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Montaguti E, Cariello L, Brunelli E, Youssef A, Livi A, Salsi G, Pilu G. Sonography of fetal holoprosencephaly: a guide to recognize the lesser varieties. J Matern Fetal Neonatal Med 2022; 35:9717-9723. [PMID: 35272544 DOI: 10.1080/14767058.2022.2050900] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
BACKGROUND Alobar holoprosencephaly (HPE) is easily detected during a first-trimester screening examination, conversely, recognizing the lesser varieties may be difficult even in the second trimester. OBJECTIVES To describe the imaging findings of a cohort of fetuses with holoprosencephaly (HPE) and to elucidate the appearances of the different anatomical varieties. MATERIALS AND METHODS We reviewed medical records and stored images of pregnant women referred to our clinic because of a diagnosis or the suspicion of various forms of HPE. We reported the imaging characteristics, the presence of other associated anomalies, magnetic resonance findings, karyotype and autoptic examinations when available. RESULTS Alobar forms show great distortion of normal brain anatomy, with a single ventricle detectable during the first trimester of pregnancy. Extracerebral, face and karyotype abnormalities are often associated. In semilobar and lobar forms the septum pellucidum is typically absent in axial planes, with fused frontal horns, while posterior fossa is often normal. At multiplanar neurosonogram, anomalies involving corpus callosum and cortex development can be detected. Face abnormalities are mild in lobar forms: receding forehead, various degrees of hypotelorism and the presence of a single central maxillary incisor are reported. CONCLUSIONS The alobar forms are detectable since the first trimester, with a peculiar single ventricle and extremely frequent extracerebral and karyotype abnormalities. The semilobar and lobar forms are more challenging and the diagnosis is easily missed in a mid-trimester screening exam unless a careful evaluation of both cavum septi pellucidi and frontal horns as well is conducted.
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Affiliation(s)
- Elisa Montaguti
- Obstetric Unit, Department of Medical and Surgical Sciences, University of Bologna and IRCCS Azienda Ospedaliero-Universitaria S. Orsola-Malpighi, Bologna, Italy
| | - Luisa Cariello
- Obstetric Unit, Department of Medical and Surgical Sciences, University of Bologna and IRCCS Azienda Ospedaliero-Universitaria S. Orsola-Malpighi, Bologna, Italy
| | - Elena Brunelli
- Obstetric Unit, Department of Medical and Surgical Sciences, University of Bologna and IRCCS Azienda Ospedaliero-Universitaria S. Orsola-Malpighi, Bologna, Italy
| | - Aly Youssef
- Obstetric Unit, Department of Medical and Surgical Sciences, University of Bologna and IRCCS Azienda Ospedaliero-Universitaria S. Orsola-Malpighi, Bologna, Italy
| | - Alessandra Livi
- Obstetric Unit, Department of Medical and Surgical Sciences, University of Bologna and IRCCS Azienda Ospedaliero-Universitaria S. Orsola-Malpighi, Bologna, Italy
| | - Ginevra Salsi
- Obstetric Unit, Department of Medical and Surgical Sciences, University of Bologna and IRCCS Azienda Ospedaliero-Universitaria S. Orsola-Malpighi, Bologna, Italy
| | - Gianluigi Pilu
- Obstetric Unit, Department of Medical and Surgical Sciences, University of Bologna and IRCCS Azienda Ospedaliero-Universitaria S. Orsola-Malpighi, Bologna, Italy
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Albu CC, Albu DF, Pătraşcu A, Albu ŞD, Efrem IC, Gogănău AM. Prenatal diagnosis of syndromic alobar holoprosencephaly associated with digynic triploidy fetus. ROMANIAN JOURNAL OF MORPHOLOGY AND EMBRYOLOGY 2021; 61:1309-1316. [PMID: 34171079 PMCID: PMC8343603 DOI: 10.47162/rjme.61.4.32] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Holoprosencephaly (HPE) is a dramatic human brain malformation sequence with an extreme variable phenotypic spectrum and genetic heterogeneity, variable degree of severity and unknown etiology, in many cases. HPE is classified into syndromic, chromosomal, and non-syndromic, non-chromosomal. The most cases of HPE are syndromic. We present an atypical case of syndromic alobar HPE associated with digynic triploidy fetus, prenatally diagnosed, early at 18 weeks of gestation, by ultrasound (US) and complex genetic investigations. The US examination was performed with a specialized US machine, General Electric Voluson E10 OLED BT18, using two-dimensional (2D) scanning, three-dimensional (3D) image reconstruction, four-dimensional (4D) spatiotemporal image methodology and the highest power Doppler US technology. A detailed US examination of the fetus revealed several major abnormalities of the fetal head and severe facial malformations. Based on the antenatal US findings, the fetus was diagnosed with alobar HPE. After a careful examination and genetic counseling, additional cytogenetic investigations and molecular genetic analyses were performed, which revealed an abnormal number of 69 chromosomes, digynic triploidy (69,XXY). Two days later, the parents choose to interrupt the current gestation because of major fetal malformations. The pathological examination of the embryo reaffirmed the antenatal diagnostics.
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Affiliation(s)
- Cristina Crenguţa Albu
- Department of Genetics, Doctoral School, Carol Davila University of Medicine and Pharmacy, Bucharest, Romania; ,
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3
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Bosfield K, Diaz J, Leon E. Pure Distal 7q Duplication: Describing a Macrocephalic Neurodevelopmental Syndrome, Case Report and Review of the Literature. Mol Syndromol 2021; 12:159-168. [PMID: 34177432 DOI: 10.1159/000513453] [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: 08/27/2020] [Accepted: 11/28/2020] [Indexed: 11/19/2022] Open
Abstract
Pure distal duplications of 7q have rarely been described in the medical literature. The term pure refers to duplications that occur without an accompanying clinically significant deletion. Pure 7q duplications of various segments have previously been reported in the literature; however, pure distal 7q duplications have only been reported in 21 cases. Twenty of these earlier reports described patients who were identified via karyotype and 1 recently by microarray. Cases have also been reported in genomic databases such as DECIPHER and the University of California Santa Cruz genome browser. We have reviewed 7 additional cases with distal 7q duplications from these databases and compared them to 7 previously reported distal 7q duplication cases to uncover common features including global developmental delay, frontal bossing, macrocephaly, seizures, kyphoscoliosis/skeletal anomalies, and microretrognathia/palatal anomalies. In this case, we describe a 4-year-old boy with a 30.8-Mb pure duplication of 7q32.1q36.3. Newly reported features associated with this duplication include intermittent dystonic posturing, increased behavioral irritability, eosinophilic esophagitis, segmental vertebral anomalies, and segmental intermittent limb cyanosis. We highlight the importance of using publicly available databases to describe rare genetic syndromes and to better characterize the features of pure distal 7q duplications and further postulate that duplication of this region represents a recognizable macrocephalic neurodevelopmental syndrome.
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Affiliation(s)
- Kerri Bosfield
- Children's National Health System, Rare Disease Institute, Genetics and Metabolism, Washington, District of Columbia, USA
| | - Jullianne Diaz
- Children's National Health System, Rare Disease Institute, Genetics and Metabolism, Washington, District of Columbia, USA
| | - Eyby Leon
- Children's National Health System, Rare Disease Institute, Genetics and Metabolism, Washington, District of Columbia, USA
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5
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Abe Y, Araki R, Sobajima H, Tamura M, Kunikata T, Ohtake A, Yamanouchi H. Nationwide epidemiological survey of holoprosencephaly in Japan. Pediatr Int 2020; 62:593-599. [PMID: 31886593 DOI: 10.1111/ped.14135] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Revised: 10/02/2019] [Accepted: 12/25/2019] [Indexed: 11/28/2022]
Abstract
BACKGROUND Holoprosencephaly (HPE) is a congenital malformation with an estimated prevalence of 0.10-6.06 per 10 000 births but with no nationwide data specific to Japan. METHODS This nationwide retrospective questionnaire survey was conducted from 2011 to 2013. All 467 training hospitals for perinatal and neonatal care certified by the Japan Society of Perinatal and Neonatal Medicine were contacted. The birth prevalence rate (BPR) was assessed from the primary survey and clinical characteristics from the secondary survey. RESULTS We received valid responses from 253 hospitals in the primary survey (54.6%). Of 390 342 live births, 60 were diagnosed with HPE (23 males and 37 females), resulting in an actual BPR of 1.54 per 10 000 live births. The point estimate for HPE cases was 100 (95% confidence interval [CI]: 80.7-120), and the estimated BPR of HPE was calculated to be 0.32 per 10 000 live births (95% CI: 0.26-0.38) based on 3 117 853 live births according to Japanese national statistics during the study period. In the secondary survey, we obtained data for 49 cases (19 males and 30 females). Of these, 20 were alobar (40.8%), 20 were semilobar (40.8%), five were lobar (10.4%), and four were of unknown type. Genetic examination was performed in 37 of the 49 HPE patients and revealed that chromosomes 13, 18, and 7 were affected in eight, six, and four patients, respectively. CONCLUSIONS This is the most extensive survey on holoprosencephaly to date in Japan. The estimated BPR was consistent with that reported in previous research.
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Affiliation(s)
- Yuichi Abe
- Department of Pediatrics, Saitama Medical University, Saitama, Japan.,Division of Neurology, National Center for Child Health and Development, Tokyo, Japan
| | - Ryuichiro Araki
- Community Health Science Center, Saitama Medical University, Saitama, Japan
| | - Hisanori Sobajima
- Department of Pediatrics, Saitama Medical Center, Saitama Medical University, Saitama, Japan
| | - Masanori Tamura
- Department of Pediatrics, Saitama Medical Center, Saitama Medical University, Saitama, Japan
| | - Tetsuya Kunikata
- Department of Pediatrics, Saitama Medical University, Saitama, Japan
| | - Akira Ohtake
- Department of Pediatrics, Saitama Medical University, Saitama, Japan
| | - Hideo Yamanouchi
- Department of Pediatrics, Saitama Medical University, Saitama, Japan
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6
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Hu T, Kruszka P, Martinez AF, Ming JE, Shabason EK, Raam MS, Shaikh TH, Pineda-Alvarez DE, Muenke M. Cytogenetics and holoprosencephaly: A chromosomal microarray study of 222 individuals with holoprosencephaly. AMERICAN JOURNAL OF MEDICAL GENETICS PART C-SEMINARS IN MEDICAL GENETICS 2019; 178:175-186. [PMID: 30182442 DOI: 10.1002/ajmg.c.31622] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2018] [Revised: 04/18/2018] [Accepted: 04/20/2018] [Indexed: 11/08/2022]
Abstract
Holoprosencephaly (HPE), a common developmental forebrain malformation, is characterized by failure of the cerebrum to completely divide into left and right hemispheres. The etiology of HPE is heterogeneous and a number of environmental and genetic factors have been identified. Cytogenetically visible alterations occur in 25% to 45% of HPE patients and cytogenetic techniques have long been used to study copy number variants (CNVs) in this disorder. The karyotype approach initially demonstrated several recurrent chromosomal anomalies, which led to the identification of HPE-specific loci and, eventually, several major HPE genes. More recently, higher-resolution cytogenetic techniques such as subtelomeric multiplex ligation-dependent probe amplification and chromosomal microarray have been used to analyze chromosomal anomalies. By using chromosomal microarray, we sought to identify submicroscopic chromosomal deletions and duplications in patients with HPE. In an analysis of 222 individuals with HPE, a deletion or duplication was detected in 107 individuals. Of these 107 individuals, 23 (21%) had variants that were classified as pathogenic or likely pathogenic by board-certified medical geneticists. We identified multiple patients with deletions in established HPE loci as well as three patients with deletions encompassed by 6q12-q14.3, a CNV previously reported by Bendavid et al. In addition, we identified a new locus, 16p13.2 that warrants further investigation for HPE association. Incidentally, we also found a case of Potocki-Lupski syndrome, a case of Phelan-McDermid syndrome, and multiple cases of 22q11.2 deletion syndrome within our cohort. These data confirm the genetically heterogeneous nature of HPE, and also demonstrate clinical utility of chromosomal microarray in diagnosing patients affected by HPE.
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Affiliation(s)
- Tommy Hu
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland
| | - Paul Kruszka
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland
| | - Ariel F Martinez
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland
| | - Jeffrey E Ming
- Division of Human Genetics, The Children's Hospital of Philadelphia, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania
| | - Emily K Shabason
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland.,Division of Developmental and Behavioral Pediatrics, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Manu S Raam
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland.,General Pediatrics Services Shriners for Children Medical Center, Pasadena, California.,General Pediatrics Services Children's Hospital Los Angeles, Los Angeles, California
| | - Tamim H Shaikh
- Department of Pediatrics, University of Colorado School of Medicine, Aurora, Colorado.,Invitae Corporation, San Francisco, California
| | - Daniel E Pineda-Alvarez
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland.,Division of Developmental and Behavioral Pediatrics, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Maximilian Muenke
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland
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7
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Richieri-Costa A, Zechi-Ceide RM, Candido-Souza RM, Monteiro RAC, Tonello C, de Freitas ML, Kokitsu-Nakata NM, Vendramini-Pittoli S, Mazzeu JF, Overes M, Ali-Amin R, van Slegtenhorst M, Hoefsloot LH, Jehee FS. Holoprosencephaly, orofacial cleft, and frontonaso-orbital encephaloceles: Genetic evaluation of a possible new syndrome. Am J Med Genet A 2019; 179:2170-2177. [PMID: 31353810 DOI: 10.1002/ajmg.a.61305] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Revised: 06/18/2019] [Accepted: 07/09/2019] [Indexed: 11/06/2022]
Abstract
Here we report on a Brazilian child who presented semilobar holoprosencephaly, frontonasal encephaloceles and bilateral cleft lip and palate. Malformations also included agenesis of the corpus callosum, abnormal cortical gyres, dilation of the aqueduct, bilateral endolymphatic sac, bilateral cystic cocci-vestibular malformation, and a cribriform defect. The 3D TC craniofacial images showed abnormal frontonasal transition region, with a bone bifurcation, and partial agenesis of nasal bone. The trunk and upper and lower limbs were normal. To our knowledge, this rare association of holoprocensephaly with frontonaso-orbital encephaloceles without limb anomalies has never been reported before. Karyotype was normal. SNP-array showed no copy-number alterations but revealed 25% of regions of homozygosity (ROH) with normal copy number, indicating a high coefficient of inbreeding, which significantly increases the risk for an autosomal recessive disorder. Whole exome sequencing analysis did not reveal any pathogenic or likely pathogenic variants. We discuss the possible influence of two variants of uncertain significance found within the patient's ROHs. First, a missense p.(Gly394Ser) in PCSK9, a gene involved in the regulation of plasma low-density lipoprotein cholesterol. Second, an inframe duplication p.(Ala75_Ala81dup) in SP8, a zinc-finger transcription factor that regulates signaling centers during craniofacial development. Further studies and/or the identification of other patients with a similar phenotype will help elucidate the genetic etiology of this complex case.
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Affiliation(s)
- Antonio Richieri-Costa
- Department of Clinical Genetics, Hospital for Rehabilitation of Craniofacial Anomalies (HRCA), University of São Paulo, Bauru, São Paulo, Brazil
| | - Roseli M Zechi-Ceide
- Department of Clinical Genetics, Hospital for Rehabilitation of Craniofacial Anomalies (HRCA), University of São Paulo, Bauru, São Paulo, Brazil
| | - Rosana M Candido-Souza
- Department of Clinical Genetics, Hospital for Rehabilitation of Craniofacial Anomalies (HRCA), University of São Paulo, Bauru, São Paulo, Brazil
| | - Rejane A C Monteiro
- Institute of Education and Research, Santa Casa Belo Horizonte, Belo Horizonte, Minas Gerais, Brazil
| | - Cristiano Tonello
- Craniofacial Team Hospital for Rehabilitation of Craniofacial Anomalies (HRCA), University of São Paulo, Bauru, São Paulo, Brazil
| | - Mariana L de Freitas
- Institute of Education and Research, Santa Casa Belo Horizonte, Belo Horizonte, Minas Gerais, Brazil
| | - Nancy M Kokitsu-Nakata
- Department of Clinical Genetics, Hospital for Rehabilitation of Craniofacial Anomalies (HRCA), University of São Paulo, Bauru, São Paulo, Brazil
| | - Siulan Vendramini-Pittoli
- Department of Clinical Genetics, Hospital for Rehabilitation of Craniofacial Anomalies (HRCA), University of São Paulo, Bauru, São Paulo, Brazil
| | - Juliana F Mazzeu
- Faculty of Medicine, University of Brasília, Brasília, Distrito Federal, Brazil
| | - Madelief Overes
- Department of Clinical Genetics, Erasmus MC, Rotterdam, CN, The Netherlands
| | - Roza Ali-Amin
- Department of Clinical Genetics, Erasmus MC, Rotterdam, CN, The Netherlands
| | | | - Lies H Hoefsloot
- Department of Clinical Genetics, Erasmus MC, Rotterdam, CN, The Netherlands
| | - Fernanda S Jehee
- Institute of Education and Research, Santa Casa Belo Horizonte, Belo Horizonte, Minas Gerais, Brazil.,Department of Clinical Genetics, Erasmus MC, Rotterdam, CN, The Netherlands
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Dubourg C, Kim A, Watrin E, de Tayrac M, Odent S, David V, Dupé V. Recent advances in understanding inheritance of holoprosencephaly. AMERICAN JOURNAL OF MEDICAL GENETICS PART C-SEMINARS IN MEDICAL GENETICS 2018; 178:258-269. [PMID: 29785796 DOI: 10.1002/ajmg.c.31619] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2018] [Revised: 04/13/2018] [Accepted: 04/16/2018] [Indexed: 12/16/2022]
Abstract
Holoprosencephaly (HPE) is a complex genetic disorder of the developing forebrain characterized by high phenotypic and genetic heterogeneity. HPE was initially defined as an autosomal dominant disease, but recent research has shown that its mode of transmission is more complex. The past decade has witnessed rapid development of novel genetic technologies and significant progresses in clinical studies of HPE. In this review, we recapitulate genetic epidemiological studies of the largest European HPE cohort and summarize the novel genetic discoveries of HPE based on recently developed diagnostic methods. Our main purpose is to present different inheritance patterns that exist for HPE with a particular emphasis on oligogenic inheritance and its implications in genetic counseling.
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Affiliation(s)
- Christèle Dubourg
- Univ Rennes, CNRS, IGDR (Institut de génétique et développement de Rennes) - UMR 6290, F - 35000, Rennes, France.,Service de Génétique Moléculaire et Génomique, CHU, Rennes, France
| | - Artem Kim
- Univ Rennes, CNRS, IGDR (Institut de génétique et développement de Rennes) - UMR 6290, F - 35000, Rennes, France
| | - Erwan Watrin
- Univ Rennes, CNRS, IGDR (Institut de génétique et développement de Rennes) - UMR 6290, F - 35000, Rennes, France
| | - Marie de Tayrac
- Univ Rennes, CNRS, IGDR (Institut de génétique et développement de Rennes) - UMR 6290, F - 35000, Rennes, France.,Service de Génétique Moléculaire et Génomique, CHU, Rennes, France
| | - Sylvie Odent
- Univ Rennes, CNRS, IGDR (Institut de génétique et développement de Rennes) - UMR 6290, F - 35000, Rennes, France.,Service de Génétique Clinique, CHU, Rennes, France
| | - Véronique David
- Univ Rennes, CNRS, IGDR (Institut de génétique et développement de Rennes) - UMR 6290, F - 35000, Rennes, France.,Service de Génétique Moléculaire et Génomique, CHU, Rennes, France
| | - Valérie Dupé
- Univ Rennes, CNRS, IGDR (Institut de génétique et développement de Rennes) - UMR 6290, F - 35000, Rennes, France
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9
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Developmental neurogenesis in mouse and Xenopus is impaired in the absence of Nosip. Dev Biol 2017; 429:200-212. [DOI: 10.1016/j.ydbio.2017.06.026] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Revised: 06/23/2017] [Accepted: 06/23/2017] [Indexed: 01/01/2023]
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10
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Weiss K, Kruszka P, Guillen Sacoto MJ, Addissie YA, Hadley DW, Hadsall CK, Stokes B, Hu P, Roessler E, Solomon B, Wiggs E, Thurm A, Hufnagel RB, Zein WM, Hahn JS, Stashinko E, Levey E, Baldwin D, Clegg NJ, Delgado MR, Muenke M. In-depth investigations of adolescents and adults with holoprosencephaly identify unique characteristics. Genet Med 2017. [PMID: 28640243 PMCID: PMC5763157 DOI: 10.1038/gim.2017.68] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Purpose With improved medical care, some individuals with holoprosencephaly (HPE) are surviving into adulthood. We investigated the clinical manifestations of adolescents and adults with HPE and explored the underlying molecular causes. Methods Participants included 20 subjects 15 years of age and older. Clinical assessments included dysmorphology exams, cognitive testing, swallowing studies, ophthalmic examination, and brain magnetic resonance imaging. Genetic testing included chromosomal microarray, Sanger sequencing for SHH, ZIC2, SIX3, and TGIF, and whole-exome sequencing (WES) of 10 trios. Results Semilobar HPE was the most common subtype of HPE, seen in 50% of the participants. Neurodevelopmental disabilities were found to correlate with HPE subtype. Factors associated with long-term survival included HPE subtype not alobar, female gender, and nontypical facial features. Four participants had de novo pathogenic variants in ZIC2. WES analysis of 11 participants did not reveal plausible candidate genes, suggesting complex inheritance in these cases. Indeed, in two probands there was a history of uncontrolled maternal type 1 diabetes. Conclusion Individuals with various HPE subtypes can survive into adulthood and the neurodevelopmental outcomes are variable. Based on the facial characteristics and molecular evaluations, we suggest that classic genetic causes of HPE may play a smaller role in this cohort.
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Affiliation(s)
- Karin Weiss
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Paul Kruszka
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Maria J Guillen Sacoto
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Yonit A Addissie
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Donald W Hadley
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Casey K Hadsall
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Bethany Stokes
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Ping Hu
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Erich Roessler
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Beth Solomon
- Speech and Language Pathology Section, Department of Rehabilitation Medicine, Clinical Center, National Institutes of Health, Bethesda, Maryland, USA
| | - Edythe Wiggs
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, USA
| | - Audrey Thurm
- Pediatrics and Developmental Neuroscience Branch, National Institute of Mental Health, Bethesda, Maryland, USA
| | - Robert B Hufnagel
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Wadih M Zein
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Jin S Hahn
- Stanford University School of Medicine and Lucile Packard Children's Hospital, Stanford, California, USA
| | - Elaine Stashinko
- Neurology and Developmental Medicine, Kennedy Krieger Institute, Baltimore, Maryland, USA
| | - Eric Levey
- Neurology and Developmental Medicine, Kennedy Krieger Institute, Baltimore, Maryland, USA
| | - Debbie Baldwin
- Department of Neurology, Texas Scottish Rite Hospital for Children, Dallas, Texas, USA
| | - Nancy J Clegg
- Department of Neurology, Texas Scottish Rite Hospital for Children, Dallas, Texas, USA
| | - Mauricio R Delgado
- Department of Neurology, Texas Scottish Rite Hospital for Children, Dallas, Texas, USA.,Neurology and Neurotherapeutics, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas, USA
| | - Maximilian Muenke
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, USA
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11
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Wong K, Moldrich R, Hunter M, Edwards M, Finlay D, O'Donnell S, MacDougall T, Bain N, Kamien B. A familial 7q36.3 duplication associated with agenesis of the corpus callosum. Am J Med Genet A 2015; 167A:2201-8. [DOI: 10.1002/ajmg.a.37143] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Accepted: 04/19/2015] [Indexed: 11/09/2022]
Affiliation(s)
- Keith Wong
- The University of Newcastle; School of Medicine and Public Health; Newcastle New South Wales Australia
| | - Randal Moldrich
- The University of Queensland; The UQ Centre for Clinical Research; Brisbane Queensland Australia
| | - Matthew Hunter
- The University of Newcastle; School of Medicine and Public Health; Newcastle New South Wales Australia
- Hunter Genetics; Newcastle New South Wales Australia
| | - Matthew Edwards
- Paediatrics, School of Medicine; University of Western Sydney; Sydney New South Wales Australia
| | - David Finlay
- Faculty of Science, Technology, and Engineering; LaTrobe University; Bundoora Victoria Australia
| | | | - Tom MacDougall
- Department of Radiology; John Hunter Hospital; Newcastle New South Wales Australia
| | - Nicole Bain
- Hunter Area Pathology Service (HAPS); John Hunter Hospital; Newcastle New South Wales Australia
| | - Benjamin Kamien
- The University of Newcastle; School of Medicine and Public Health; Newcastle New South Wales Australia
- Hunter Genetics; Newcastle New South Wales Australia
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12
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Petryk A, Graf D, Marcucio R. Holoprosencephaly: signaling interactions between the brain and the face, the environment and the genes, and the phenotypic variability in animal models and humans. WILEY INTERDISCIPLINARY REVIEWS-DEVELOPMENTAL BIOLOGY 2014; 4:17-32. [PMID: 25339593 DOI: 10.1002/wdev.161] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2014] [Revised: 09/08/2014] [Accepted: 09/19/2014] [Indexed: 01/17/2023]
Abstract
Holoprosencephaly (HPE) is the most common developmental defect of the forebrain characterized by inadequate or absent midline division of the forebrain into cerebral hemispheres, with concomitant midline facial defects in the majority of cases. Understanding the pathogenesis of HPE requires knowledge of the relationship between the developing brain and the facial structures during embryogenesis. A number of signaling pathways control and coordinate the development of the brain and face, including Sonic hedgehog, Bone morphogenetic protein, Fibroblast growth factor, and Nodal signaling. Mutations in these pathways have been identified in animal models of HPE and human patients. Because of incomplete penetrance and variable expressivity of HPE, patients carrying defined mutations may not manifest the disease at all, or have a spectrum of defects. It is currently unknown what drives manifestation of HPE in genetically at-risk individuals, but it has been speculated that other gene mutations and environmental factors may combine as cumulative insults. HPE can be diagnosed in utero by a high-resolution prenatal ultrasound or a fetal magnetic resonance imaging, sometimes in combination with molecular testing from chorionic villi or amniotic fluid sampling. Currently, there are no effective preventive methods for HPE. Better understanding of the mechanisms of gene-environment interactions in HPE would provide avenues for such interventions.
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Affiliation(s)
- Anna Petryk
- Department of Pediatrics, University of Minnesota, Minneapolis, MN, USA
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Dicentric Chromosome 14;18 Plus Two Additional CNVs in a Girl with Microform Holoprosencephaly and Turner Stigmata. Balkan J Med Genet 2014; 16:67-72. [PMID: 24778566 PMCID: PMC4001418 DOI: 10.2478/bjmg-2013-0034] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
We report a 20-year-old female with features evocative of Turner syndrome (short stature, broad trunk, mild webbed neck), dysmorphic face, minor features of holo-prosencephaly (HPE), small hands and feet, excessive hair growth on anterior trunk and intellectual disability. Cytogenetic analysis identified a pseudodicentric 14;18 chromosome. Genome wide single nucleotide polymorphism (SNP) array showed a terminal deletion of approximately 10.24 Mb, from 18p11.32 to 18p11.22, flanked by a duplication of approximately 1.15 Mb, from 18p11.22 to 18p11.21. In addition, the SNP array revealed a duplication of 516 kb in 16p11.2. We correlated the patient’s clinical findings with the features mentioned in the literature for these copy number variations. This case study shows the importance of microarray analysis in the detection of cryptic chromosomal rearrangements in patients with intellectual disability and multiple congenital anomalies.
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Savastano CP, El-Jaick KB, Costa-Lima MA, Abath CMB, Bianca S, Cavalcanti DP, Félix TM, Scarano G, Llerena JC, Vargas FR, Moreira MÂM, Seuánez HN, Castilla EE, Orioli IM. Molecular analysis of holoprosencephaly in South America. Genet Mol Biol 2014; 37:250-62. [PMID: 24764759 PMCID: PMC3983586 DOI: 10.1590/s1415-47572014000200011] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Holoprosencephaly (HPE) is a spectrum of brain and facial malformations primarily reflecting genetic factors, such as chromosomal abnormalities and gene mutations. Here, we present a clinical and molecular analysis of 195 probands with HPE or microforms; approximately 72% of the patients were derived from the Latin American Collaborative Study of Congenital Malformations (ECLAMC), and 82% of the patients were newborns. Alobar HPE was the predominant brain defect in almost all facial defect categories, except for patients without oral cleft and median or lateral oral clefts. Ethmocephaly, cebocephaly, and premaxillary agenesis were primarily observed among female patients. Premaxillary agenesis occurred in six of the nine diabetic mothers. Recurrence of HPE or microform was approximately 19%. The frequency of microdeletions, detected using Multiplex Ligation-dependant Probe Amplification (MLPA) was 17% in patients with a normal karyotype. Cytogenetics or QF-PCR analyses revealed chromosomal anomalies in 27% of the probands. Mutational analyses in genes SHH, ZIC2, SIX3 and TGIF were performed in 119 patients, revealing eight mutations in SHH, two mutations in SIX3 and two mutations in ZIC2. Thus, a detailed clinical description of new HPE cases with identified genetic anomalies might establish genotypic and phenotypic correlations and contribute to the development of additional strategies for the analysis of new cases.
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Affiliation(s)
- Clarice Pagani Savastano
- Estudo Colaborativo Latino Americano de Malformações Congênitas, Departamento de Genética, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil . ; Instituto Nacional de Genética Médica Populacional, Rio de Janeiro, RJ, Brazil
| | - Kênia Balbi El-Jaick
- Departamento de Genética e Biologia Molecular, Universidade Federal do Estado do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | | | | | - Sebastiano Bianca
- Centro di Consulenza Genetica e di Teratologia della Riproduzione, Dipartimento Materno Infantile, ARNAS Garibaldi Nesima, Catania, CT, Italy
| | | | - Têmis Maria Félix
- Serviço de Genética Médica, Hospital das Clínicas de Porto Alegre, Porto Alegre, RS, Brazil
| | - Gioacchino Scarano
- Registro Campano Difetti Congeniti, Azienda Ospedaliera "Gaetano Rummo", Benevento, BN, Italy
| | - Juan Clinton Llerena
- Centro de Genética Médica, Instituto Fernandes Figueira, Fundação Oswaldo Cruz, Rio de Janeiro, RJ, Brazil
| | - Fernando Regla Vargas
- Departamento de Genética e Biologia Molecular, Universidade Federal do Estado do Rio de Janeiro, Rio de Janeiro, RJ, Brazil . ; Estudo Colaborativo Latino Americano de Malformações Congênitas, Laboratório de Epidemiologia de Defeitos Congênitos, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro, RJ, Brazil
| | | | - Hector N Seuánez
- Programa de Genética, Instituto Nacional de Câncer, Rio de Janeiro, RJ, Brazil
| | - Eduardo Enrique Castilla
- Instituto Nacional de Genética Médica Populacional, Rio de Janeiro, RJ, Brazil . ; Estudio Colaborativo Latino Americano de Malformaciones Congenitas, Centro de Educación Médica e Investigación Clínica, Buenos Aires, Argentina
| | - Iêda Maria Orioli
- Estudo Colaborativo Latino Americano de Malformações Congênitas, Departamento de Genética, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil . ; Instituto Nacional de Genética Médica Populacional, Rio de Janeiro, RJ, Brazil
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Lindsay CR, Roth DB. An unbiased method for detection of genome-wide off-target effects in cell lines treated with zinc finger nucleases. Methods Mol Biol 2014; 1114:353-69. [PMID: 24557915 DOI: 10.1007/978-1-62703-761-7_23] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
We describe a method for detecting and validating genomic aberrations arising from cell lines exposed to zinc finger nucleases (ZFNs), an important reagent used for targeted genome modifications. This method makes use of cloned cell lines, an approach that adds power when testing variables that may affect gene correction efficiency and evaluating potential side effects on a genome-wide scale. After cell treatment, the genomic DNA isolation method, as described, is ideal for high-resolution array comparative genomic hybridization (aCGH) and quantitative PCR. Guidelines for aCGH analysis and calling significant copy number variations (CNVs) for validation by qPCR are also discussed. Using this method, we describe a novel ZFN-associated chromosome 4 copy number variation (CNV) attributable to a predicted ZFN off-target cleavage site found within the CNV.
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Affiliation(s)
- Cory R Lindsay
- Department of Pathology and Laboratory Medicine, Raymond and Ruth Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
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Abstract
Brain malformations, particularly related to early brain development, are a clinically and genetically heterogeneous group of fetal neurological disorders. Fetal cerebral malformation, predominantly of impaired prosencephalic development namely agenesis of the corpus callosum and septo-optic dysplasia, is the main pathological feature in fetus, and causes prominent neurodevelopmental retardation, and associated with congenital facial anomalies and visual disorders. Differential diagnosis of brain malformations can be extremely difficult even through magnetic resonance imaging. Advances in genomic and molecular genetics technologies have led to the identification of the sonic hedgehog pathways and genes critical to the normal brain development. Molecular cytogenetic and genetic studies have identified numeric and structural chromosomal abnormalities as well as mutations in genes important for the etiology of fetal neurological disorders. In this review, we update the molecular genetics findings of three common fetal neurological abnormalities, holoprosencephaly, lissencephaly and agenesis of the corpus callosum, in an attempt to assist in perinatal and prenatal diagnosis.
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Affiliation(s)
- Jin Huang
- Fetal Medicine Unit, Department of Obstetrics and Gynaecology, The Chinese University of Hong Kong, Prince of Wales Hospital, Hong Kong SAR
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Ribeiro LA, Roessler E, Hu P, Pineda-Alvarez DE, Zhou N, Jones M, Chandrasekharappa S, Richieri-Costa A, Muenke M. Comparison of mutation findings in ZIC2 between microform and classical holoprosencephaly in a Brazilian cohort. ACTA ACUST UNITED AC 2012; 94:912-7. [PMID: 22847929 DOI: 10.1002/bdra.23047] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2012] [Revised: 05/10/2012] [Accepted: 05/23/2012] [Indexed: 01/05/2023]
Abstract
BACKGROUND Holoprosencephaly is the most frequent congenital malformation of the forebrain in humans. It is anatomically classified by the relative degree of abnormal formation and separation of the developing central nervous system. Mutations of ZIC2 are the second most common heterozygous variations detected in holoprosencephaly (HPE) patients. Mutations in most known HPE genes typically result in variable phenotypes that rage from classic alobar HPE to microforms represented by hypotelorism, solitary central maxillary incisor (SCMI), and cleft lip/palate, among others. Patients with HPE owing to ZIC2 mutations have recently been described by a distinct phenotype compared with mutations in other HPE causative genes. METHODS We report the comparison of ZIC2 molecular findings by Sanger bidirectional DNA sequencing and ad hoc genotyping in a cohort of 105 Brazilian patients within the clinical spectrum of HPE, including classic and microform groups. RESULTS We detected a total of five variants in the ZIC2 gene: a common histidine tract expansion c.716_718dup (p.His239dup), a rare c.1377_1391del_homozygous (p.Ala466_470del, or Ala 15 to 10 contraction), a novel intronic c.1239+18G>A variant, a novel frameshift c.1215dupC (p.Ser406Glnfs*11), and a c.1401_1406dup (p.Ala469_470dup, or alanine tract expansion to 17 residues). CONCLUSIONS From these patients, only the latter two mutations found in classic HPE are likely to be medically significant. In contrast, variants detected in the microform group are not likely to be pathogenic. We show conclusively that the histidine tract expansion is a polymorphic alteration that demonstrates considerable differences in allele frequencies across different ethnic groups. Therefore, careful population studies of rare variants can improve genotype-phenotype correlations. Birth Defects Research (Part A) 2012.
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Affiliation(s)
- Lucilene A Ribeiro
- Molecular Genetics Laboratory and Clinical Genetics Service, Hospital for Rehabilitation and Craniofacial Anomalies, University of Sao Paolo, Bauru, Sao Paolo, Brazil
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Roessler E, Vélez JI, Zhou N, Muenke M. Utilizing prospective sequence analysis of SHH, ZIC2, SIX3 and TGIF in holoprosencephaly probands to describe the parameters limiting the observed frequency of mutant gene×gene interactions. Mol Genet Metab 2012; 105:658-64. [PMID: 22310223 PMCID: PMC3309119 DOI: 10.1016/j.ymgme.2012.01.005] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/06/2011] [Revised: 01/05/2012] [Accepted: 01/05/2012] [Indexed: 11/29/2022]
Abstract
Clinical molecular diagnostic centers routinely screen SHH, ZIC2, SIX3 and TGIF for mutations that can help to explain holoprosencephaly and related brain malformations. Here we report a prospective Sanger sequence analysis of 189 unrelated probands referred to our diagnostic lab for genetic testing. We identified 28 novel unique mutations in this group (15%) and no instances of deleterious mutations in two genes in the same subject. Our result extends that of other diagnostic centers and suggests that among the aggregate 475 prospectively sequenced holoprosencephaly probands there is negligible evidence for direct gene-gene interactions among these tested genes. We model the predictions of the observed mutation frequency in the context of the hypothesis that gene×gene interactions are a prerequisite for forebrain malformations, i.e. the "multiple-hit" hypothesis. We conclude that such a direct interaction would be expected to be rare and that more subtle genetic and environmental interactions are a better explanation for the clinically observed inter- and intra-familial variability.
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Affiliation(s)
- Erich Roessler
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - Jorge I. Vélez
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - Nan Zhou
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - Maximilian Muenke
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
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Vaz SS, Chodirker B, Prasad C, Seabrook JA, Chudley AE, Prasad AN. Risk factors for nonsyndromic holoprosencephaly: a Manitoba case-control study. Am J Med Genet A 2012; 158A:751-8. [PMID: 22419615 DOI: 10.1002/ajmg.a.35240] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2011] [Accepted: 12/27/2011] [Indexed: 12/08/2022]
Abstract
Holoprosencephaly (HPE) is one of the most common developmental field defects, occurring in 1 in 250 conceptuses and in 1 in 10,000-20,000 live births. Nearly half of patients with HPE have a recognized syndrome or a single gene defect. However, little is known about the risk factors for the remainder with "nonsyndromic" HPE. In our case-control study, we examine factors associated with nonsyndromic HPE. We identified 47 patients with HPE from the genetics clinic database with an equal number of controls matched for gender and birthdate. Of the 47 patients, 23 were identified as nonsyndromic. No statistically significant differences were noted between the mean maternal and paternal ages of patients and controls. Factors associated with nonsyndromic HPE were: having an Aboriginal mother (unadjusted odds ratio [OR] 3.5, 95% confidence interval [CI] 1.1-11.1), an Aboriginal father (OR 12.8, 95% CI 3.0-55.1), at least one Aboriginal parent (OR 5.0, 95% CI 1.6-16.0), or two Aboriginal parents (OR 8.8, 95% CI 2.0-37.8), the presence of a family history of a midline facial defect (OR 8.2, 95% CI 1.5-45.2), and being of low socioeconomic status (OR 3.0, 95% CI 1.0-9.1). Having an Aboriginal background remained statistically significant after adjusting for low socioeconomic status. Other associations evaluated--history of prior spontaneous abortion, stillbirth, neonatal death, prepregnancy diabetes, infections during pregnancy, alcohol exposure, smoking, and substance abuse--were not significantly associated with nonsyndromic HPE. The use of periconceptional folic acid or vitamins was not associated with a lower risk of nonsyndromic HPE.
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Affiliation(s)
- Simone S Vaz
- Department of Pediatrics, William Osler Health System, Brampton, Ontario, Canada
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Delahaye A, Bitoun P, Drunat S, Gérard-Blanluet M, Chassaing N, Toutain A, Verloes A, Gatelais F, Legendre M, Faivre L, Passemard S, Aboura A, Kaltenbach S, Quentin S, Dupont C, Tabet AC, Amselem S, Elion J, Gressens P, Pipiras E, Benzacken B. Genomic imbalances detected by array-CGH in patients with syndromal ocular developmental anomalies. Eur J Hum Genet 2012; 20:527-33. [PMID: 22234157 DOI: 10.1038/ejhg.2011.233] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
In 65 patients, who had unexplained ocular developmental anomalies (ODAs) with at least one other birth defect and/or intellectual disability, we performed oligonucleotide comparative genome hybridisation-based microarray analysis (array-CGH; 105A or 180K, Agilent Technologies). In four patients, array-CGH identified clinically relevant deletions encompassing a gene known to be involved in ocular development (FOXC1 or OTX2). In four other patients, we found three pathogenic deletions not classically associated with abnormal ocular morphogenesis, namely, del(17)(p13.3p13.3), del(10)(p14p15.3), and del(16)(p11.2p11.2). We also detected copy number variations of uncertain pathogenicity in two other patients. Rearranged segments ranged in size from 0.04 to 5.68 Mb. These results show that array-CGH provides a high diagnostic yield (15%) in patients with syndromal ODAs and can identify previously unknown chromosomal regions associated with these conditions. In addition to their importance for diagnosis and genetic counselling, these data may help identify genes involved in ocular development.
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Affiliation(s)
- Andrée Delahaye
- AP-HP, Hôpital Jean Verdier, Service d'Histologie, Embryologie, et Cytogénétique, Bondy, France.
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Kevelam SHG, van Harssel JJT, van der Zwaag B, Smeets HJM, Paulussen ADC, Lichtenbelt KD. A patient with a mild holoprosencephaly spectrum phenotype and heterotaxy and a 1.3 Mb deletion encompassing GLI2. Am J Med Genet A 2011; 158A:166-73. [PMID: 22106008 DOI: 10.1002/ajmg.a.34350] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2011] [Accepted: 09/04/2011] [Indexed: 11/12/2022]
Abstract
Loss-of-function mutations of GLI2 are associated with features at the mild end of the holoprosencephaly spectrum, including abnormal pituitary gland formation and/or function, and craniofacial abnormalities. In addition patients may have branchial arch anomalies and polydactyly. Large, microscopically visible, interstitial deletions spanning 2q14.2 have been reported in patients with multiple congenital anomalies and intellectual disability. We report here on a patient with a mild holoprosencephaly spectrum phenotype (bilateral cleft lip and palate and abnormal pituitary gland formation with panhypopituitarism) and normal psychomotor development, who was found to carry a 1.3 Mb submicroscopic heterozygous deletion in 2q14.2, encompassing the GLI2 gene. We review the genotype and phenotype of previously published probands with GLI2 aberrations. Our findings confirm the association of haploinsufficiency of GLI2 and mild HPE spectrum features. Consistent with prior reports, we observed incomplete penetrance of the deletion in the family, illustrating the multifactorial etiology of holoprosencephaly spectrum features. In addition to the holoprosencephaly spectrum features, the proband had heterotaxy of the abdominal organs. Mutations in the known heterotaxy genes (NODAL, ZIC3 and CFC1) were excluded. The deletion contains five genes, in addition to GLI2, including the EPB4.1l5 gene. Based on findings in Epb4.1l5 mutant mice we hypothesize that Epb4.1l5 is a candidate gene for the heterotaxy observed in the proband.
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Affiliation(s)
- Sietske H G Kevelam
- Department of Medical Genetics, University Medical Center Utrecht, Utrecht, The Netherlands.
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Mercier S, Dubourg C, Garcelon N, Campillo-Gimenez B, Gicquel I, Belleguic M, Ratié L, Pasquier L, Loget P, Bendavid C, Jaillard S, Rochard L, Quélin C, Dupé V, David V, Odent S. New findings for phenotype-genotype correlations in a large European series of holoprosencephaly cases. J Med Genet 2011; 48:752-60. [PMID: 21940735 PMCID: PMC3386902 DOI: 10.1136/jmedgenet-2011-100339] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
BACKGROUND Holoprosencephaly (HPE) is the most common forebrain defect in humans. It results from incomplete midline cleavage of the prosencephalon. METHODS A large European series of 645 HPE probands (and 699 relatives), consisting of 51% fetuses and 49% liveborn children, is reported. RESULTS Mutations in the four main genes involved in HPE (SHH, ZIC2, SIX3, TGIF) were identified in 25% of cases. The SHH, SIX3, and TGIF mutations were inherited in more than 70% of these cases, whereas 70% of the mutations in ZIC2 occurred de novo. Moreover, rearrangements were detected in 22% of the 260 patients screened by array comparative genomic hybridisation. 15 probands had two mutations providing additional support for the 'multiple-hit process' in HPE. There was a positive correlation between the severity of the brain malformation and facial features for SHH, SIX3, and TGIF, but no such correlation was found for ZIC2 mutations. The most severe HPE types were associated with SIX3 and ZIC2 mutations, whereas microforms were associated with SHH mutations. The study focused on the associated brain malformations, including neuronal migration defects, which predominated in individuals with ZIC2 mutations, and neural tube defects, which were frequently associated with ZIC2 (rachischisis) and TGIF mutations. Extracraniofacial features were observed in 27% of the individuals in this series (up to 40% of those with ZIC2 mutations) and a significant correlation was found between renal/urinary defects and mutations of SHH and ZIC2. CONCLUSIONS An algorithm is proposed based on these new phenotype-genotype correlations, to facilitate molecular analysis and genetic counselling for HPE.
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Affiliation(s)
- Sandra Mercier
- IGDR, Institut de Génétique et Développement de Rennes
CNRS : UMR6061Université de Rennes 1IFR140Faculté de Médecine - CS 34317 2 Av du Professeur Léon Bernard 35043 RENNES CEDEX,FR
- Service de génétique médicale
CHU RennesUniversité de Rennes 116 bd de Bulgarie BP 90437, 35203 Rennes Cedex 2,FR
| | - Christèle Dubourg
- IGDR, Institut de Génétique et Développement de Rennes
CNRS : UMR6061Université de Rennes 1IFR140Faculté de Médecine - CS 34317 2 Av du Professeur Léon Bernard 35043 RENNES CEDEX,FR
| | - Nicolas Garcelon
- LIM, Laboratoire d'Informatique Médicale
Université de Rennes 1Laboratoire d'Informatique Médicale CHU - Pontchaillou 2, rue Henri Le Guilloux 35033 RENNES,FR
| | - Boris Campillo-Gimenez
- LIM, Laboratoire d'Informatique Médicale
Université de Rennes 1Laboratoire d'Informatique Médicale CHU - Pontchaillou 2, rue Henri Le Guilloux 35033 RENNES,FR
| | - Isabelle Gicquel
- IGDR, Institut de Génétique et Développement de Rennes
CNRS : UMR6061Université de Rennes 1IFR140Faculté de Médecine - CS 34317 2 Av du Professeur Léon Bernard 35043 RENNES CEDEX,FR
| | - Marion Belleguic
- Service de génétique médicale
CHU RennesUniversité de Rennes 116 bd de Bulgarie BP 90437, 35203 Rennes Cedex 2,FR
| | - Leslie Ratié
- IGDR, Institut de Génétique et Développement de Rennes
CNRS : UMR6061Université de Rennes 1IFR140Faculté de Médecine - CS 34317 2 Av du Professeur Léon Bernard 35043 RENNES CEDEX,FR
| | - Laurent Pasquier
- Service de génétique médicale
CHU RennesUniversité de Rennes 116 bd de Bulgarie BP 90437, 35203 Rennes Cedex 2,FR
| | - Philippe Loget
- Service d'anatomie et cytologie pathologiques
Hôpital PontchaillouUniversité de Rennes 1CHU Rennes2, rue Henri-le-Guilloux, 35000 Rennes,FR
| | - Claude Bendavid
- IGDR, Institut de Génétique et Développement de Rennes
CNRS : UMR6061Université de Rennes 1IFR140Faculté de Médecine - CS 34317 2 Av du Professeur Léon Bernard 35043 RENNES CEDEX,FR
| | - Sylvie Jaillard
- IGDR, Institut de Génétique et Développement de Rennes
CNRS : UMR6061Université de Rennes 1IFR140Faculté de Médecine - CS 34317 2 Av du Professeur Léon Bernard 35043 RENNES CEDEX,FR
| | - Lucie Rochard
- IGDR, Institut de Génétique et Développement de Rennes
CNRS : UMR6061Université de Rennes 1IFR140Faculté de Médecine - CS 34317 2 Av du Professeur Léon Bernard 35043 RENNES CEDEX,FR
| | - Chloé Quélin
- Service de génétique médicale
CHU RennesUniversité de Rennes 116 bd de Bulgarie BP 90437, 35203 Rennes Cedex 2,FR
| | - Valérie Dupé
- IGDR, Institut de Génétique et Développement de Rennes
CNRS : UMR6061Université de Rennes 1IFR140Faculté de Médecine - CS 34317 2 Av du Professeur Léon Bernard 35043 RENNES CEDEX,FR
| | - Véronique David
- IGDR, Institut de Génétique et Développement de Rennes
CNRS : UMR6061Université de Rennes 1IFR140Faculté de Médecine - CS 34317 2 Av du Professeur Léon Bernard 35043 RENNES CEDEX,FR
| | - Sylvie Odent
- IGDR, Institut de Génétique et Développement de Rennes
CNRS : UMR6061Université de Rennes 1IFR140Faculté de Médecine - CS 34317 2 Av du Professeur Léon Bernard 35043 RENNES CEDEX,FR
- Service de génétique médicale
CHU RennesUniversité de Rennes 116 bd de Bulgarie BP 90437, 35203 Rennes Cedex 2,FR
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Marquis-Nicholson R, Aftimos S, Ashton F, Love JM, Stone P, McFarlane J, George AM, Love DR. Pseudotrisomy 13 syndrome: Use of homozygosity mapping to target candidate genes. Gene 2011; 486:37-40. [DOI: 10.1016/j.gene.2011.06.028] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2011] [Accepted: 06/24/2011] [Indexed: 12/01/2022]
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D'Amours G, Kibar Z, Mathonnet G, Fetni R, Tihy F, Désilets V, Nizard S, Michaud JL, Lemyre E. Whole-genome array CGH identifies pathogenic copy number variations in fetuses with major malformations and a normal karyotype. Clin Genet 2011; 81:128-41. [PMID: 21496010 DOI: 10.1111/j.1399-0004.2011.01687.x] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Despite a wide range of clinical tools, the etiology of mental retardation and multiple congenital malformations remains unknown for many patients. Array-based comparative genomic hybridization (aCGH) has proven to be a valuable tool in these cases, as its pangenomic coverage allows the identification of chromosomal aberrations that are undetectable by other genetic methods targeting specific genomic regions. Therefore, aCGH is increasingly used in clinical genetics, both in the postnatal and the prenatal settings. While the diagnostic yield in the postnatal population has been established at 10-12%, studies investigating fetuses have reported variable results. We used whole-genome aCGH to investigate fetuses presenting at least one major malformation detected on ultrasound, but for whom standard genetic analyses (including karyotype) failed to provide a diagnosis. We identified a clinically significant chromosomal aberration in 8.2% of tested fetuses (4/49), and a result of unclear clinical significance in 12.2% of tested fetuses (6/49). Our results document the value of whole-genome aCGH as a prenatal diagnostic tool and highlight the interpretation difficulties associated with copy number variations of unclear significance.
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Affiliation(s)
- G D'Amours
- Service de Génétique Médicale, CHU Sainte-Justine, Montréal, QC, Canada
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Bertolacini CDP, Ribeiro-Bicudo LA, Petrin A, Richieri-Costa A, Murray JC. Clinical findings in patients with GLI2 mutations--phenotypic variability. Clin Genet 2011; 81:70-5. [PMID: 21204792 DOI: 10.1111/j.1399-0004.2010.01606.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Mutations in the human GLI2 gene were first reported in association with defective anterior pituitary formation, panhypopituitarism, and forebrain anomalies represented by typical holoprosencephaly (HPE) and holoprosencephaly-like (HPE-L) phenotypes and postaxial polydactyly. Subsequently, anophthalmia plus orbital anomalies, heminasal aplasia, branchial arch anomalies and polydactyly have also been incorporated into the general phenotype. Here we described six Brazilian patients with phenotypic manifestations that range from isolated cleft lip/palate with polydactyly, branchial arch anomalies to semi-lobar holoprosencephaly. Novel sequence variants were found in the GLI2 gene in patients with marked involvement of the temporomandibular joint (TMJ), a new clinical finding observed with mutations of this gene. Clinical, molecular and genetic aspects are discussed.
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Affiliation(s)
- C D P Bertolacini
- Hospital of Rehabilitation of Craniofacial Anomalies, USP, Bauru, SP, Brazil
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Dupé V, Rochard L, Mercier S, Le Pétillon Y, Gicquel I, Bendavid C, Bourrouillou G, Kini U, Thauvin-Robinet C, Bohan TP, Odent S, Dubourg C, David V. NOTCH, a new signaling pathway implicated in holoprosencephaly. Hum Mol Genet 2010; 20:1122-31. [PMID: 21196490 DOI: 10.1093/hmg/ddq556] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Genetics of Holoprosencephaly (HPE), a congenital malformation of the developing human forebrain, is due to multiple genetic defects. Most genes that have been implicated in HPE belong to the sonic hedgehog signaling pathway. Here we describe a new candidate gene isolated from array comparative genomic hybridization redundant 6qter deletions, DELTA Like 1 (DLL1), which is a ligand of NOTCH. We show that DLL1 is co-expressed in the developing chick forebrain with Fgf8. By treating chick embryos with a pharmacological inhibitor, we demonstrate that DLL1 interacts with FGF signaling pathway. Moreover, a mutation analysis of DLL1 in HPE patients revealed a three-nucleotide deletion. These various findings implicate DLL1 in early patterning of the forebrain and identify NOTCH as a new signaling pathway involved in HPE.
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Affiliation(s)
- Valérie Dupé
- Institut de Génétique et Développement, CNRS UMR6061, Université de Rennes 1, IFR140 GFAS, Faculté de Médecine, Rennes, France
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27
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Bibliography. Genetics. Current world literature. Curr Opin Pediatr 2010; 22:833-5. [PMID: 21610333 DOI: 10.1097/mop.0b013e32834179f9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Abstract
PURPOSE OF REVIEW This review presents recent advances in our understanding and clinical management of holoprosencephaly (HPE). HPE is the most common developmental disorder of the human forebrain and involves incomplete or failed separation of the cerebral hemispheres. The epidemiology, clinical features, causes, diagnostic approach, management, and outcomes of HPE are discussed. RECENT FINDINGS Chromosomal abnormalities account for the most commonly identified cause of HPE. However, there are often unidentifiable causes in patients with nonsyndromic, nonchromosomal forms of HPE. The prevalence of HPE may be underestimated given that patients with mild forms often are not diagnosed until they present with severely affected children. Pregestational maternal diabetes mellitus is the most recognized risk factor for HPE, as supported by recent large-scale epidemiological studies. Genetic studies using microarray-based comparative genomic hybridization technology have resulted in better characterization of important HPE loci. SUMMARY HPE encompasses a wide spectrum of forebrain and midline defects, with an accompanying wide spectrum of clinical manifestations. A coordinated, multidisciplinary care team is required for clinical management of this complex disorder. Further research will enable us to better understand the pathogenesis and causes of HPE, and thus to improve the genetic counseling of patients and their families.
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Ribeiro LA, Quiezi RG, Nascimento A, Bertolacini CP, Richieri-Costa A. Holoprosencephaly and holoprosencephaly-like phenotype and GAS1 DNA sequence changes: Report of four Brazilian patients. Am J Med Genet A 2010; 152A:1688-94. [PMID: 20583177 DOI: 10.1002/ajmg.a.33466] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Holoprosencephaly (HPE) is genetically heterogeneous. Variable phenotypic manifestations within families with normal and affected patients have been attributed to the number and type of HPE gene mutations. Environmental agents may also contribute to the severity as well as the requirement of multiple hits. Clinical expression is extremely variable ranging from minor facial signs to complex craniofacial anomalies such as cyclopia. Main genes involved include SHH, GLI2, PTCH1, TGIF, ZIC2, TDGF1, SIX3; however, several other candidates have been proposed. Recently it was established that the human growth arrest specific gene 1 (GAS1) is a potential locus for several human craniofacial malformations. Here, we report on four Brazilian patients with GAS1 DNA sequence change who presented variable phenotypical manifestations ranging from classic HPE to HPE-like signs. Two patients had single DNA sequence change in the GAS1 gene, while in other two, an additional mutation in the SHH gene was observed. Clinical manifestations presented by these patients suggest that GAS1 could be considered a candidate locus for one of the types of human HPE.
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Affiliation(s)
- Lucilene Arilho Ribeiro
- Molecular Genetics Laboratory and Clinical Genetic Service, Hospital for Rehabilitation of Craniofacial Anomalies, USP, Bauru, SP, Brazil
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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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Johnson CY, Rasmussen SA. Non-genetic risk factors for holoprosencephaly. AMERICAN JOURNAL OF MEDICAL GENETICS PART C-SEMINARS IN MEDICAL GENETICS 2010; 154C:73-85. [PMID: 20104598 DOI: 10.1002/ajmg.c.30242] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Holoprosencephaly (HPE) is a congenital defect of the brain characterized by incomplete cleavage of the embryonic forebrain into left and right hemispheres. Although a substantial proportion of cases of HPE can be attributed to genetic abnormalities, the etiology in many cases remains unknown, with non-genetic risk factors believed to be important contributors. Due to the low birth prevalence of this defect, it has proven difficult to conduct studies of sufficient size to identify risk factors with certainty. This article provides a summary of non-genetic risk factors for HPE that have been investigated in case reports and case series, animal studies, and epidemiologic studies, including maternal illnesses, therapeutic and non-therapeutic exposures, nutritional factors, and sociodemographic factors. The article also highlights challenges in study design and further areas for research to better understand the etiology of HPE.
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Mercier S, Dubourg C, Belleguic M, Pasquier L, Loget P, Lucas J, