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Hu M, Bodnar B, Zhang Y, Xie F, Li F, Li S, Zhao J, Zhao R, Gedupoori N, Mo Y, Lin L, Li X, Meng W, Yang X, Wang H, Barbe MF, Srinivasan S, Bethea JR, Mo X, Xu H, Hu W. Defective neurite elongation and branching in Nibp/Trappc9 deficient zebrafish and mice. Int J Biol Sci 2023; 19:3226-3248. [PMID: 37416774 PMCID: PMC10321293 DOI: 10.7150/ijbs.78489] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Accepted: 06/06/2023] [Indexed: 07/08/2023] Open
Abstract
Loss of function in transport protein particles (TRAPP) links a new set of emerging genetic disorders called "TRAPPopathies". One such disorder is NIBP syndrome, characterized by microcephaly and intellectual disability, and caused by mutations of NIBP/TRAPPC9, a crucial and unique member of TRAPPII. To investigate the neural cellular/molecular mechanisms underlying microcephaly, we developed Nibp/Trappc9-deficient animal models using different techniques, including morpholino knockdown and CRISPR/Cas mutation in zebrafish and Cre/LoxP-mediated gene targeting in mice. Nibp/Trappc9 deficiency impaired the stability of the TRAPPII complex at actin filaments and microtubules of neurites and growth cones. This deficiency also impaired elongation and branching of neuronal dendrites and axons, without significant effects on neurite initiation or neural cell number/types in embryonic and adult brains. The positive correlation of TRAPPII stability and neurite elongation/branching suggests a potential role for TRAPPII in regulating neurite morphology. These results provide novel genetic/molecular evidence to define patients with a type of non-syndromic autosomal recessive intellectual disability and highlight the importance of developing therapeutic approaches targeting the TRAPPII complex to cure TRAPPopathies.
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Affiliation(s)
- Min Hu
- Laboratory of Stem Cell Biology, State Key Laboratory of Biotherapy, West China Hospital, West China Medical School, Sichuan University, Chengdu 610041, China
| | - Brittany Bodnar
- Center for Metabolic Disease Research, Department of Pathalogy and Laboratory Medicine, Temple University Lewis Katz School of Medicine, Philadelphia, PA, USA
| | - Yonggang Zhang
- Center for Stem Cell Research and Application, Institute of Blood Transfusion, Chinese Academy of Medical Sciences & Peking Union Medical College (CAMS & PUMC), Chengdu 610052, China
| | - Fangxin Xie
- Center for Stem Cell Research and Application, Institute of Blood Transfusion, Chinese Academy of Medical Sciences & Peking Union Medical College (CAMS & PUMC), Chengdu 610052, China
- Department of Clinical Laboratory, Xi'an NO. 3 Hospital, Xi'an, Shaanxi, 710018, China
| | - Fang Li
- Center for Metabolic Disease Research, Department of Pathalogy and Laboratory Medicine, Temple University Lewis Katz School of Medicine, Philadelphia, PA, USA
| | - Siying Li
- Laboratory of Stem Cell Biology, State Key Laboratory of Biotherapy, West China Hospital, West China Medical School, Sichuan University, Chengdu 610041, China
| | - Jin Zhao
- Laboratory of Stem Cell Biology, State Key Laboratory of Biotherapy, West China Hospital, West China Medical School, Sichuan University, Chengdu 610041, China
| | - Ruotong Zhao
- Center for Metabolic Disease Research, Department of Pathalogy and Laboratory Medicine, Temple University Lewis Katz School of Medicine, Philadelphia, PA, USA
| | - Naveen Gedupoori
- Center for Metabolic Disease Research, Department of Pathalogy and Laboratory Medicine, Temple University Lewis Katz School of Medicine, Philadelphia, PA, USA
| | - Yifan Mo
- Center for Metabolic Disease Research, Department of Pathalogy and Laboratory Medicine, Temple University Lewis Katz School of Medicine, Philadelphia, PA, USA
