Villeneuve, Montpellier, France
| | - Patrick Edery
- Département de Génétique Médicale, Hospices Civils de Lyon, Bron, France
| | - Bertrand Isidor
- Service de Génétique Médicale, CHU de Nantes, Nantes, France
| | - Bernard Jost
- Plateforme de Biopuces et Séquençage, IGBMC, CNRS UMR 7104/INSERM U964/Université de Strasbourg, Illkirch, France
| | - Laurence Olivier-Faivre
- Centre de Génétique et Centre de Référence Anomalies du développement et Syndromes malformatifs, Hôpital d'Enfants, CHU de Dijon, Dijon, France
| | - Jean-Louis Mandel
- Département de Médicine translationnelle et Neurogénétique, IGBMC, CNRS UMR 7104/INSERM U964/Université de Strasbourg, Illkirch, France Chaire de Génétique Humaine, Collège de France, Illkirch, France Laboratoire de diagnostic génétique, Hôpitaux Universitaires de Strasbourg, Strasbourg, France
| | - Amélie Piton
- Département de Médicine translationnelle et Neurogénétique, IGBMC, CNRS UMR 7104/INSERM U964/Université de Strasbourg, Illkirch, France Chaire de Génétique Humaine, Collège de France, Illkirch, France
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17
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Jacquemont S, Coe B, Hersch M, Duyzend M, Krumm N, Bergmann S, Beckmann J, Rosenfeld J, Eichler E. A higher mutational burden in females supports a "female protective model" in neurodevelopmental disorders. Am J Hum Genet 2014; 94:415-25. [PMID: 24581740 DOI: 10.1016/j.ajhg.2014.02.001] [Citation(s) in RCA: 364] [Impact Index Per Article: 36.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2013] [Accepted: 02/03/2014] [Indexed: 12/30/2022] Open
Abstract
Increased male prevalence has been repeatedly reported in several neurodevelopmental disorders (NDs), leading to the concept of a "female protective model." We investigated the molecular basis of this sex-based difference in liability and demonstrated an excess of deleterious autosomal copy-number variants (CNVs) in females compared to males (odds ratio [OR] = 1.46, p = 8 × 10(-10)) in a cohort of 15,585 probands ascertained for NDs. In an independent autism spectrum disorder (ASD) cohort of 762 families, we found a 3-fold increase in deleterious autosomal CNVs (p = 7 × 10(-4)) and an excess of private deleterious single-nucleotide variants (SNVs) in female compared to male probands (OR = 1.34, p = 0.03). We also showed that the deleteriousness of autosomal SNVs was significantly higher in female probands (p = 0.0006). A similar bias was observed in parents of probands ascertained for NDs. Deleterious CNVs (>400 kb) were maternally inherited more often (up to 64%, p = 10(-15)) than small CNVs < 400 kb (OR = 1.45, p = 0.0003). In the ASD cohort, increased maternal transmission was also observed for deleterious CNVs and SNVs. Although ASD females showed higher mutational burden and lower cognition, the excess mutational burden remained, even after adjustment for those cognitive differences. These results strongly suggest that females have an increased etiological burden unlinked to rare deleterious variants on the X chromosome. Carefully phenotyped and genotyped cohorts will be required for identifying the symptoms, which show gender-specific liability to mutational burden.
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18
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Maris AF, Barbato IT, Trott A, Montano MAE. Familial mental retardation: a review and practical classification. CIENCIA & SAUDE COLETIVA 2013. [DOI: 10.1590/s1413-81232013000600023] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Mental retardation (MR) is a definition which comprises a series of conditions whose common feature is an intellectual handicap that develops before the age of 18, afflicting 2-3% of the world's population. The classification of MR into different categories is determined by the extent of the handicap instead of its cause, which often remains unrecognized. Sometimes, MR runs in a family, characterizing familial MR, and those cases permit an in-depth look into the genetic causes and consequences of the problem. However, almost no work is available on the prevalence of familial MR among the registered MR cases, possibly because familial MR is a term with no clear definition. The scope of this work is to review the topic and discuss the implications of different genetic and environmental factors, which characterize particular categories of familial cases, suggesting a practical classification of familial MR, which is important for epidemiologic studies and also for counseling in the clinic. Some of the aspects are discussed under the perspective of a newly-developed country like Brazil.
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Abstract
Ten percent of cases of intellectual deficiency in boys are caused by genes located on the X chromosome. X-linked mental retardation (XLMR) includes more than 200 syndromes and 80 genes identified to date. The fragile X syndrome is the most frequent syndrome, due to a dynamic mutation with a CGG triplet amplification. Mental retardation is virtually always present. Phonological and syntactic impairments are often combined with pragmatic language impairment and visuospatial reasoning difficulties. A minority fulfill the criteria for autism. In girls, the clinical expression of the complete mutation varies according to the X chromosome inactivation profile. Several XLMR occur as severe early onset encephalopathies: Lowe oculocerebrorenal syndrome, ATR-X syndrome (alpha thalassemia/mental retardation X-linked), Allan-Herdon-Dudley syndrome (MCT8 gene). Two genes, ARX (X-LAG; Partington syndrome) and MECP2 (Rett syndrome in females; mild MR with spastic diplegia/psychotic problems in males) are associated with various phenotypes, according to the mutation involved. Oligophrenine 1 (OPHN-1) gene mutations lead to vermal dysplasia. PQBP1 gene mutations (Renpenning syndrome) are responsible for moderate to severe mental deficiency, microcephaly, and small stature. Although some forms of XLMR are not very specific and the phenotype for each given gene is somewhat heterogeneous, a clinical diagnostic strategy is emerging.
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Affiliation(s)
- Vincent des Portes
- Reference Center for Fragile X and other X-linked Intellectual Disabilities and Department of Pediatric Neurology, Hôpital Femme Mère Enfant, CHU de Lyon, Lyon, France.
