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Chaisrisawadisuk S, Khampalikit I, Chankaew E, Moore MH. Secondary metopic craniosynostosis after posterior cranial decompression in cloverleaf skull deformity. Childs Nerv Syst 2024; 40:1937-1941. [PMID: 38324062 DOI: 10.1007/s00381-024-06309-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/04/2024] [Accepted: 01/29/2024] [Indexed: 02/08/2024]
Abstract
Cloverleaf skull deformity or Kleeblattschadel syndrome is a severe condition where multiple cranial sutures are absent and prematurely fused, leading to a trilobate head shape. The remaining open sutures or fontanelles compensate for rapid brain expansion, while the constricted fused calvarium restricts brain growth and results in increased intracranial pressure. Recent data show that early posterior cranial and foramen magnum decompression positively affects infants with cloverleaf skulls. However, long-term sequelae are still rarely discussed. We hereby report a child who developed secondary metopic craniosynostosis after posterior cranial decompression, which required a front-orbital advancement and cranial remodelling as a definitive procedure.
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Affiliation(s)
- Sarut Chaisrisawadisuk
- Division of Plastic Surgery, Department of Surgery, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand.
- Cleft and Craniofacial South Australia, Women's and Children's Hospital, North Adelaide, SA, Australia.
| | - Inthira Khampalikit
- Division of Neurosurgery, Department of Surgery, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Ekawut Chankaew
- Division of Neurosurgery, Department of Surgery, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Mark H Moore
- Cleft and Craniofacial South Australia, Women's and Children's Hospital, North Adelaide, SA, Australia
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Udaykumar N, Zaidi MAA, Rai A, Sen J. CNKSR2, a downstream mediator of retinoic acid signaling, modulates the Ras/Raf/MEK pathway to regulate patterning and invagination of the chick forebrain roof plate. Development 2023; 150:286897. [PMID: 36734326 DOI: 10.1242/dev.200857] [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: 04/13/2022] [Accepted: 01/03/2023] [Indexed: 02/04/2023]
Abstract
During embryonic development, the forebrain roof plate undergoes invagination, leading to separation of the cerebral hemispheres. Any defects in this process, in humans, lead to middle interhemispheric holoprosencephaly (MIH-HPE). In this study, we have identified a previously unreported downstream mediator of retinoic acid (RA) signaling, CNKSR2, which is expressed in the forebrain roof plate in the chick embryo. Knockdown of CNKSR2 affects invagination, cell proliferation and patterning of the roof plate, similar to the phenotypes observed upon inhibition of RA signaling. We further demonstrate that CNKSR2 functions by modulating the Ras/Raf/MEK signaling. This appears to be crucial for patterning of the forebrain roof plate and its subsequent invagination, leading to the formation of the cerebral hemispheres. Thus, a set of novel molecular players have been identified that regulate the morphogenesis of the avian forebrain.
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Affiliation(s)
- Niveda Udaykumar
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology Kanpur, Kanpur 208016 Uttar Pradesh, India
| | - Mohd Ali Abbas Zaidi
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology Kanpur, Kanpur 208016 Uttar Pradesh, India
| | - Aishwarya Rai
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology Kanpur, Kanpur 208016 Uttar Pradesh, India
| | - Jonaki Sen
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology Kanpur, Kanpur 208016 Uttar Pradesh, India
- Mehta Family Center for Engineering in Medicine (MFCEM), Indian Institute of Technology Kanpur, Kanpur 208016, Uttar Pradesh, India
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3
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de Castro VF, Mattos D, de Carvalho FM, Cavalcanti DP, Duenas-Roque MM, Llerena J, Cosentino VR, Honjo RS, Leite JCL, Sanseverino MT, de Souza MPA, Bernardi P, Bolognese AM, Santana da Silva LC, Barbero P, Correia PS, Bueno LSM, Savastano CP, Orioli IM. New SHH and Known SIX3 Variants in a Series of Latin American Patients with Holoprosencephaly. Mol Syndromol 2021; 12:219-233. [PMID: 34421500 DOI: 10.1159/000515044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Accepted: 02/04/2021] [Indexed: 11/19/2022] Open
Abstract
Holoprosencephaly (HPE) is the failure of the embryonic forebrain to develop into 2 hemispheres promoting midline cerebral and facial defects. The wide phenotypic variability and causal heterogeneity make genetic counseling difficult. Heterozygous variants with incomplete penetrance and variable expressivity in the SHH, SIX3, ZIC2, and TGIF1 genes explain ∼25% of the known causes of nonchromosomal HPE. We studied these 4 genes and clinically described 27 Latin American families presenting with nonchromosomal HPE. Three new SHH variants and a third known SIX3 likely pathogenic variant found by Sanger sequencing explained 15% of our cases. Genotype-phenotype correlation in these 4 families and published families with identical or similar driver gene, mutated domain, conservation of residue in other species, and the type of variant explain the pathogenicity but not the phenotypic variability. Nine patients, including 2 with SHH pathogenic variants, presented benign variants of the SHH, SIX3, ZIC2, and TGIF1 genes with potential alteration of splicing, a causal proposition in need of further studies. Finding more families with the same SIX3 variant may allow further identification of genetic or environmental modifiers explaining its variable phenotypic expression.