| | - Lanyi Lin
- Center for Metabolic Disease Research, Department of Pathalogy and Laboratory Medicine, Temple University Lewis Katz School of Medicine, Philadelphia, PA, USA
| | - Xue Li
- Laboratory of Stem Cell Biology, State Key Laboratory of Biotherapy, West China Hospital, West China Medical School, Sichuan University, Chengdu 610041, China
| | - Wentong Meng
- Laboratory of Stem Cell Biology, State Key Laboratory of Biotherapy, West China Hospital, West China Medical School, Sichuan University, Chengdu 610041, China
| | - Xiaofeng Yang
- Center for Metabolic Disease Research, Department of Pathalogy and Laboratory Medicine, Temple University Lewis Katz School of Medicine, Philadelphia, PA, USA
| | - Hong Wang
- Center for Metabolic Disease Research, Department of Pathalogy and Laboratory Medicine, Temple University Lewis Katz School of Medicine, Philadelphia, PA, USA
| | - Mary F. Barbe
- Center for Metabolic Disease Research, Department of Pathalogy and Laboratory Medicine, Temple University Lewis Katz School of Medicine, Philadelphia, PA, USA
| | - Shanthi Srinivasan
- Division of Digestive Diseases, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia, USA
| | - John R. Bethea
- Department of Biology, Drexel University, Philadelphia, PA, USA
| | - Xianming Mo
- Laboratory of Stem Cell Biology, State Key Laboratory of Biotherapy, West China Hospital, West China Medical School, Sichuan University, Chengdu 610041, China
| | - Hong Xu
- Laboratory of Stem Cell Biology, State Key Laboratory of Biotherapy, West China Hospital, West China Medical School, Sichuan University, Chengdu 610041, China
| | - Wenhui Hu
- Laboratory of Stem Cell Biology, State Key Laboratory of Biotherapy, West China Hospital, West China Medical School, Sichuan University, Chengdu 610041, China
- Center for Metabolic Disease Research, Department of Pathalogy and Laboratory Medicine, Temple University Lewis Katz School of Medicine, Philadelphia, PA, USA
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Jauss RT, Schließke S, Abou Jamra R. Routine Diagnostics Confirm Novel Neurodevelopmental Disorders. Genes (Basel) 2022; 13:2305. [PMID: 36553572 PMCID: PMC9778535 DOI: 10.3390/genes13122305] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Revised: 12/05/2022] [Accepted: 12/06/2022] [Indexed: 12/13/2022] Open
Abstract
Routine diagnostics is biased towards genes and variants with satisfactory evidence, but rare disorders with only little confirmation of their pathogenicity might be missed. Many of these genes can, however, be considered relevant, although they may have less evidence because they lack OMIM entries or comprise only a small number of publicly available variants from one or a few studies. Here, we present 89 individuals harbouring variants in 77 genes for which only a small amount of public evidence on their clinical significance is available but which we still found to be relevant enough to be reported in routine diagnostics. For 21 genes, we present case reports that confirm the lack or provisionality of OMIM associations (ATP6V0A1, CNTN2, GABRD, NCKAP1, RHEB, TCF7L2), broaden the phenotypic spectrum (CC2D1A, KCTD17, YAP1) or substantially strengthen the confirmation of genes with limited evidence in the medical literature (ADARB1, AP2M1, BCKDK, BCORL1, CARS2, FBXO38, GABRB1, KAT8, PRKD1, RAB11B, RUSC2, ZNF142). Routine diagnostics can provide valuable information on disease associations and support for genes without requiring tremendous research efforts. Thus, our results validate and delineate gene-disorder associations with the aim of motivating clinicians and scientists in diagnostic departments to provide additional evidence via publicly available databases or by publishing short case reports.