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Trabelsi M, Chelly I, Maazoul F, Chaabouni M, Ouertani I, Kraoua L, Khemakhem L, Mrad R, Chaabouni H. Epidemiologic and clinical characteristics of 458 Tunisian patients with intellectual deficiency and a reconsidered diagnostic strategy. Eur J Med Genet 2012; 56:13-9. [PMID: 23142735 DOI: 10.1016/j.ejmg.2012.10.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2012] [Accepted: 10/10/2012] [Indexed: 11/28/2022]
Abstract
Intellectual Deficiency (ID) is a common neuropsychiatric disorder whose etiopathogenesis still insufficiently understood. In the last decade, several surveys, assessing epidemiologic, clinical and etiologic parameters of ID, have been performed but none of them is realized in a Tunisian population. In this retrospective survey, we propose to study these parameters, in a Tunisian cohort of 458 patients with constitutional ID, and to assess our diagnostic strategy. Data analyses, by the SPSS program, reveal a male predominance, a high level of consanguinity, an advanced mean age of patients, a rare frequentation of specialized institutions by the severely affected patients, and a high frequency of familial forms with predominance of the recessive autosomal ones. The study of clinical parameters and investigations' results shows that 72.1% of our patients present a syndromic ID. For these patients, chromosomal anomalies are rarely described, EEG anomalies were usually non-specific in patients without clinical evidence of epilepsy, and brain anomalies are common in patients with severe ID, neurological symptoms or history of seizures. Aetiology is identified in 13.1% of them whereas it is still unknown in 100% of patients with non-specific ID. This study allows us to better characterize, epidemiologically and clinically, the first large Tunisian cohort of patients with ID and to assess our diagnostic strategy in order to propose a revised one that will improve the diagnostic lead, the care chain and the preventive resources of ID.
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Affiliation(s)
- Mediha Trabelsi
- Charles Nicolle Hospital, Congenital and Hereditary Diseases Tunis, Tunisia.
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21
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Willemsen MH, de Leeuw N, de Brouwer AP, Pfundt R, Hehir-Kwa JY, Yntema HG, Nillesen WM, de Vries BB, van Bokhoven H, Kleefstra T. Interpretation of clinical relevance of X-chromosome copy number variations identified in a large cohort of individuals with cognitive disorders and/or congenital anomalies. Eur J Med Genet 2012; 55:586-98. [DOI: 10.1016/j.ejmg.2012.05.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2012] [Revised: 05/05/2012] [Accepted: 05/05/2012] [Indexed: 01/01/2023]
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Utine GE, Kiper PÖ, Alanay Y, Haliloğlu G, Aktaş D, Boduroğlu K, Tunçbilek E, Alikaşifoğlu M. Searching for Copy Number Changes in Nonsyndromic X-Linked Intellectual Disability. Mol Syndromol 2011; 2:64-71. [PMID: 22511893 DOI: 10.1159/000334289] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/27/2011] [Indexed: 11/19/2022] Open
Abstract
Intellectual disability (ID) has a prevalence of 2-3% with 0.3% of the population being severely retarded. Etiology is heterogeneous, owing to numerous genetic and environmental factors. Underlying etiology remains undetermined in 75-80% of mildly disabled patients and 20-50% of those severely disabled. Twelve percent of all ID is thought to be X-linked (XLID). This study covers copy number analysis of some of the known XLID genes, using multiplex ligation-dependent probe amplification (MLPA) in 100 nonsyndromic patients. One of the patients was found to have duplication in all exons of MECP2 gene, and another had duplication in the fifth exon of TM4SF2/TSPAN7 gene. Affymetrix® 6.0 whole-genome SNP microarray confirmed the duplication in MECP2 and showed duplication of exons 2-7 in TM4SF2/TSPAN7, respectively. MECP2 duplication has recently been recognized as a syndromic cause of XLID in males, whereas duplications in TM4SF2/TSPAN7 are yet to be determined as a cause of XLID. Being an efficient, rapid, easy-to-perform, easy-to-interpret, and cost-effective method of copy number analysis of specific DNA sequences, MLPA presents wide clinical utility and may be included in diagnostic workup of ID, particularly when microarrays are unavailable as a first-line approach.
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Affiliation(s)
- G E Utine
- Clinical Genetics Unit, Hacettepe University Faculty of Medicine, Ankara, Turkey
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23
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9 Mb familial duplication in chromosome band Xp22.2-22.13 associated with mental retardation, hypotonia and developmental delay, scoliosis, cardiovascular problems and mild dysmorphic facial features. Eur J Med Genet 2011; 54:e510-5. [PMID: 21684358 DOI: 10.1016/j.ejmg.2011.05.006] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2010] [Accepted: 05/25/2011] [Indexed: 11/24/2022]
Abstract
We report on a family with syndromic X-linked mental retardation (XLMR) caused by an Xp22.2-22.13 duplication. This family consists of a carrier mother and daughter and four affected sons, presenting with mental retardation, developmental delay, cardiovascular problems and mild dysmorphic facial features. Female carriers have normal intelligence and some common clinical features, as well as different clinical abnormalities. Cytogenetic analysis of the mother showed an Xp22.2 duplication which was passed to all her offspring. Fluorescence In Situ Hybridization (FISH) using whole chromosome paint and Bacterial Artificial Chromosome (BAC) clones covering Xp22.12-Xp22.3 region, confirmed the X chromosome origin and the size of the duplication. Two different targeted microarray methodologies were used for breakpoint confirmation, resulting in the localization of the duplication to approximately 9.75-18.98 Mb. Detailed description of such rare duplications provides valuable data for the investigation of genetic disease etiology.