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Affiliation(s)
- Viviane Freitas de Castro
- ECLAMC at Departamento de Genética, UFRJ, Rio de Janeiro, Brazil.,Instituto Nacional de Genética Médica Populacional INAGEMP, Porto Alegre, Brazil
| | - Daniel Mattos
- ECLAMC at Departamento de Genética, UFRJ, Rio de Janeiro, Brazil.,Instituto Nacional de Genética Médica Populacional INAGEMP, Porto Alegre, Brazil
| | - Flavia Martinez de Carvalho
- Instituto Nacional de Genética Médica Populacional INAGEMP, Porto Alegre, Brazil.,ECLAMC at Laboratorio Epidemiol. Malformações Congênitas, IOC/FIOCRUZ, Rio de Janeiro, Brazil
| | | | - Milagros M Duenas-Roque
- ECLAMC at Servicio de Genética, Hospital Nacional Edgardo Rebagliati Martins/EsSalud, Lima, Peru
| | - Juan Llerena
- Instituto Nacional de Genética Médica Populacional INAGEMP, Porto Alegre, Brazil.,ECLAMC at Centro de Genética Médica, IFF/FIOCRUZ, Rio de Janeiro, Brazil
| | | | | | | | | | | | - Pricila Bernardi
- Núcleo de Genética Clínica, Departamento de Clínica Médica/UFSC, Florianópolis, Brazil
| | - Ana Maria Bolognese
- Departamento de Ortodontia, Faculdade de Odontologia/UFRJ, Rio de Janeiro, Brazil
| | - Luiz Carlos Santana da Silva
- Instituto Nacional de Genética Médica Populacional INAGEMP, Porto Alegre, Brazil.,Laboratório de Erros Inatos de Metabolismo, Instituto de Ciências Biológicas/UFP, Belém, Brazil
| | - Pablo Barbero
- RENAC, Centro Nacional de Genética Médica Dr. Eduardo E. Castilla/MS, Buenos Aires, Argentina
| | | | | | | | - Iêda Maria Orioli
- ECLAMC at Departamento de Genética, UFRJ, Rio de Janeiro, Brazil.,Instituto Nacional de Genética Médica Populacional INAGEMP, Porto Alegre, Brazil
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4
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Li Y, Wang R, Qiao N, Peng G, Zhang K, Tang K, Han JDJ, Jing N. Transcriptome analysis reveals determinant stages controlling human embryonic stem cell commitment to neuronal cells. J Biol Chem 2017; 292:19590-19604. [PMID: 28972157 PMCID: PMC5712601 DOI: 10.1074/jbc.m117.796383] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Revised: 09/17/2017] [Indexed: 12/22/2022] Open
Abstract
Proper neural commitment is essential for ensuring the appropriate development of the human brain and for preventing neurodevelopmental diseases such as autism spectrum disorders, schizophrenia, and intellectual disorders. However, the molecular mechanisms underlying the neural commitment in humans remain elusive. Here, we report the establishment of a neural differentiation system based on human embryonic stem cells (hESCs) and on comprehensive RNA sequencing analysis of transcriptome dynamics during early hESC differentiation. Using weighted gene co-expression network analysis, we reveal that the hESC neurodevelopmental trajectory has five stages: pluripotency (day 0); differentiation initiation (days 2, 4, and 6); neural commitment (days 8-10); neural progenitor cell proliferation (days 12, 14, and 16); and neuronal differentiation (days 18, 20, and 22). These stages were characterized by unique module genes, which may recapitulate the early human cortical development. Moreover, a comparison of our RNA-sequencing data with several other transcriptome profiling datasets from mice and humans indicated that Module 3 associated with the day 8-10 stage is a critical window of fate switch from the pluripotency to the neural lineage. Interestingly, at this stage, no key extrinsic signals were activated. In contrast, using CRISPR/Cas9-mediated gene knockouts, we also found that intrinsic hub transcription factors, including the schizophrenia-associated SIX3 gene and septo-optic dysplasia-related HESX1 gene, are required to program hESC neural determination. Our results improve the understanding of the mechanism of neural commitment in the human brain and may help elucidate the etiology of human mental disorders and advance therapies for managing these conditions.
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Affiliation(s)
- Yuanyuan Li
- From the State Key Laboratory of Cell Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology and
| | - Ran Wang
- From the State Key Laboratory of Cell Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology and
| | - Nan Qiao
- Chinese Academy of Sciences Key Laboratory of Computational Biology, Chinese Academy of Sciences-Max Planck Partner Institute for Computational Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 320 Yue Yang Road, Shanghai 200031
| | - Guangdun Peng
- From the State Key Laboratory of Cell Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology and
| | - Ke Zhang
- From the State Key Laboratory of Cell Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology and
| | - Ke Tang
- the Institute of Life Science, Nanchang University, Nanchang, Jiangxi 330031, and
| | - Jing-Dong J Han
- Chinese Academy of Sciences Key Laboratory of Computational Biology, Chinese Academy of Sciences-Max Planck Partner Institute for Computational Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 320 Yue Yang Road, Shanghai 200031
| | - Naihe Jing
- From the State Key Laboratory of Cell Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology and
- the School of Life Science and Technology, ShanghaiTech University, 100 Haike Road, Shanghai 201210, China
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5
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Geng X, Acosta S, Lagutin O, Gil HJ, Oliver G. Six3 dosage mediates the pathogenesis of holoprosencephaly. Development 2016; 143:4462-4473. [PMID: 27770010 PMCID: PMC5201039 DOI: 10.1242/dev.132142] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2015] [Accepted: 10/12/2016] [Indexed: 01/06/2023]
Abstract
Holoprosencephaly (HPE) is defined as the incomplete separation of the two cerebral hemispheres. The pathology of HPE is variable and, based on the severity of the defect, HPE is divided into alobar, semilobar, and lobar. Using a novel hypomorphic Six3 allele, we demonstrate in mice that variability in Six3 dosage results in different HPE phenotypes. Furthermore, we show that whereas the semilobar phenotype results from severe downregulation of Shh expression in the rostral diencephalon ventral midline, the alobar phenotype is caused by downregulation of Foxg1 expression in the anterior neural ectoderm. Consistent with these results, in vivo activation of the Shh signaling pathway rescued the semilobar phenotype but not the alobar phenotype. Our findings show that variations in Six3 dosage result in different forms of HPE.