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Affiliation(s)
- Robin-Tobias Jauss
- Institute of Human Genetics, University of Leipzig Medical Center, Philipp-Rosenthal-Straße 55, 04103 Leipzig, Germany
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Davarniya B, Hu H, Kahrizi K, Musante L, Fattahi Z, Hosseini M, Maqsoud F, Farajollahi R, Wienker TF, Ropers HH, Najmabadi H. The Role of a Novel TRMT1 Gene Mutation and Rare GRM1 Gene Defect in Intellectual Disability in Two Azeri Families. PLoS One 2015; 10:e0129631. [PMID: 26308914 PMCID: PMC4550366 DOI: 10.1371/journal.pone.0129631] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2014] [Accepted: 05/11/2015] [Indexed: 12/21/2022] Open
Abstract
Cognitive impairment or intellectual disability (ID) is a widespread neurodevelopmental disorder characterized by low IQ (below 70). ID is genetically heterogeneous and is estimated to affect 1-3% of the world's population. In affected children from consanguineous families, autosomal recessive inheritance is common, and identifying the underlying genetic cause is an important issue in clinical genetics. In the framework of a larger project, aimed at identifying candidate genes for autosomal recessive intellectual disorder (ARID), we recently carried out single nucleotide polymorphism-based genome-wide linkage analysis in several families from Ardabil province in Iran. The identification of homozygosity-by-descent loci in these families, in combination with whole exome sequencing, led us to identify possible causative homozygous changes in two families. In the first family, a missense variant was found in GRM1 gene, while in the second family, a frameshift alteration was identified in TRMT1, both of which were found to co-segregate with the disease. GRM1, a known causal gene for autosomal recessive spinocerebellar ataxia (SCAR13, MIM#614831), encodes the metabotropic glutamate receptor1 (mGluR1). This gene plays an important role in synaptic plasticity and cerebellar development. Conversely, the TRMT1 gene encodes a tRNA methyltransferase that dimethylates a single guanine residue at position 26 of most tRNAs using S-adenosyl methionine as the methyl group donor. We recently presented TRMT1 as a candidate gene for ARID in a consanguineous Iranian family (Najmabadi et al., 2011). We believe that this second Iranian family with a biallelic loss-of-function mutation in TRMT1 gene supports the idea that this gene likely has function in development of the disorder.
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Affiliation(s)
- Behzad Davarniya
- Genetics Research Center (GRC), University of Social Welfare and Rehabilitation Sciences, Tehran, Iran
| | - Hao Hu
- Department of Human Molecular Genetics, Max-Plank Institute for Molecular Genetics, Berlin, Germany
| | - Kimia Kahrizi
- Genetics Research Center (GRC), University of Social Welfare and Rehabilitation Sciences, Tehran, Iran
| | - Luciana Musante
- Department of Human Molecular Genetics, Max-Plank Institute for Molecular Genetics, Berlin, Germany
| | - Zohreh Fattahi
- Genetics Research Center (GRC), University of Social Welfare and Rehabilitation Sciences, Tehran, Iran
| | - Masoumeh Hosseini
- Genetics Research Center (GRC), University of Social Welfare and Rehabilitation Sciences, Tehran, Iran
| | | | | | - Thomas F. Wienker
- Department of Human Molecular Genetics, Max-Plank Institute for Molecular Genetics, Berlin, Germany
| | - H. Hilger Ropers
- Department of Human Molecular Genetics, Max-Plank Institute for Molecular Genetics, Berlin, Germany
| | - Hossein Najmabadi
- Genetics Research Center (GRC), University of Social Welfare and Rehabilitation Sciences, Tehran, Iran
- * E-mail:
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Soltani Banavandi MJ, Kahrizi K, Behjati F, Mohseni M, Darvish H, Bahman I, Abedinni SS, Ghasemi Firouzabadi S, Jafari E, Ghadami S, Sabbagh F, Kavoosi GR, Najmabadi H. Investigation of genetic causes of intellectual disability in kerman province, South East of iran. IRANIAN RED CRESCENT MEDICAL JOURNAL 2012; 14:79-85. [PMID: 22737560 PMCID: PMC3372047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/10/2011] [Accepted: 10/12/2011] [Indexed: 11/30/2022]
Abstract