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Ekşioğlu YZ, Pong AW, Takeoka M. A novel mutation in the aristaless domain of the ARX gene leads to Ohtahara syndrome, global developmental delay, and ambiguous genitalia in males and neuropsychiatric disorders in females. Epilepsia 2011; 52:984-92. [DOI: 10.1111/j.1528-1167.2011.02980.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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Gijsbers ACJ, den Hollander NS, Helderman-van de Enden ATJM, Schuurs-Hoeijmakers JHM, Vijfhuizen L, Bijlsma EK, van Haeringen A, Hansson KBM, Bakker E, Breuning MH, Ruivenkamp CAL. X-chromosome duplications in males with mental retardation: pathogenic or benign variants? Clin Genet 2011; 79:71-8. [PMID: 20486941 DOI: 10.1111/j.1399-0004.2010.01438.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Studies to identify copy number variants (CNVs) on the X-chromosome have revealed novel genes important in the causation of X-linked mental retardation (XLMR). Still, for many CNVs it is unclear whether they are associated with disease or are benign variants. We describe six different CNVs on the X-chromosome in five male patients with mental retardation that were identified by conventional karyotyping and single nucleotide polymorphism array analysis. One deletion and five duplications ranging in size from 325 kb to 12.5 Mb were observed. Five CNVs were maternally inherited and one occurred de novo. We discuss the involvement of potential candidate genes and focus on the complexity of X-chromosomal duplications in males inherited from healthy mothers with different X-inactivation patterns. Based on size and/or the presence of XLMR genes we were able to classify CNVs as pathogenic in two patients. However, it remains difficult to decide if the CNVs in the other three patients are pathogenic or benign.
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Affiliation(s)
- A C J Gijsbers
- Center for Human and Clinical Genetics, Leiden University Medical Center (LUMC), Einthovenweg 20, Leiden, The Netherlands.
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Abstract
Autosomal recessive mental retardation (AR-MR) may account for up to 25% of genetic mental retardation (MR). So far, mapping of AR-MR genes in consanguineous families has resulted in six nonsyndromic genes, whereas more than 2000 genes might contribute to AR-MR. We propose to use outbred families with multiple affected siblings for AR-MR gene identification. Homozygosity mapping in ten outbred families with affected brother-sister pairs using a 250 K single nucleotide polymorphism array revealed on average 57 homozygous regions over 1 Mb in size per affected individual (range 20-74). Of these, 21 homozygous regions were shared between siblings on average (range 8-36). None of the shared regions of homozygosity (SROHs) overlapped with the nonsyndromic genes. A total of 13 SROHs had an overlap with previously reported loci for AR-MR, namely with MRT8, MRT9, MRT10 and MRT11. Among these was the longest observed SROH of 11.0 Mb in family ARMR1 on chromosome 19q13, which had 2.9 Mb (98 genes) in common with the 5.4 Mb MRT11 locus (195 genes). These data support that homozygosity mapping in outbred families may contribute to identification of novel AR-MR genes.
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Cossée M, Faivre L, Philippe C, Hichri H, de Saint-Martin A, Laugel V, Bahi-Buisson N, Lemaitre JF, Leheup B, Delobel B, Demeer B, Poirier K, Biancalana V, Pinoit JM, Julia S, Chelly J, Devys D, Mandel JL. ARX polyalanine expansions are highly implicated in familial cases of mental retardation with infantile epilepsy and/or hand dystonia. Am J Med Genet A 2010; 155A:98-105. [DOI: 10.1002/ajmg.a.33785] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
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Abstract
Intellectual disability (ID) is the leading socio-economic problem of health care, but compared to autism and schizophrenia, it has received very little public attention. Important risk factors for ID are malnutrition, cultural deprivation, poor health care, and parental consanguinity. In the Western world, fetal alcohol exposure is the most common preventable cause. Most severe forms of ID have genetic causes. Cytogenetically detectable and submicroscopic chromosomal rearrangements account for approximately 25% of all cases. X-linked gene defects are responsible in 10-12% of males with ID; to date, 91 of these defects have been identified. In contrast, autosomal gene defects have been largely disregarded, but due to coordinated efforts and the advent of next-generation DNA sequencing, this is about to change. As shown for Fra(X) syndrome, this renewed focus on autosomal gene defects will pave the way for molecular diagnosis and prevention, shed more light on the pathogenesis of ID, and reveal new opportunities for therapy.
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Kaufman L, Ayub M, Vincent JB. The genetic basis of non-syndromic intellectual disability: a review. J Neurodev Disord 2010; 2:182-209. [PMID: 21124998 PMCID: PMC2974911 DOI: 10.1007/s11689-010-9055-2] [Citation(s) in RCA: 172] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/09/2010] [Accepted: 06/25/2010] [Indexed: 11/06/2022] Open
Abstract
Intellectual disability (ID), also referred to as mental retardation (MR), is frequently the result of genetic mutation. Where ID is present together with additional clinical symptoms or physical anomalies, there is often sufficient information available for the diagnosing physician to identify a known syndrome, which may then educe the identification of the causative defect. However, where co-morbid features are absent, narrowing down a specific gene can only be done by ‘brute force’ using the latest molecular genetic techniques. Here we attempt to provide a systematic review of genetic causes of cases of ID where no other symptoms or co-morbid features are present, or non-syndromic ID. We attempt to summarize commonalities between the genes and the molecular pathways of their encoded proteins. Since ID is a common feature of autism, and conversely autistic features are frequently present in individuals with ID, we also look at possible overlaps in genetic etiology with non-syndromic ID.