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Affiliation(s)
- Xin Geng
- Oklahoma Medical Research Foundation, Oklahoma City, OK 73104, USA
| | - Sandra Acosta
- Center for Vascular and Developmental Biology, Feinberg Cardiovascular Research Institute, Northwestern University, Chicago, IL 60611, USA
| | - Oleg Lagutin
- Department of Genetics, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Hyea Jin Gil
- Center for Vascular and Developmental Biology, Feinberg Cardiovascular Research Institute, Northwestern University, Chicago, IL 60611, USA
| | - Guillermo Oliver
- Center for Vascular and Developmental Biology, Feinberg Cardiovascular Research Institute, Northwestern University, Chicago, IL 60611, USA
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6
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Mouden C, Dubourg C, Carré W, Rose S, Quelin C, Akloul L, Hamdi-Rozé H, Viot G, Salhi H, Darnault P, Odent S, Dupé V, David V. Complex mode of inheritance in holoprosencephaly revealed by whole exome sequencing. Clin Genet 2016; 89:659-68. [DOI: 10.1111/cge.12722] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2015] [Revised: 12/28/2015] [Accepted: 12/30/2015] [Indexed: 12/12/2022]
Affiliation(s)
- C. Mouden
- UMR6290 Institut de Génétique et Développement de Rennes; Université de Rennes 1; Rennes France
| | - C. Dubourg
- UMR6290 Institut de Génétique et Développement de Rennes; Université de Rennes 1; Rennes France
- Laboratoire de Génétique Moléculaire et Génomique; C.H.U. de Rennes; Rennes France
| | - W. Carré
- Laboratoire de Génétique Moléculaire et Génomique; C.H.U. de Rennes; Rennes France
| | - S. Rose
- UMR1085 Institut de Recherche sur la Santé, l'Environnement et le Travail; Université de Rennes 1; Rennes France
| | - C. Quelin
- Service de Génétique Clinique; C.H.U. de Rennes; Rennes France
| | - L. Akloul
- Service de Génétique Clinique; C.H.U. de Rennes; Rennes France
| | - H. Hamdi-Rozé
- UMR6290 Institut de Génétique et Développement de Rennes; Université de Rennes 1; Rennes France
- Laboratoire de Génétique Moléculaire et Génomique; C.H.U. de Rennes; Rennes France
| | - G. Viot
- Service de Génétique Médicale; Maternité Port Royal; Paris France
| | - H. Salhi
- Foetopathologie et Anatomie Pathologique Pédiatrique; Hôpital Cochin; Paris France
| | - P. Darnault
- Service de Radiologie et Imagerie Médicale; C.H.U. de Rennes; Rennes France
| | - S. Odent
- UMR6290 Institut de Génétique et Développement de Rennes; Université de Rennes 1; Rennes France
- Service de Génétique Clinique; C.H.U. de Rennes; Rennes France
| | - V. Dupé
- UMR6290 Institut de Génétique et Développement de Rennes; Université de Rennes 1; Rennes France
| | - V. David
- UMR6290 Institut de Génétique et Développement de Rennes; Université de Rennes 1; Rennes France
- Laboratoire de Génétique Moléculaire et Génomique; C.H.U. de Rennes; Rennes France
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7
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Gold KS, Brand AH. Optix defines a neuroepithelial compartment in the optic lobe of the Drosophila brain. Neural Dev 2014; 9:18. [PMID: 25074684 PMCID: PMC4127074 DOI: 10.1186/1749-8104-9-18] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2014] [Accepted: 06/25/2014] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND During early brain development, the organisation of neural progenitors into a neuroepithelial sheet maintains tissue integrity during growth. Neuroepithelial cohesion and patterning is essential for orderly proliferation and neural fate specification. Neuroepithelia are regionalised by the expression of transcription factors and signalling molecules, resulting in the formation of distinct developmental, and ultimately functional, domains. RESULTS We have discovered that the Six3/6 family orthologue Optix is an essential regulator of neuroepithelial maintenance and patterning in the Drosophila brain. Six3 and Six6 are required for mammalian eye and forebrain development, and mutations in humans are associated with severe eye and brain malformation. In Drosophila, Optix is expressed in a sharply defined region of the larval optic lobe, and its expression is reciprocal to that of the transcription factor Vsx1. Optix gain- and loss-of-function affects neuroepithelial adhesion, integrity and polarity. We find restricted cell lineage boundaries that correspond to transcription factor expression domains. CONCLUSION We propose that the optic lobe is compartmentalised by expression of Optix and Vsx1. Our findings provide insight into the spatial patterning of a complex region of the brain, and suggest an evolutionarily conserved principle of visual system development.
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Affiliation(s)
| | - Andrea H Brand
- The Gurdon Institute and Department of Physiology, Development & Neuroscience, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK.