BACKGROUND Intellectual disability (ID) has a worldwide prevalence of 1-3% and results from extraordinary heterogeneous. To shed more light on the causes of ID in Kerman Province, in Southeast Iran, we set out in 2008 to perform systematic clinical studies and homozygosity mapping in large Iranian families with ID. METHODS Fifty seven families with a minimum of two mentally retarded children from Kerman Province were initially tested for metabolic disorders, by Tandem mass spectrometry. Fragile X testing and standard karyotyping were performed for all probands of families. Cases with autosomal recessive (AR) pattern of inheritance and microcephaly were subjected to homozygosity mapping by using several microsatellite markers for known MCPH loci. RESULTS Three out of seven families with X-linked pattern of inheritance were positive for fragile X syndrome. Chromosome abnormality was not observed in any of dysmorphic patients and all families were negative for metabolic tests. Among the remaining 50 families of AR ID, six were found to be microcephalic, of which 2 linked to two MCPH loci (33.3%). The rest 4 families were not linked to any of the known loci. CONCLUSION The results of this study showed that ID with microcephaly comprised 12% of ID cases in Kerman Province. In two families with apparent linkage to the MCPH5 and MCPH6 locus, mutation screening was not successful, which might indicate that either the mutation is located in the regulatory sequences of the gene or that there might be another genes present in these regions, which is mutated in such cases.
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Affiliation(s)
- M J Soltani Banavandi
- Faculty of Basic Science, Science and Research Branch, Islamic Azad University, Fars, Iran,Genetics Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran
| | - K Kahrizi
- Genetics Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran
| | - F Behjati
- Genetics Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran
| | - M Mohseni
- Genetics Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran
| | - H Darvish
- Genetics Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran
| | - I Bahman
- Genetics Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran
| | - S S Abedinni
- Genetics Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran
| | - S Ghasemi Firouzabadi
- Genetics Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran
| | - E Jafari
- Deptartment of Microbiology, Faculty of Basic Science, Islamic Azad University, Kerman Branch, Kerman, Iran
| | - Sh Ghadami
- Genetics Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran
| | - F Sabbagh
- Genetics Counseling Center, Welfare Organization of Kerman Province, Kerman, Iran
| | - Gh R Kavoosi
- Institute of Biotechnology, University of Shiraz, Shiraz, Iran
| | - H Najmabadi
- Genetics Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran,Correspondence: Hossein Najmabadi, PhD, Genetics Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran. Tel.: +98-21-22180138, Fax: +98-21-22180138, E-mail:
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Shi ZY, Li YJ, Zhang KJ, Gao XC, Zheng ZJ, Han N, Zhang FC. Positive association of CC2D1A and CC2D2A gene haplotypes with mental retardation in a Han Chinese population. DNA Cell Biol 2011; 31:80-7. [PMID: 22023432 DOI: 10.1089/dna.2011.1253] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The CC2D1A and CC2D2A genes are involved in Ca(2+)-regulated signaling pathways and have recently been implicated in the etiology of mental retardation (MR). The aim of this study was to investigate whether CC2D1A and CC2D2A polymorphisms are associated with susceptibility to MR in a Han Chinese population using a family based association approach. The sample included 172 trios (parents and offspring), and all subjects were genotyped for several single-nucleotide polymorphisms covering CC2D1A and CC2D2A. Linkage disequilibrium (LD) analysis revealed that the rs6511901 and rs10410239 polymorphisms of CC2D1A were in strong LD (D'=0.865), and haplotype analysis showed evidence for over-transmission from parents to MR offspring (p=0.0009). The LD analysis also revealed that CC2D2A single-nucleotide polymorphisms rs10025837, rs13116304, and rs7661102 were in strong LD (D'=0.848), and haplotype analysis showed significant transmission disequilibrium (p=0.0004). The results suggest the involvement of CC2D1A and CC2D2A in MR in the Han Chinese population, and some specific haplotypes may be susceptible or protective.