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Lugtenberg D, Zangrande-Vieira L, Kirchhoff M, Whibley AC, Oudakker AR, Kjaergaard S, Vianna-Morgante AM, Kleefstra T, Ruiter M, Jehee FS, Ullmann R, Schwartz CE, Stratton M, Raymond FL, Veltman JA, Vrijenhoek T, Pfundt R, Schuurs-Hoeijmakers JHM, Hehir-Kwa JY, Froyen G, Chelly J, Ropers HH, Moraine C, Gècz J, Knijnenburg J, Kant SG, Hamel BCJ, Rosenberg C, van Bokhoven H, de Brouwer APM. Recurrent deletion of ZNF630 at Xp11.23 is not associated with mental retardation. Am J Med Genet A 2010; 152A:638-45. [PMID: 20186789 DOI: 10.1002/ajmg.a.33292] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
ZNF630 is a member of the primate-specific Xp11 zinc finger gene cluster that consists of six closely related genes, of which ZNF41, ZNF81, and ZNF674 have been shown to be involved in mental retardation. This suggests that mutations of ZNF630 might influence cognitive function. Here, we detected 12 ZNF630 deletions in a total of 1,562 male patients with mental retardation from Brazil, USA, Australia, and Europe. The breakpoints were analyzed in 10 families, and in all cases they were located within two segmental duplications that share more than 99% sequence identity, indicating that the deletions resulted from non-allelic homologous recombination. In 2,121 healthy male controls, 10 ZNF630 deletions were identified. In total, there was a 1.6-fold higher frequency of this deletion in males with mental retardation as compared to controls, but this increase was not statistically significant (P-value = 0.174). Conversely, a 1.9-fold lower frequency of ZNF630 duplications was observed in patients, which was not significant either (P-value = 0.163). These data do not show that ZNF630 deletions or duplications are associated with mental retardation.
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Affiliation(s)
- Dorien Lugtenberg
- Department of Human Genetics, Nijmegen Centre for Molecular Life Sciences and Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
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Abstract
Clinical and Molecular Data on Mental Retardation in BulgariaMental retardation (MR) is clinically and genetically highly heterogeneous. We have done molecular genetic testing on 85 Bulgarian MR patients who were clinically classed as fragile X syndrome (FXS) (n = 32), Rett syndrome (RTT) (n = 36) and Prader-Willi/Angelman syndromes (PWS/AS) (n = 17). We tested for the fragile X MR 1 (FMR1), methyl-CpG binding protein 2 (MECP2), cyclin dependent kinase-like 5 (CDKL5), and Aristaless X (ARX) genes, and did methylation analyses of exon 1 of the small nuclear ribonucleoprotein polypeptide N (SNRPN), and multiplex ligation-dependent probe amplification (MLPA) analyses for large deletions/duplications, and for the methylation status of FMR1 and SNRPN genes. In the FXS group we only found four mutations in the FMR1 gene (12.5%). In the RTT group we found nine mutations in the MECP2 gene (25.0%) but no CDKL5 gene mutations. In the PWS/AS group we found nine mutations in the 15q11-q13 region (53%). Thus, we clarified the molecular basis in 26.0% of the patients. The proportion of genetically proved diagnoses in our RTT patients (25.0%) is relatively high and all these cases are due to MECP2 mutations. Despite the type of mutation, all these cases are very similar from the clinical point of view and well recognized in Bulgaria.
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Zanni G, van Esch H, Bensalem A, Saillour Y, Poirier K, Castelnau L, Ropers HH, de Brouwer APM, Laumonnier F, Fryns JP, Chelly J. A novel mutation in the DLG3 gene encoding the synapse-associated protein 102 (SAP102) causes non-syndromic mental retardation. Neurogenetics 2009; 11:251-5. [PMID: 19795139 DOI: 10.1007/s10048-009-0224-y] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2009] [Accepted: 09/11/2009] [Indexed: 10/20/2022]
Abstract
We have identified a novel splice site mutation (IVS6-1G > A) in the disc-large homolog 3 (DLG3) gene, encoding the synapse-associated protein 102 (SAP102) in one out of 300 families with moderate to severe non-syndromic mental retardation. SAP102 is a member of the neuronal membrane-associated guanylate kinase protein subfamily comprising SAP97, postsynaptic density (PSD)95, and PSD93, which interacts with methyl-D-aspartate receptor and associated protein complexes at the postsynaptic density of excitatory synapses. DLG3 is the first mental retardation gene directly linked to glutamate receptor signalling and trafficking, increasingly recognised as a central mechanism in the regulation of synaptic formation and plasticity in brain and cognitive development.
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Affiliation(s)
- Ginevra Zanni
- Institut Cochin, Université Paris Descartes, INSERM, CNRS UMR 8104, CHU Cochin, Paris, France.
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Bashiardes S, Kousoulidou L, van Bokhoven H, Ropers HH, Chelly J, Moraine C, de Brouwer APM, Van Esch H, Froyen G, Patsalis PC. A new chromosome x exon-specific microarray platform for screening of patients with X-linked disorders. J Mol Diagn 2009; 11:562-8. [PMID: 19779134 DOI: 10.2353/jmoldx.2009.090086] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Recent studies and advances in high-density oligonucleotide arrays have shown that microdeletions and microduplications occur at a high frequency in the human genome, causing various genetic conditions including mental retardation. Thus far little is known about the pathways leading to this disease, and implementation of microarrays is hampered by their increasing cost and complexity, underlining the need for new diagnostic tools. The aim of this study was to introduce a new targeted platform called "chromosome X exon-specific array" and to apply this new platform to screening of 20 families (including one blind positive control) with suspected X-linked mental retardation, to identify new causative X-linked mental retardation genes. The new microarray contains of 21,939 oligonucleotides covering 92.9% of all exons of all genes on chromosome X. Patient screening resulted in successful identification of the blind positive control included in the sample of 20 families, and one of the remaining 19 families was found to carry a 1.78-kilobase deletion involving all exons of pseudogene BRAF2. The BRAF2 deletion segregated in the family and was not found in 200 normal male samples, and no copy number variations are reported in this region. Further studies and focused investigation of X-linked disorders have the potential to reveal the molecular basis of human genetic pathological conditions that are caused by copy-number changes in chromosome X genes.
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Affiliation(s)
- Stavros Bashiardes
- Cyprus Institute of Neurology and Genetics, PO Box 23462, 1683 Nicosia, Cyprus
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Durmaz B, Alpman A, Pariltay E, Akgul M, Ataman E, Kirbiyik O, Cogulu O, Ozkinay F. The evaluation of the referral reasons of patients at a tertiary pediatric genetic center in Izmir, Turkey. Genet Test Mol Biomarkers 2009; 13:163-6. [PMID: 19371213 DOI: 10.1089/gtmb.2008.0074] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Our study aimed to review and evaluate the referral reasons of patients at Department of Pediatric Genetics, Ege University, between 1998 and 2006. In total, 2342 patients were referred to the pediatrics outpatient clinic for dysmorphological examination and suspected genetic conditions. The files were evaluated retrospectively, and they were grouped into five categories. The subgroups included mental retardation (MR)-multiple congenital anomalies and isolated anomalies in 1472 (62.85%), syndromes that may be associated with cytogenetic abnormalities in 634 (27.07%), suspected single-gene disorders in 134 (5.72%), suspected microdeletion syndromes in 48 (2.05%), and other genetic conditions comprising complex multifactorial disorders and ambiguous genitalia in 54 (2.31%). These data have provided useful information on the frequency of different groups of genetic diseases, genetic causes of MR, and the feasibility of genetic services. In conclusion, genetic service should be encouraged among physicians and patients in addition to the diagnosis, prognosis, and disease management efforts.
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Affiliation(s)
- Burak Durmaz
- Division of Genetics, Department of Pediatrics, Faculty of Medicine, Ege University, Izmir, Turkey.
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Pouya AR, Abedini SS, Mansoorian N, Behjati F, Nikzat N, Mohseni M, Nieh SE, Abbasi Moheb L, Darvish H, Monajemi GB, Banihashemi S, Kahrizi K, Ropers HH, Najmabadi H. Fragile X syndrome screening of families with consanguineous and non-consanguineous parents in the Iranian population. Eur J Med Genet 2009; 52:170-3. [PMID: 19361583 DOI: 10.1016/j.ejmg.2009.03.014] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2008] [Accepted: 03/27/2009] [Indexed: 11/20/2022]
Abstract
Fragile X syndrome is the most common form of inherited mental retardation (MR). It is caused by the expansion of CGG triplet repeats in the fragile X mental retardation 1 (FMR1) gene. In mentally retarded males, the frequency of fragile X syndrome is approximately 2-3 percent, but little is known about its proportion in mentally retarded patients from countries where parental consanguinity is common. The objective of this study was to estimate the frequency of fragile X syndrome (FXS) in mentally retarded patients from Iran. We examined a total of 508 families with MR that had been referred to the Genetics Research Center (GRC) in Tehran of which 467 families had at least two mentally retarded children. In 384 families, the parents were related and in 124 they were not related of which most of them had putative or established X-linked inheritance pattern. Full FMR1 mutations were found in 32 of the 508 families studied (6.3%), in 19 out of 124 families with apparently unrelated parents (15.3%), and in 13 of the 384 consanguineous families (3.4%). Thus, in Iran, the relative frequency of FXS seems to be high, and in patients with unrelated parents is much higher. We also show that even in families with consanguineous parents, FXS has to be ruled out before assuming that familial MR is due to autosomal recessive gene defects. Molecular studies are in progress to explain the high proportion of FMR1 mutations in mentally retarded offspring of unrelated Iranian parents.
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Affiliation(s)
- Ali Reza Pouya
- Genetics Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran
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Humeau Y, Gambino F, Chelly J, Vitale N. X-linked mental retardation: focus on synaptic function and plasticity. J Neurochem 2009; 109:1-14. [DOI: 10.1111/j.1471-4159.2009.05881.x] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Nawara M, Klapecki J, Borg K, Jurek M, Moreno S, Tryfon J, Bal J, Chelly J, Mazurczak T. Novel mutation of IL1RAPL1 gene in a nonspecific X-linked mental retardation (MRX) family. Am J Med Genet A 2009; 146A:3167-72. [PMID: 19012350 DOI: 10.1002/ajmg.a.32613] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Mental retardation (MR) affects approximately 2% of the population. About 10% of all MR cases result from defects of X-linked genes. Mutations in most of more than 20 known genes causing nonspecific form of X-linked MR (MRX) are very rare and may account for less than 0.5-1% of MR. Linkage studies in extended pedigrees followed by mutational analysis of known MRX genes in the linked interval are often the only way to identify a genetic cause of the disorder. We performed linkage analysis in several MRX families, and in one family with four males with MR we mapped the disease to an interval encompassing Xp21.2-22.11 (with a maximum LOD score of 2.71). Subsequent mutation analysis of genes located in this interval allowed us to identify a partial deletion of the IL1RAPL1 gene. Different nonoverlapping deletions involving IL1RAPL1 have been reported previously, suggesting that this region could be deletion-prone. In this report, we present the results of the molecular analyses and clinical examinations of four affected family members with the deletion in IL1RAPL1. Our data further confirm the importance and usefulness of linkage studies for gene mapping in MRX families and demonstrate that IL1RAPL1 plays an important role in the etiology of MRX. With the development of new methods (aCGH, MLPA), further rearrangements in this gene (including deletions and duplications) might be discovered in the nearest future.
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Affiliation(s)
- Magdalena Nawara
- Department of Medical Genetics, Institute of Mother and Child, Warsaw, Poland.
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Ropers HH. Genetics of intellectual disability. Curr Opin Genet Dev 2008; 18:241-50. [DOI: 10.1016/j.gde.2008.07.008] [Citation(s) in RCA: 143] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2008] [Accepted: 07/15/2008] [Indexed: 11/16/2022]
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Kesler SR, Reiss AL, Vohr B, Watson C, Schneider KC, Katz KH, Maller-Kesselman J, Silbereis J, Constable RT, Makuch RW, Ment LR. Brain volume reductions within multiple cognitive systems in male preterm children at age twelve. J Pediatr 2008; 152:513-20, 520.e1. [PMID: 18346506 PMCID: PMC3270939 DOI: 10.1016/j.jpeds.2007.08.009] [Citation(s) in RCA: 111] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/14/2007] [Revised: 07/10/2007] [Accepted: 08/10/2007] [Indexed: 11/17/2022]
Abstract
OBJECTIVES To more precisely examine regional and subregional microstructural brain changes associated with preterm birth. STUDY DESIGN We obtained brain volumes from 29 preterm children, age 12 years, with no ultrasound scanning evidence of intraventricular hemorrhage or cystic periventricular leukomalacia in the newborn period, and 22 age- and sex-matched term control subjects. RESULTS Preterm male subjects demonstrated significantly lower white matter volumes in bilateral cingulum, corpus callosum, corticospinal tract, prefrontal cortex, superior and inferior longitudinal fasciculi compared with term male subjects. Gray matter volumes in prefrontal cortex, basal ganglia, and temporal lobe also were significantly reduced in preterm male subjects. Brain volumes of preterm female subjects were not significantly different from those of term female control subjects. Voxel-based morphometry results were not correlated with perinatal variables or cognitive outcome. Higher maternal education was associated with higher cognitive performance in preterm male subjects. CONCLUSIONS Preterm male children continue to demonstrate abnormal neurodevelopment at 12 years of age. However, brain morphology in preterm female children may no longer differ from that of term female children. The neurodevelopmental abnormalities we detected in preterm male subjects appear to be relatively diffuse, involving multiple neural systems. The relationship between aberrant neurodevelopment and perinatal variables may be mediated by genetic factors, environmental factors, or both reflected in maternal education level.
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Affiliation(s)
- Shelli R Kesler
- Center for Interdisciplinary Brain Sciences Research, Stanford University School of Medicine, Stanford, CA 94305-5795, USA.
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Abstract
X-linked mental retardation (XLMR) is a common cause of inherited intellectual disability with an estimated prevalence of approximately 1/1000 males. Most XLMR conditions are inherited as X-linked recessive traits, although female carriers may manifest usually milder symptoms. We have listed 215 XLMR conditions, subdivided according to their clinical presentation: 149 with specific clinical findings, including 98 syndromes and 51 neuromuscular conditions, and 66 nonspecific (MRX) forms. We also present a map of the 82 XLMR genes cloned to date (November 2007) and a map of the 97 conditions that have been positioned by linkage analysis or cytogenetic breakpoints. We briefly consider the molecular function of known XLMR proteins and discuss the possible strategies to identify the remaining XLMR genes. Final remarks are made on the natural history of XLMR conditions and on diagnostic issues.
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Affiliation(s)
- Pietro Chiurazzi
- Institute of Medical Genetics, Catholic University, Rome, Italy.
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Nadif Kasri N, Van Aelst L. Rho-linked genes and neurological disorders. Pflugers Arch 2007; 455:787-97. [PMID: 18004590 DOI: 10.1007/s00424-007-0385-1] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2006] [Accepted: 10/29/2007] [Indexed: 12/11/2022]
Abstract
Mental retardation (MR) is a common cause of intellectual disability and affects approximately 2 to 3% of children and young adults. Many forms of MR are associated with abnormalities in dendritic structure and/or dendritic spine morphology. Given that dendritic spine morphology has been tightly linked to synaptic activity, altered spine morphology has been suggested to underlie or contribute to the cognitive disabilities associated with MR. The structure and dynamics of dendritic spines is determined by its underlying actin cytoskeleton. Signaling molecules and cascades important for cytoskeletal regulation have therefore attracted a great deal of attention. As key regulators of both the actin and microtubule cytoskeletons, it is not surprising that the Rho GTPases have emerged as important regulators of dendrite and spine structural plasticity. Significantly, mutations in regulators and effectors of Rho GTPases have been associated with diseases affecting the nervous system, including MR and amyotrophic lateral sclerosis (ALS). Here, we will discuss Rho GTPase-related genes and their signaling pathways involved in MR and ALS.
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Affiliation(s)
- Nael Nadif Kasri
- Cold Spring Harbor Laboratory, 1 Bungtown Road, Demerec Building, Cold Spring Harbor, NY 11724, USA.
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Koivisto AM, Ala-Mello S, Lemmelä S, Komu HA, Rautio J, Järvelä I. Screening of mutations in the PHF8 gene and identification of a novel mutation in a Finnish family with XLMR and cleft lip/cleft palate. Clin Genet 2007; 72:145-9. [PMID: 17661819 DOI: 10.1111/j.1399-0004.2007.00836.x] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We investigated the prevalence of mutations in the PHD finger protein 8 (PHF8) gene in X-linked mental retardation (XLMR) and facial cleft starting from the original cohort of 7712 patients operated on since 1 January 1950 for cleft lip/cleft palate in the Cleft Centre at the Helsinki University Hospital. From this nationwide material, 18 patients including one family with two male patients with cleft lip/cleft palate and unknown cause of mental retardation (MR) were sequenced for the coding regions and splice sites of the PHF8 gene. A novel missense mutation c.836C>T of the PHF8 gene was identified in a Finnish family with multiple-affected male patients. The mutation resides in exon 8 and changes phenylalanine to serine (F279S) in the functionally important Jmonji C domain of the protein. The clinical phenotype of the male patients was characterized by mild MR, mild dysmorphic features, unilateral cleft lip and cleft palate in one and bilateral cleft lip and cleft palate in the other sibling. The mutation was not present in 200 anonymous blood donors (approximately 300 X-chromosomes). To our knowledge, F279S is the third mutation of the PHF8 gene identified so far.
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Affiliation(s)
- A M Koivisto
- Department of Medical Genetics, University of Helsinki, Helsinki, Finland
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Froyen G, Van Esch H, Bauters M, Hollanders K, Frints SGM, Vermeesch JR, Devriendt K, Fryns JP, Marynen P. Detection of genomic copy number changes in patients with idiopathic mental retardation by high-resolution X-array-CGH: important role for increased gene dosage of XLMR genes. Hum Mutat 2007; 28:1034-42. [PMID: 17546640 DOI: 10.1002/humu.20564] [Citation(s) in RCA: 146] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
A tiling X-chromosome-specific genomic array with a theoretical resolution of 80 kb was developed to screen patients with idiopathic mental retardation (MR) for submicroscopic copy number differences. Four patients with aberrations previously detected at lower resolution were first analyzed. This facilitated delineation of the location and extent of the aberration at high resolution and subsequently, more precise genotype-phenotype analyses. A cohort of 108 patients was screened, 57 of which were suspected of X-linked mental retardation (XLMR), 26 were probands of brother pairs, and 25 were sporadic cases. A total of 15 copy number changes in 14 patients (13%) were detected, which included two deletions and 13 duplications ranging from 0.1 to 2.7 Mb. The aberrations are associated with the phenotype in five patients (4.6%), based on the following criteria: de novo aberration; involvement of a known or candidate X-linked nonsyndromic(syndromic) MR (MRX(S)) gene; segregation with the disease in the family; absence in control individuals; and skewed X-inactivation in carrier females. These include deletions that contain the MRX(S) genes CDKL5, OPHN1, and CASK, and duplications harboring CDKL5, NXF5, MECP2, and GDI1. In addition, seven imbalances were apparent novel polymorphic regions because they do not fulfill the proposed criteria. Taken together, our data strongly suggest that not only deletions but also duplications on the X chromosome contribute to the phenotype more often than expected, supporting the increased gene dosage mechanism for deregulation of normal cognitive development.
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Affiliation(s)
- Guy Froyen
- Human Genome Laboratory, Department for Molecular and Developmental Genetics, VIB, Leuven, Belgium.
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Troester MM, Trachtenberg T, Narayanan V. A novel mutation of the ARX gene in a male with nonsyndromic mental retardation. J Child Neurol 2007; 22:744-8. [PMID: 17641262 DOI: 10.1177/0883073807304000] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
ARX (Aristaless-related homeobox gene) is located at Xp22. It contains 5 exons and encodes a 562-amino acid protein. The protein contains 4 polyalanine tracts, 3 of which are encoded in exon 2 and 1 in exon 4. Mutations in the ARX gene have been found in X-linked infantile spasms syndrome, Partington syndrome (mental retardation with dystonic movements of the hands), X-linked lissencephaly with abnormal genitalia, X-linked myoclonus epilepsy with spasticity and intellectual disability, and in nonsyndromic X-linked mental retardation. The most common mutation in ARX (seen in X-linked infantile spasms syndrome, Partington syndrome, and X-linked mental retardation) is a 24-bp duplication in exon 2 resulting in expansion of a polyalanine tract. Truncating mutations (deletions, frameshift, non-sense) have been found in X-linked lissencephaly with abnormal genitalia, as well as homeodomain missense mutations in X-linked myoclonus epilepsy with spasticity and intellectual disability. The authors report a novel 24-bp in-frame deletion within exon 2 of the ARX gene in a male child with X-linked mental retardation and review the spectrum of ARX mutations. This mutation results in a contraction of the second polyalanine repeat.
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Affiliation(s)
- Matthew M Troester
- Children's Health Center, St. Joseph's Hospital and Medical Center, Barrow Neurological Institute Phoenix, Arizona, USA
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46
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Campos M, Abdalla CB, Santos-Rebouças CB, dos Santos AV, Pestana CP, Domingues ML, dos Santos JM, Pimentel MMG. Low significance of MECP2 mutations as a cause of mental retardation in Brazilian males. Brain Dev 2007; 29:293-7. [PMID: 17084570 DOI: 10.1016/j.braindev.2006.09.012] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/19/2006] [Revised: 08/11/2006] [Accepted: 09/26/2006] [Indexed: 11/24/2022]
Abstract
MeCP2 is a protein that selectively binds to methylated cytosines through its methyl-CpG-binding domain (MBD) and connects DNA methylation to transcriptional repression. Mutations in MECP2 gene, located in Xq28, have been reported as being the major cause of Rett syndrome and are also associated with some cases of X-linked mental retardation in both males and females. In this study, we present the first screening in the MECP2 gene in a Brazilian cohort of 239 unrelated males with idiopathic mental retardation. Eight sequence variations were observed in 10 patients: one novel putative pathogenic variant, two never described variants of unknown pathogenic value and five non-pathogenic variations. We conclude that in mentally retarded Brazilian males, non-pathogenic variants in the MECP2 gene are more common than actual pathogenic mutations, and therefore alterations in this gene have a weak relationship with mental retardation in males.
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Affiliation(s)
- Mário Campos
- Human Genetics Service, Department of Cell Biology and Genetics, State University of Rio de Janeiro, Rua São Francisco Xavier 524, Maracanã, Rio de Janeiro 20550-013, Brazil
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Laperuta C, Spizzichino L, D'Adamo P, Monfregola J, Maiorino A, D'Eustacchio A, Ventruto V, Neri G, D'Urso M, Chiurazzi P, Ursini MV, Miano MG. MRX87 family with Aristaless X dup24bp mutation and implication for polyAlanine expansions. BMC MEDICAL GENETICS 2007; 8:25. [PMID: 17480217 PMCID: PMC1868705 DOI: 10.1186/1471-2350-8-25] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/22/2006] [Accepted: 05/04/2007] [Indexed: 12/02/2022]
Abstract
Background Cognitive impairments are heterogeneous conditions, and it is estimated that 10% may be caused by a defect of mental function genes on the X chromosome. One of those genes is Aristaless related homeobox (ARX) encoding a polyA-rich homeobox transcription factor essential for cerebral patterning and its mutations cause different neurologic disorders. We reported on the clinical and genetic analysis of an Italian family with X-linked mental retardation (XLMR) and intra-familial heterogeneity, and provided insight into its molecular defect. Methods We carried out on linkage-candidate gene studies in a new MRX family (MRX87). All coding regions and exon-intron boundaries of ARX gene were analysed by direct sequencing. Results MRX87 patients had moderate to profound cognition impairment and a combination of minor congenital anomalies. The disease locus, MRX87, was mapped between DXS7104 and DXS1214, placing it in Xp22-p21 interval, a hot spot region for mental handicap. An in frame duplication of 24 bp (ARXdup24) in the second polyAlanine tract (polyA_II) in ARX was identified. Conclusion Our study underlines the role of ARXdup24 as a critical mutational site causing mental retardation linked to Xp22. Phenotypic heterogeneity of MRX87 patients represents a new observation relevant to the functional consequences of polyAlanine expansions enriching the puzzling complexity of ARXdup24-linked diseases.
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Affiliation(s)
- Carmela Laperuta
- Institute of Genetics and Biophysics "Adriano Buzzati Traverso" CNR, Naples, Italy
| | | | - Pio D'Adamo
- Telethon Institute of Genetics and Medicine, TIGEM, Naples, Italy
| | - Jlenia Monfregola
- Institute of Genetics and Biophysics "Adriano Buzzati Traverso" CNR, Naples, Italy
| | | | | | - Valerio Ventruto
- Institute of Genetics and Biophysics "Adriano Buzzati Traverso" CNR, Naples, Italy
| | | | - Michele D'Urso
- Institute of Genetics and Biophysics "Adriano Buzzati Traverso" CNR, Naples, Italy
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Bottani A, Chelly J, de Brouwer APM, Pardo B, Barker M, Capra V, Bartoloni L, Antonarakis SE, Conrad B. Sequence variation in ultraconserved and highly conserved elements does not cause X-linked mental retardation. Am J Med Genet A 2007; 143A:888-90. [PMID: 17352392 DOI: 10.1002/ajmg.a.31651] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Armand Bottani
- Department of Genetic Medicine and Development, Geneva University Medical School and University Hospitals, Geneva, Switzerland
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Chen W, Jensen LR, Gecz J, Fryns JP, Moraine C, de Brouwer A, Chelly J, Moser B, Ropers HH, Kuss AW. Mutation screening of brain-expressed X-chromosomal miRNA genes in 464 patients with nonsyndromic X-linked mental retardation. Eur J Hum Genet 2006; 15:375-8. [PMID: 17180121 DOI: 10.1038/sj.ejhg.5201758] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
MiRNAs are small noncoding RNAs that control the expression of target genes at the post-transcriptional level and have been reported to modulate various biological processes. Their function as regulatory factors in gene expression renders them attractive candidates for harbouring genetic variants with subtle effects on IQ. In an attempt to investigate the potential role of miRNAs in the aetiology of X-linked mental retardation, we have examined all 13 known, brain-expressed X-chromosomal miRNAs in a cohort of 464 patients with non-syndromic X-linked MR and found four nucleotide changes in three different pre-miRNA hairpins. All the observed changes appear to be functionally neutral which, taken together with the rarity of detected nucleotide changes in miRNA genes, may reflect strong selection and thus underline the functional importance of miRNAs.
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Affiliation(s)
- Wei Chen
- Max Planck Institute for Molecular Genetics, Berlin, Germany
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Rauch A, Hoyer J, Guth S, Zweier C, Kraus C, Becker C, Zenker M, Hüffmeier U, Thiel C, Rüschendorf F, Nürnberg P, Reis A, Trautmann U. Diagnostic yield of various genetic approaches in patients with unexplained developmental delay or mental retardation. Am J Med Genet A 2006; 140:2063-74. [PMID: 16917849 DOI: 10.1002/ajmg.a.31416] [Citation(s) in RCA: 255] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/08/2022]
Abstract
The underlying cause of mental retardation remains unknown in up to 80% of patients. As chromosomal aberrations are the most common known cause of mental retardation, several new methods based on FISH, PCR, and array techniques have been developed over recent years to increase detection rate of subtle aneusomies initially of the gene rich subtelomeric regions, but nowadays also genome wide. As the reported detection rates vary widely between different reports and in order to compare the diagnostic yield of various investigations, we analyzed the diagnostic yield of conventional karyotyping, subtelomeric screening, molecular karyotyping, X-inactivation studies, and dysmorphological evaluation with targeted laboratory testing in unselected patients referred for developmental delay or mental retardation to our cytogenetic laboratory (n = 600) and to our genetic clinic (n = 570). In the cytogenetic group, 15% of patients showed a disease-related aberration, while various targeted analyses after dysmorphological investigation led to a diagnosis in about 20% in the genetic clinic group. When adding the patients with a cytogenetic aberration to the patient group seen in genetic clinic, an etiological diagnosis was established in about 40% of the combined study group. A conventional cytogenetic diagnosis was present in 16% of combined patients and a microdeletion syndrome was diagnosed in 5.3%, while subtelomeric screening revealed only 1.3% of causes. Molecular karyotyping with a 10 K SNP array in addition revealed 5% of underlying causes, but 29% of all diagnoses would have been detectable by molecular karyotyping. In those patients without a clear diagnosis, 5.6% of mothers of affected boys showed significant (>95%) skewing of X-inactivation suggesting X-linked mental retardation. The most common diagnoses with a frequency of more than 0.5% were Down syndrome (9.2%), common microdeletion 22q11.2 (2.4%), Williams-Beuren syndrome (1.3%), Fragile-X syndrome (1.2%), Cohen syndrome (0.7%), and monosomy 1p36.3 (0.6%). From our data, we suggest the following diagnostic procedure in patients with unexplained developmental delay or mental retardation: (1) Clinical/dysmorphological investigation with respective targeted analyses; (2) In the remaining patients without an etiological diagnosis, we suggest conventional karyotyping, X-inactivation screening in mothers of boys, and molecular karyotyping, if available. If molecular karyotyping is not available, subtelomeric screening should be performed.
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Affiliation(s)
- Anita Rauch
- Institute of Human Genetics, Friedrich-Alexander University Erlangen-Nuremberg, Erlangen, Germany.
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