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8
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Xu PX. The EYA-SO/SIX complex in development and disease. Pediatr Nephrol 2013; 28:843-54. [PMID: 22806561 PMCID: PMC6592036 DOI: 10.1007/s00467-012-2246-1] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/16/2012] [Revised: 06/10/2012] [Accepted: 06/12/2012] [Indexed: 10/28/2022]
Abstract
Eyes absent (EYA) and Sine oculis (SO/SIX) proteins function as transcriptional activation complexes and play essential roles in organogenesis during embryonic development in regulating cell proliferation and survival and coordination of particular differentiation programs. Mutations of the Eya and So/Six genes cause profound developmental defects in organisms as diverse as flies, frogs, fish, mice, and humans. EYA proteins also possess an intrinsic phosphatase activity, which is essential for normal development. Here, we review crucial roles of EYA and SO/SIX in development and disease in mice and humans.
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Affiliation(s)
- Pin-Xian Xu
- Department of Genetics and Genomic Sciences and Developmental and Regenerative Biology, Mount Sinai School of Medicine, New York, NY 10029, USA.
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Holton NE, Yokley TR, Figueroa A. Nasal septal and craniofacial form in European- and African-derived populations. J Anat 2012; 221:263-74. [PMID: 22747629 DOI: 10.1111/j.1469-7580.2012.01533.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
As a component of the chondrocranium, the nasal septum influences the anteroposterior dimensions of the facial skeleton. The role of the septum as a facial growth center, however, has been studied primarily in long-snouted mammals, and its precise influence on human facial growth is not as well understood. Whereas the nasal septum may be important in the anterior growth of the human facial skeleton early in ontogeny, the high incidence of nasal septal deviation in humans suggests the septum's influence on human facial length is limited to the early phases of facial growth. Nevertheless, the nasal septum follows a growth trajectory similar to the facial skeleton and, as such, its prolonged period of growth may influence other aspects of facial development. Using computed tomography scans of living human subjects (n = 70), the goal of the present study is to assess the morphological relationship between the nasal septum and facial skeleton in European- and African-derived populations, which have been shown to exhibit early developmental differences in the nasal septal-premaxillary complex. First we assessed whether there is population variation in the size of the nasal septum in European- and African-derived samples. This included an evaluation of septal deviation and the spatial constraints that influence variation in this condition. Next, we assessed the relationship between nasal septal size and craniofacial shape using multivariate regression techniques. Our results indicate that there is significant population variation in septal size and magnitude of septal deviation, both of which are greater in the European-derived sample. While septal deviation suggests a disjunction between the nasal septum and other components of the facial skeleton, we nevertheless found a significant relationship between the size of the nasal septum and craniofacial shape, which appears to largely be a response to the need to accommodate variation in nasal septal size.
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Affiliation(s)
- Nathan E Holton
- Department of Orthodontics, University of Iowa, Iowa City, IA, USA.
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Williams PG, Wetherbee JJ, Rosenfeld JA, Hersh JH. 20p11 deletion in a female child with panhypopituitarism, cleft lip and palate, dysmorphic facial features, global developmental delay and seizure disorder. Am J Med Genet A 2011; 155A:186-91. [PMID: 21204230 DOI: 10.1002/ajmg.a.33763] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Deletions of 20p are rare with the majority of reported cases involving individuals with 20p12 deletions associated with Alagille syndrome. We report on a child with a de novo mosaic 20p11 deletion who presents with panhypopituitarism; hypoplastic pituitary gland and ectopic posterior pituitary gland on MRI of the brain; cleft lip and palate; kyphosis with anterior beaking of L1 and L2 vertebral bodies; pulmonic stenosis; dysmorphic facial features including flat nasal bridge, hypoplastic premaxilla, hypotelorism, preauricular pit, and cupped ears; seizure disorder; variable muscle tone; and global developmental delay. Array comparative genomic hybridization revealed this deletion to be approximately 5.4 Mb in size, containing 35 genes. Previously, an infant with 20p11.22 deletion who had panhypopituitarism, craniofacial, and genital abnormalities was reported, but the precise parameters of that deletion are unavailable. Several other reported cases of 20p11 deletions also have phenotypic overlap with our case. The similarities in clinical features of these patients suggest that the genes at 20p11 have a critical role in development of midline brain structures.
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Affiliation(s)
- P G Williams
- Department of Pediatrics, University of Louisville, Kentucky.
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Abstract
In vertebrate hedgehog signaling, hedgehog ligands are processed to become bilipidated and then multimerize, which allows them to leave the signaling cell via Dispatched 1 and become transported via glypicans and megalin to the responding cells. Hedgehog then interacts with a complex of Patched 1 and Cdo/Boc, which activates endocytic Smoothened to the cilium. Patched 1 regulates the activity of Smoothened (1) via Vitamin D3, which inhibits Smoothened in the absence of hedgehog ligand or (2) via oxysterols, which activate Smoothened in the presence of hedgehog ligand. Hedgehog ligands also interact with Hip1, Patched 2, and Gas1, which regulate the range as well as the level of hedgehog signaling. In vertebrates, Smoothened is shortened at its C-terminal end and lacks most of the phosphorylation sites of importance in Drosophila. Cos2, also of importance in Drosophila, plays no role in mammalian transduction, nor do its homologs Kif7 and Kif27. The cilium may provide a function analogous to that of Cos2 by linking Smoothened to the modulation of Gli transcription factors. Disorders associated with the hedgehog signaling network follow, including nevoid basal cell carcinoma syndrome, holoprosencephaly, Smith-Lemli-Opitz syndrome, Greig cephalopolysyndactyly syndrome, Pallister-Hall syndrome, Carpenter syndrome, and Rubinstein-Taybi syndrome.