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Affiliation(s)
- Zhang-Yan Shi
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, Institute of Population and Health, Institute of Application Psychology, Northwest University, 229 Tai Bai Road, Xi'an, China
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6
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Nolan DK, Chen P, Das S, Ober C, Waggoner D. Fine mapping of a locus for nonsyndromic mental retardation on chromosome 19p13. Am J Med Genet A 2008; 146A:1414-22. [PMID: 18446860 DOI: 10.1002/ajmg.a.32307] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Mental retardation (MR) occurs in approximately 3% of the population and therefore significantly impacts public health. Despite this relatively high prevalence, the specific causes of MR remain unknown in most cases, although both genetic and environmental factors are known to contribute. We describe a consanguineous family with autosomal recessive (AR) nonsyndromic MR (NSMR). Because the consanguinity of this family is complex, we explore alternative approaches for generating accurate estimates of the evidence for linkage in this family, and demonstrate evidence for linkage to chromosome 19p13 (lod score ranging from 1.2 to 3.5, depending on assumptions of allele frequencies). Fine mapping of the linked region defined a critical region of 3.6 Mb, which overlaps with a previously reported gene (CC2D1A) for MR. However, no mutations in the coding region of this gene are present in the family we describe. These results suggest that another gene causing autosomal recessive nonsyndromic MR (ARNSMR) is located within this genomic region.
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Affiliation(s)
- D K Nolan
- Committee on Genetics, University of Chicago, Chicago, Illinois 60637, USA
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Rogaeva A, Galaraga K, Albert PR. The Freud-1/CC2D1A family: transcriptional regulators implicated in mental retardation. J Neurosci Res 2008; 85:2833-8. [PMID: 17394259 DOI: 10.1002/jnr.21277] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The CC2D1A gene family consists of two homologous genes, Freud-1/CC2D1A and Freud-2/CC2D1B, that share conserved domains, including several DM14 domains that are specific to this protein family, a C-terminal helix-loop-helix domain, and a C2 calcium-dependent phospholipid binding domain. Although the function of Freud-2 is unknown, Freud-1 has been shown to function as a transcriptional repressor of the serotonin-1A receptor gene that binds to a novel DNA element (FRE, 5'-repressor element). The DNA binding and repressor activities of Freud-1 are inhibited by calcium-calmodulin-dependent protein kinase. Recently, a deletion in the CC2D1A gene has been linked to nonsyndromic mental retardation. This deletion results in the truncation of the helix-loop-helix DNA binding and the C2 domains, crucial for Freud-1 repressor activity, and hence is predicted to generate an inactive or weakly dominant negative protein. The possible mechanisms by which inactivation of Freud-1 could lead to abnormal cortical development and cognitive impairment and the potential roles of Freud-1 gene targets are discussed.
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Affiliation(s)
- Anastasia Rogaeva
- Ottawa Health Research Institute (Neuroscience) and Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Ontario, Canada
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Abstract
The identification of the genes mutated in autosomal recessive non-syndromic mental retardation (ARNSMR) has been very active recently. This report presents an overview of the current knowledge on clinical data in ARNSMR and progress in research. To date, 12 ARNSMR loci have been mapped, and three genes identified. Mutations in known ARNSMR genes have been detected so far in only a small number of families; their contribution to mental retardation in the general population might be limited. The ARNSMR-causing genes belong to different protein families, including serine proteases, Adenosine 5'-triphosphate-dependent Lon proteases and calcium-regulated transcriptional repressors. All of the mutations in the ARNSMR-causing genes are protein truncating, indicating a putative severe loss-of-function effect. The future objective will be the development of diagnostic kits for molecular diagnosis in mentally retarded individuals in order to offer at-risk families pre-natal diagnosis to detect affected offspring.
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Rogaeva A, Albert PR. The mental retardation gene CC2D1A/Freud-1 encodes a long isoform that binds conserved DNA elements to repress gene transcription. Eur J Neurosci 2007; 26:965-74. [PMID: 17714190 DOI: 10.1111/j.1460-9568.2007.05727.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The CC2D1A/Freud-1 gene has recently been linked to non-syndromic mental retardation and a short isoform of mouse Five prime REpressor Under Dual repression binding protein 1 (Freud-1) can repress the serotonin-1A (5-HT1A) receptor gene in rodent cells. In this study, we addressed the expression, localization and regulation of the human 5-HT1A receptor gene by a long isoform of human Freud-1 protein (Freud-1L). We show that human CC2D1A/Freud-1 RNA is expressed in brain and peripheral tissues and encodes short and long isoforms, which differ by an upstream in-frame translational start site. Whereas previous studies identified the short isoform of Freud-1 as the predominant isoform in rodent cells, we demonstrate that the long isoform is more abundant in human cells, especially in the nuclear fraction. The nuclear localization of Freud-1L was enriched upon inhibition of chromosome region maintenance 1/exportin 1-dependent nuclear export, indicating a dynamic regulation of Freud-1 nuclear localization. Consistent with a functional role in the nucleus, human Freud-1L bound specifically to its dual repressor element in the 5-HT1A receptor gene in vitro and repressed transcription from these sites. Importantly, chromatin immunoprecipitation using antibodies specific for human Freud-1L demonstrated that it is bound to the dual repressor element in chromatin, indicating a functional role in regulating the basal expression of the 5-HT1A receptor gene. Taken together, these results indicate that both the short and long isoforms of Freud-1 are expressed, although Freud-1L is the major isoform that regulates the human 5-HT1A receptor gene. Disruption of transcriptional regulation by mutation of Freud-1 may play a role in abnormal brain function leading to mental retardation.
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Affiliation(s)
- Anastasia Rogaeva
- Ottawa Health Research Institute (Neuroscience), and Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, Canada
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Xin W, Xiaohua N, Peilin C, Xin C, Yaqiong S, Qihan W. Primary function analysis of human mental retardation related gene CRBN. Mol Biol Rep 2007; 35:251-6. [PMID: 17380424 DOI: 10.1007/s11033-007-9077-3] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2006] [Accepted: 02/27/2007] [Indexed: 11/21/2022]
Abstract
The mutation of human cereblon gene (CRBN) is revealed to be related with mild mental retardation. Since the molecular characteristics of CRBN have not been well presented, we investigated the general properties of CRBN. We analyzed its gene structure and protein homologues. The CRBN protein might belong to a family of adenosine triphosphate (ATP)-dependent Lon protease. We also found that CRBN was widely expressed in different tissues, and the expression level in testis is significantly higher than other tissues. This may suggested it could play some important roles in several other tissues besides brain. Transient transfection experiment in AD 293 cell lines suggested that both CRBN and CRBN mutant (nucleotide position 1,274(C > T)) are located in the whole cells. This may suggest new functions of CRBN in cell nucleolus besides its mitochondria protease activity in cytoplasm.
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Affiliation(s)
- Wang Xin
- Laboratory of Gene Function, School of Life Sciences, East China Normal University, Shanghai, 200062, P.R. China
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12
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Uyguner O, Kayserili H, Li Y, Karaman B, Nürnberg G, Hennies H, Becker C, Nürnberg P, Başaran S, Apak MY, Wollnik B. A new locus for autosomal recessive non-syndromic mental retardation maps to 1p21.1-p13.3. Clin Genet 2007; 71:212-9. [PMID: 17309643 DOI: 10.1111/j.1399-0004.2007.00762.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Autosomal recessive inheritance of non-syndromic mental retardation (ARNSMR) may account for approximately 25% of all patients with non-specific mental retardation (NSMR). Although many X-linked genes have been identified as a cause of NSMR, only three autosomal genes are known to cause ARNSMR. We present here a large consanguineous Turkish family with four mentally retarded individuals from different branches of the family. Clinical tests showed cognitive impairment but no neurological, skeletal, and biochemical involvements. Genome-wide mapping using Human Mapping 10K Array showed a single positive locus with a parametric LOD score of 4.92 in a region on chromosome 1p21.1-p13.3. Further analyses using polymorphic microsatellite markers defined a 6.6-Mb critical region containing approximately 130 known genes. This locus is the fourth one linked to ARNSMR.
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Affiliation(s)
- O Uyguner
- Istanbul Medical Faculty, Medical Genetics Department, Istanbul University, Istanbul, Turkey.
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Sun Y, Zhang F, Gao J, Gao X, Guo T, Shi Y, Tang W, Li S, Zheng Z, Zheng Y, Li X, Feng G, He L. Variants in the RAB3A gene are not associated with mental retardation in the Chinese population. Neurosci Lett 2006; 401:114-8. [PMID: 16584842 DOI: 10.1016/j.neulet.2006.02.079] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2005] [Revised: 02/28/2006] [Accepted: 02/28/2006] [Indexed: 10/24/2022]
Abstract
Mental retardation is a common form of cognitive impairment among children. The underlying causes of mental retardation are extremely heterogeneous, and include significant genetic factors. The coexistence of neuropathology and cognitive deficits supports the view that mental retardation is a disorder of brain development and plasticity. Rab3A, a member of the Rab small G protein family, is a key molecule in modulating basal neurotransmission and contributes to synaptic plasticity. The RAB3A gene is located on chromosome 19p13.11, near a region shown by a linkage study to be involved in the etiology of mental retardation. Because of both its function and chromosomal location, RAB3A is a potential candidate susceptibility gene for mental retardation. To investigate the possible genetic contribution of the RAB3A gene, we performed a case-control association study focused on the Han population of northwestern China using four common SNPs in the gene (rs7259012, rs17683539, rs2271882, and rs874628). Pairwise linkage disequilibrium analysis showed that the four SNPs were in linkage disequilibrium. However, there were no significant differences of either allele or genotype frequencies at any of the SNPs nor any significant differences in haplotype distributions between cases and controls. In conclusion, we have found no evidence for RAB3A conferring susceptibility on mental retardation in the Han Chinese population.
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Affiliation(s)
- Yun Sun
- Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 294 Taiyuan Road, Shanghai 200031, China
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Higgins JJ, Pucilowska J, Lombardi RQ, Rooney JP. A mutation in a novel ATP-dependent Lon protease gene in a kindred with mild mental retardation. Neurology 2005; 63:1927-31. [PMID: 15557513 PMCID: PMC1201536 DOI: 10.1212/01.wnl.0000146196.01316.a2] [Citation(s) in RCA: 186] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
BACKGROUND Identifying the genetic factors that contribute to memory and learning is limited by the complexity of brain development and the lack of suitable human models for mild disorders of cognition. METHODS Previously, a disease locus was mapped for a mild type of nonsyndromic mental retardation (IQ between 50 and 70) to a 4.2-MB interval on chromosome 3p25-pter in a large kindred. The genes and transcripts within the candidate region were systematically analyzed for mutations by single-strand polymorphism analysis and DNA sequencing. RESULTS A nonsense mutation causing a premature stop codon in a novel gene (cereblon; CRBN) was identified that encodes for an ATP-dependent Lon protease. The predicted protein sequence is highly conserved across species, and it belongs to a family of proteins that selectively degrade short-lived polypeptides and regulate mitochondrial replication and transcription. One member of the Lon-containing protein family is regionally expressed in the human hippocampus, an important neuroanatomic region that is involved in long-term potentiation and learning. The mutation in the CRBN gene described interrupts an N-myristoylation site and eliminates a casein kinase II phosphorylation site at the C terminus. CONCLUSIONS A gene on chromosome 3p that is associated with mild mental retardation in a large kindred is reported. This finding implicates a role for the ATP-dependent degradation of proteins in memory and learning.
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Affiliation(s)
- Joseph J Higgins
- Center for Human Genetics and Child Neurology, Mid-Hudson Family Health Institute, 279 Main St., Suite 203A, New Paltz, NY 12561, USA.
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15
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Basel-Vanagaite L, Attia R, Yahav M, Ferland RJ, Anteki L, Walsh CA, Olender T, Straussberg R, Magal N, Taub E, Drasinover V, Alkelai A, Bercovich D, Rechavi G, Simon AJ, Shohat M. The CC2D1A, a member of a new gene family with C2 domains, is involved in autosomal recessive non-syndromic mental retardation. J Med Genet 2005; 43:203-10. [PMID: 16033914 PMCID: PMC2563235 DOI: 10.1136/jmg.2005.035709] [Citation(s) in RCA: 115] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
BACKGROUND The molecular basis of autosomal recessive non-syndromic mental retardation (NSMR) is poorly understood, mostly owing to heterogeneity and absence of clinical criteria for grouping families for linkage analysis. Only two autosomal genes, the PRSS12 gene on chromosome 4q26 and the CRBN on chromosome 3p26, have been shown to cause autosomal recessive NSMR, each gene in only one family. OBJECTIVE To identify the gene causing autosomal recessive NSMR on chromosome 19p13.12. RESULTS The candidate region established by homozygosity mapping was narrowed down from 2.4 Mb to 0.9 Mb on chromosome 19p13.12. A protein truncating mutation was identified in the gene CC2D1A in nine consanguineous families with severe autosomal recessive NSMR. The absence of the wild type protein in the lymphoblastoid cells of the patients was confirmed. CC2D1A is a member of a previously uncharacterised gene family that carries two conserved motifs, a C2 domain and a DM14 domain. The C2 domain is found in proteins which function in calcium dependent phospholipid binding; the DM14 domain is unique to the CC2D1A protein family and its role is unknown. CC2D1A is a putative signal transducer participating in positive regulation of I-kappaB kinase/NFkappaB cascade. Expression of CC2D1A mRNA was shown in the embryonic ventricular zone and developing cortical plate in staged mouse embryos, persisting into adulthood, with highest expression in the cerebral cortex and hippocampus. CONCLUSIONS A previously unknown signal transduction pathway is important in human cognitive development.
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Affiliation(s)
- L Basel-Vanagaite
- Department of Medical Genetics, Rabin Medical Centre, Beilinson Campus, Petah Tikva 49100, Israel.
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16
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Abstract
X-linked mental retardation (XLMR) is a very heterogeneous condition, subdivided in two categories mainly based on clinical features: syndromic XLMR (MRXS) and non-syndromic XLMR (MRX). Although it was thought that 20-25% of mental retardation (MR) in males was caused by monogenetic X-linked factors, recent estimations are lower: in the range of 10-12%. The number of identified genes involved in XLMR has been rapidly growing in the past years. Subsequently, an increasing number of patients and families have been reported in which mutations in XLMR genes have been identified. It was observed previously, that mutations in several of XLMR genes can result in syndromic and in non-syndromic phenotypes. This observation has been confirmed for the more recently identified genes. Therefore, in this review, focus has been given on the clinical data and on phenotype-genotype correlations for those genes implicated in both non-syndromic and syndromic XLMR.
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Affiliation(s)
- T Kleefstra
- Department of Human Genetics, Radboud University Medical Center Nijmegen, the Netherlands
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Higgins JJ, Pucilowska J, Lombardi RQ, Rooney JP. Candidate genes for recessive non-syndromic mental retardation on chromosome 3p (MRT2A). Clin Genet 2004; 65:496-500. [PMID: 15151510 DOI: 10.1111/j.0009-9163.2004.00267.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A mild type of autosomal recessive, non-syndromic mental retardation (NSMR) is linked to loci on chromosome 3p. This report delimits the MRT2A minimal critical region to 4.2 Mb between loci D3S3630 and D3S1304. This interval contains nine genes (IL5RA, TRNT1, LRRN1, SETMAR, SUMF1, ITPR1, BHLHB2, EDEM, and MRPS36P1). The results suggest that a mutation does not exist in these genes and that an unknown transcript in the region contributes to the cognitive deficits in NSMR.
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Affiliation(s)
- J J Higgins
- Center for Human Genetics and Child Neurology, Mid-Hudson Family Health Institute, 279 Main Street, New Paltz, NY 12561, USA.
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