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Affiliation(s)
- M Michael Cohen
- Department of Pediatrics, Faculty of Medicine, Dalhousie University, Halifax, Nova Scotia, Canada.
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12
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Paulussen ADC, Schrander-Stumpel CT, Tserpelis DCJ, Spee MKM, Stegmann APA, Mancini GM, Brooks AS, Collée M, Maat-Kievit A, Simon MEH, van Bever Y, Stolte-Dijkstra I, Kerstjens-Frederikse WS, Herkert JC, van Essen AJ, Lichtenbelt KD, van Haeringen A, Kwee ML, Lachmeijer AMA, Tan-Sindhunata GMB, van Maarle MC, Arens YHJM, Smeets EEJGL, de Die-Smulders CE, Engelen JJM, Smeets HJ, Herbergs J. The unfolding clinical spectrum of holoprosencephaly due to mutations in SHH, ZIC2, SIX3 and TGIF genes. Eur J Hum Genet 2010; 18:999-1005. [PMID: 20531442 PMCID: PMC2987413 DOI: 10.1038/ejhg.2010.70] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2010] [Revised: 03/23/2010] [Accepted: 03/25/2010] [Indexed: 11/09/2022] Open
Abstract
Holoprosencephaly is a severe malformation of the brain characterized by abnormal formation and separation of the developing central nervous system. The prevalence is 1:250 during early embryogenesis, the live-born prevalence is 1:16 000. The etiology of HPE is extremely heterogeneous and can be teratogenic or genetic. We screened four known HPE genes in a Dutch cohort of 86 non-syndromic HPE index cases, including 53 family members. We detected 21 mutations (24.4%), 3 in SHH, 9 in ZIC2 and 9 in SIX3. Eight mutations involved amino-acid substitutions, 7 ins/del mutations, 1 frame-shift, 3 identical poly-alanine tract expansions and 2 gene deletions. Pathogenicity of mutations was presumed based on de novo character, predicted non-functionality of mutated proteins, segregation of mutations with affected family-members or combinations of these features. Two mutations were reported previously. SNP array confirmed detected deletions; one spanning the ZIC2/ZIC5 genes (approx. 100 kb) the other a 1.45 Mb deletion including SIX2/SIX3 genes. The mutation percentage (24%) is comparable with previous reports, but we detected significantly less mutations in SHH: 3.5 vs 10.7% (P=0.043) and significantly more in SIX3: 10.5 vs 4.3% (P=0.018). For TGIF1 and ZIC2 mutation the rate was in conformity with earlier reports. About half of the mutations were de novo, one was a germ line mosaic. The familial mutations displayed extensive heterogeneity in clinical manifestation. Of seven familial index patients only two parental carriers showed minor HPE signs, five were completely asymptomatic. Therefore, each novel mutation should be considered as a risk factor for clinically manifest HPE, with the caveat of reduced clinical penetrance.
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Affiliation(s)
- Aimée D C Paulussen
- Department of Clinical Genetics, School for Oncology & Developmental Biology (GROW), Maastricht UMC, The Netherlands.
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Richieri-Costa A, Ribeiro LA. Holoprosencephaly and holoprosencephaly-like phenotypes: Review of facial and molecular findings in patients from a craniofacial hospital in Brazil. AMERICAN JOURNAL OF MEDICAL GENETICS PART C-SEMINARS IN MEDICAL GENETICS 2010; 154C:149-57. [PMID: 20104612 DOI: 10.1002/ajmg.c.30247] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Here we report on the clinical and genetic data for a large sample of Brazilian patients studied at the Hospital de Reabilitação de Anomalas Craniofaciais-Universidade de São Paulo (HRAC-USP) who presented with either the classic holoprosencephaly or the holoprosencephaly-like (HPE-L) phenotype. The sample included patients without detected mutations in some HPE determinant genes such as SHH, GLI2, SIX3, TGIF, and PTCH, as well as the photographic documentation of the previously reported patients in our Center. The HPE-L phenotype has been also called of HPE "minor forms" or "microforms." The variable phenotype, the challenge of genetic counseling, and the similarities to patients with isolated cleft lip/palate are discussed.
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Affiliation(s)
- Antonio Richieri-Costa
- Department of Clinical Genetics, Hospital de Reabilitação de Anornalias Craniofaciais, Universidade de São Paulo, Bauro, S.P., Brazil.
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Solomon BD, Mercier S, Vélez JI, Pineda-Alvarez DE, Wyllie A, Zhou N, Dubourg C, David V, Odent S, Roessler E, Muenke M. Analysis of genotype-phenotype correlations in human holoprosencephaly. AMERICAN JOURNAL OF MEDICAL GENETICS PART C-SEMINARS IN MEDICAL GENETICS 2010; 154C:133-41. [PMID: 20104608 DOI: 10.1002/ajmg.c.30240] [Citation(s) in RCA: 126] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Since the discovery of the first gene causing holoprosencephaly (HPE), over 500 patients with mutations in genes associated with non-chromosomal, non-syndromic HPE have been described, with detailed descriptions available in over 300. Comprehensive clinical analysis of these individuals allows examination for the presence of genotype-phenotype correlations. These correlations allow a degree of differentiation between patients with mutations in different HPE-associated genes and for the application of functional studies to determine intragenic correlations. These early correlations are an important advance in the understanding of the clinical aspects of this disease, and in general argue for continued analysis of the genetic and clinical findings of large cohorts of patients with rare diseases in order to better inform both basic biological insight and care and counseling for affected patients and families.
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Affiliation(s)
- Benjamin D Solomon
- National Human Genome Research Institute, National Institutes of Health, Bethesda, MD 20892, USA
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15
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Chen JM, Férec C, Cooper DN. Closely spaced multiple mutations as potential signatures of transient hypermutability in human genes. Hum Mutat 2009; 30:1435-48. [PMID: 19685533 DOI: 10.1002/humu.21088] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Data from diverse organisms suggests that transient hypermutability is a general mutational mechanism with the potential to generate multiple synchronous mutations, a phenomenon probably best exemplified by closely spaced multiple mutations (CSMMs). Here we have attempted to extend the concept of transient hypermutability from somatic cells to the germline, using human inherited disease-causing multiple mutations as a model system. Employing stringent criteria for data inclusion, we have retrospectively identified numerous potential examples of pathogenic CSMMs that exhibit marked similarities to the CSMMs reported in other systems. These examples include (1) eight multiple mutations, each comprising three or more components within a sequence tract of <100 bp; (2) three possible instances of "mutation showers"; and (3) numerous highly informative "homocoordinate" mutations. Using the proportion of CpG substitution as a crude indicator of the relative likelihood of transient hypermutability, we present evidence to suggest that CSMMs comprising at least one pair of mutations separated by < or =100 bp may constitute signatures of transient hypermutability in human genes. Although this analysis extends the generality of the concept of transient hypermutability and provides new insights into what may be considered a novel mechanism of mutagenesis underlying human inherited disease, it has raised serious concerns regarding current practices in mutation screening.
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Affiliation(s)
- Jian-Min Chen
- Institut National de la Santé et de la Recherche Médicale, U613, Brest, France.
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16
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Lacbawan F, Solomon BD, Roessler E, El-Jaick K, Domené S, Vélez JI, Zhou N, Hadley D, Balog JZ, Long R, Fryer A, Smith W, Omar S, McLean SD, Clarkson K, Lichty A, Clegg NJ, Delgado MR, Levey E, Stashinko E, Potocki L, Vanallen MI, Clayton-Smith J, Donnai D, Bianchi DW, Juliusson PB, Njølstad PR, Brunner HG, Carey JC, Hehr U, Müsebeck J, Wieacker PF, Postra A, Hennekam RCM, van den Boogaard MJH, van Haeringen A, Paulussen A, Herbergs J, Schrander-Stumpel CTRM, Janecke AR, Chitayat D, Hahn J, McDonald-McGinn DM, Zackai EH, Dobyns WB, Muenke M. Clinical spectrum of SIX3-associated mutations in holoprosencephaly: correlation between genotype, phenotype and function. J Med Genet 2009; 46:389-98. [PMID: 19346217 PMCID: PMC3510661 DOI: 10.1136/jmg.2008.063818] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
BACKGROUND Holoprosencephaly (HPE) is the most common structural malformation of the human forebrain. There are several important HPE mutational target genes, including the transcription factor SIX3, which encodes an early regulator of Shh, Wnt, Bmp and Nodal signalling expressed in the developing forebrain and eyes of all vertebrates. OBJECTIVE To characterise genetic and clinical findings in patients with SIX3 mutations. METHODS Patients with HPE and their family members were tested for mutations in HPE-associated genes and the genetic and clinical findings, including those for additional cases found in the literature, were analysed. The results were correlated with a mutation-specific functional assay in zebrafish. RESULTS In a cohort of patients (n = 800) with HPE, SIX3 mutations were found in 4.7% of probands and additional cases were found through testing of relatives. In total, 138 cases of HPE were identified, 59 of whom had not previously been clinically presented. Mutations in SIX3 result in more severe HPE than in other cases of non-chromosomal, non-syndromic HPE. An over-representation of severe HPE was found in patients whose mutations confer greater loss of function, as measured by the functional zebrafish assay. The gender ratio in this combined set of patients was 1.5:1 (F:M) and maternal inheritance was almost twice as common as paternal. About 14% of SIX3 mutations in probands occur de novo. There is a wide intrafamilial clinical range of features and classical penetrance is estimated to be at least 62%. CONCLUSIONS Our data suggest that SIX3 mutations result in relatively severe HPE and that there is a genotype-phenotype correlation, as shown by functional studies using animal models.
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Affiliation(s)
- F Lacbawan
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, 35 Convent Drive, MSC 3717, Building 35, Room 1B-203, Bethesda, MD 20892-3717, USA
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17
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Abstract
Holoprosencephaly (HPE), the most common human forebrain malformation, occurs in 1 in 250 fetuses and 1 in 16,000 live births. HPE is etiologically heterogeneous, and its pathology is variable. Several mouse models of HPE have been generated, and some of the molecular causes of different forms of HPE and the mechanisms underlying its variable pathology have been revealed by these models. Herein, we summarize the current knowledge on the genetic alterations that cause HPE and discuss some important questions about this disease that remain to be answered.
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Affiliation(s)
- Xin Geng
- Department of Genetics and Tumor Cell Biology, St. Jude Children's Research Hospital, Memphis, Tennessee 38105, USA
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18
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Solomon BD, Lacbawan F, Jain M, Domené S, Roessler E, Moore C, Dobyns WB, Muenke M. A novel SIX3 mutation segregates with holoprosencephaly in a large family. Am J Med Genet A 2009; 149A:919-25. [PMID: 19353631 PMCID: PMC2737713 DOI: 10.1002/ajmg.a.32813] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Holoprosencephaly is the most common structural malformation of the forebrain in humans and has a complex etiology including chromosomal aberrations, single gene mutations and environmental components. Here we present the pertinent clinical findings among members of an unusually large kindred ascertained over 15 years ago following the evaluation and subsequent genetic work-up of a female infant with congenital anomalies. A genome-wide scan and linkage analysis showed only suggestive evidence of linkage to markers on chromosome 2 among the most likely of several pedigree interpretations. We now report that a novel missense mutation in the SIX3 holoprosencephaly gene is the likely cause in this family. Molecular genetic analysis and/or clinical characterization now show that at least 15 members of this family are presumed SIX3 mutation gene carriers, with clinical manifestations ranging from phenotypically normal adults (non-penetrance) to alobar holoprosencephaly incompatible with postnatal life. This particular family represents a seminal example of the variable manifestations of gene mutations in holoprosencephaly and difficulties encountered in their elucidation.
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Affiliation(s)
- Benjamin D. Solomon
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland
| | - Felicitas Lacbawan
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland
- Department of Pathology, State University of New York Downstate Medical Center, Brooklyn, New York
| | - Mahim Jain
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland
| | - Sabina Domené
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland
| | - Erich Roessler
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland
| | - Cynthia Moore
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, Indiana
| | - William B. Dobyns
- Departments of Human Genetics, Neurology, and Pediatrics, The University of Chicago, Chicago, Illinois
| | - Maximilian Muenke
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland
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19
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Christensen KL, Patrick AN, McCoy EL, Ford HL. The six family of homeobox genes in development and cancer. Adv Cancer Res 2009; 101:93-126. [PMID: 19055944 DOI: 10.1016/s0065-230x(08)00405-3] [Citation(s) in RCA: 109] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
The homeobox gene superfamily encodes transcription factors that act as master regulators of development through their ability to activate or repress a diverse range of downstream target genes. Numerous families exist within the homeobox gene superfamily, and are classified on the basis of conservation of their homeodomains as well as additional motifs that contribute to DNA binding and to interactions with other proteins. Members of one such family, the Six family, form a transcriptional complex with Eya and Dach proteins, and together these proteins make up part of the retinal determination network first identified in Drosophila. This network is highly conserved in both invertebrate and vertebrate species, where it influences the development of numerous organs in addition to the eye, primarily through regulation of cell proliferation, survival, migration, and invasion. Mutations in Six, Eya, and Dach genes have been identified in a variety of human genetic disorders, demonstrating their critical role in human development. In addition, aberrant expression of Six, Eya, and Dach occurs in numerous human tumors, and Six1, in particular, plays a causal role both in tumor initiation and in metastasis. Emerging evidence for the importance of Six family members and their cofactors in numerous human tumors suggests that targeting of this complex may be a novel and powerful means to inhibit both tumor growth and progression.
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Affiliation(s)
- Kimberly L Christensen
- Program in Molecular Biology, University of Colorado School of Medicine, Denver, Colorado, USA
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20
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Domené S, Roessler E, El-Jaick KB, Snir M, Brown JL, Vélez JI, Bale S, Lacbawan F, Muenke M, Feldman B. Mutations in the human SIX3 gene in holoprosencephaly are loss of function. Hum Mol Genet 2008; 17:3919-28. [PMID: 18791198 PMCID: PMC2733808 DOI: 10.1093/hmg/ddn294] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2008] [Accepted: 09/09/2008] [Indexed: 01/12/2023] Open
Abstract
Holoprosencephaly (HPE) is the most common developmental anomaly of the human forebrain; however, the genetics of this heterogeneous and etiologically complex malformation is incompletely understood. Heterozygous mutations in SIX3, a transcription factor gene expressed in the anterior forebrain and eyes during early vertebrate development, have been frequently detected in human HPE cases. However, only a few mutations have been investigated with limited functional studies that would confirm a role in HPE pathogenesis. Here, we report the development of a set of robust and sensitive assays of human SIX3 function in zebrafish and apply these to the analysis of a total of 46 distinct mutations (19 previously published and 27 novel) located throughout the entire SIX3 gene. We can now confirm that 89% of these putative deleterious mutations are significant loss-of-function alleles. Since disease-associated single point mutations in the Groucho-binding eh1-like motif decreases the function in all assays, we can also confirm that this interaction is essential for human SIX3 co-repressor activity; we infer, in turn, that this function is important in HPE causation. We also unexpectedly detected truncated versions with partial function, yet missing a SIX3-encoded homeodomain. Our data indicate that SIX3 is a frequent target in the pathogenesis of HPE and demonstrate how this can inform the genetic counseling of families.
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Affiliation(s)
- Sabina Domené
- Medical Genetics Branch, National Human Genome Research Institute, Bethesda, MD 20892, USA
| | - Erich Roessler
- Medical Genetics Branch, National Human Genome Research Institute, Bethesda, MD 20892, USA
| | - Kenia B. El-Jaick
- Medical Genetics Branch, National Human Genome Research Institute, Bethesda, MD 20892, USA
| | - Mirit Snir
- Medical Genetics Branch, National Human Genome Research Institute, Bethesda, MD 20892, USA
| | - Jamie L. Brown
- Medical Genetics Branch, National Human Genome Research Institute, Bethesda, MD 20892, USA
| | - Jorge I. Vélez
- Medical Genetics Branch, National Human Genome Research Institute, Bethesda, MD 20892, USA
| | | | - Felicitas Lacbawan
- Medical Genetics Branch, National Human Genome Research Institute, Bethesda, MD 20892, USA
| | - Maximilian Muenke
- Medical Genetics Branch, National Human Genome Research Institute, Bethesda, MD 20892, USA
| | - Benjamin Feldman
- Medical Genetics Branch, National Human Genome Research Institute, Bethesda, MD 20892, USA
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21
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Geng X, Speirs C, Lagutin O, Inbal A, Liu W, Solnica-Krezel L, Jeong Y, Epstein D, Oliver G. Haploinsufficiency of Six3 fails to activate Sonic hedgehog expression in the ventral forebrain and causes holoprosencephaly. Dev Cell 2008; 15:236-47. [PMID: 18694563 PMCID: PMC2597207 DOI: 10.1016/j.devcel.2008.07.003] [Citation(s) in RCA: 133] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2008] [Revised: 06/13/2008] [Accepted: 07/12/2008] [Indexed: 12/31/2022]
Abstract
Holoprosencephaly (HPE), the most common forebrain malformation, is characterized by an incomplete separation of the cerebral hemispheres. Mutations in the homeobox gene SIX3 account for 1.3% of all cases of human HPE. Using zebrafish-based assays, we have now determined that HPE-associated Six3 mutant proteins function as hypomorphs. Haploinsufficiency of Six3 caused by deletion of one allele of Six3 or by replacement of wild-type Six3 with HPE-associated Six3 mutant alleles was sufficient to recapitulate in mouse models most of the phenotypic features of human HPE. We demonstrate that Shh is a direct target of Six3 in the rostral diencephalon ventral midline (RDVM). Reduced amounts of functional Six3 protein fail to activate Shh expression in the mutant RDVM and ultimately lead to HPE. These results identify Six3 as a direct regulator of Shh expression and reveal a crossregulatory loop between Shh and Six3 in the ventral forebrain.
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Affiliation(s)
- Xin Geng
- Department of Genetics and Tumor Cell Biology, St. Jude Children’s Research Hospital, Memphis, Tennessee 38105-2794, USA
| | - Christina Speirs
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee 37235-1634, USA
| | - Oleg Lagutin
- Department of Genetics and Tumor Cell Biology, St. Jude Children’s Research Hospital, Memphis, Tennessee 38105-2794, USA
| | - Adi Inbal
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee 37235-1634, USA
| | - Wei Liu
- Department of Genetics and Tumor Cell Biology, St. Jude Children’s Research Hospital, Memphis, Tennessee 38105-2794, USA
| | - Lilianna Solnica-Krezel
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee 37235-1634, USA
| | - Yongsu Jeong
- Department of Genetics, University of Pennsylvania, School of Medicine, Clinical Research Bldg., Philadelphia, PA 19104, USA
| | - Douglas Epstein
- Department of Genetics, University of Pennsylvania, School of Medicine, Clinical Research Bldg., Philadelphia, PA 19104, USA
| | - Guillermo Oliver
- Department of Genetics and Tumor Cell Biology, St. Jude Children’s Research Hospital, Memphis, Tennessee 38105-2794, USA
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22
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Abstract
Holoprosencephaly (HPE), characterized by incomplete separation of forebrain and facial components into left and right sides, is a common developmental defect in humans. It is caused by both genetic and environmental factors and its severity covers a wide spectrum of phenotypes. The genetic interactions underlying inherited forms of HPE are complex and poorly understood. Animal models, in particular mouse mutants, are providing a growing understanding of how the forebrain develops and how the cerebral hemispheres become split into left and right sides. These insights, along with the characterization to date of some of the genes involved in human HPE, suggest that two distinct mechanisms underlie the major classes of HPE, 'classic' and midline interhemispheric (MIH). Disruption either directly or indirectly of the ventralizing effect of sonic hedgehog signaling appears central to all or most forms of classic HPE, while disruption of the dorsalizing effect of bone morphogenetic protein signaling may be key to cases of MIH HPE.
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Affiliation(s)
- M Fernandes
- Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY 10461, USA
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23
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Lavado A, Lagutin OV, Oliver G. Six3 inactivation causes progressive caudalization and aberrant patterning of the mammalian diencephalon. Development 2008; 135:441-50. [PMID: 18094027 DOI: 10.1242/dev.010082] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2023]
Abstract
The homeobox gene Six3 represses Wnt1 transcription. It is also required in the anterior neural plate for the development of the mammalian rostral forebrain. We have now determined that at the 15- to 17-somite stage, the prospective diencephalon is the most-anterior structure in the Six3-null brain, and Wnt1 expression is anteriorly expanded. Consequently, the brain caudalizes, and at the 22- to 24-somite stage, the prospective thalamic territory is the most-anterior structure. At around E11.0, the pretectum replaces this structure. Analysis of Six3;Wnt1 double-null mice revealed that Six3-mediated repression of Wnt1 is necessary for the formation of the rostral diencephalon and that Six3 activity is required for the formation of the telencephalon. These results provide insight into the mechanisms that establish anteroposterior identity in the developing mammalian brain.
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Affiliation(s)
- Alfonso Lavado
- Department of Genetics and Tumor Cell Biology, St Jude Children's Research Hospital, 332 N. Lauderdale, Memphis, TN 38105-2794, USA
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24
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Kaiser R, Posteguillo EG, Müller D, Just W. Exclusion of genes from the EYA-DACH-SIX-PAX pathway as candidates for Branchio-Oculo-Facial syndrome (BOFS). Am J Med Genet A 2007; 143A:2185-8. [PMID: 17676609 DOI: 10.1002/ajmg.a.31875] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- René Kaiser
- Institute of Human Genetics, University of Ulm, Ulm, Germany
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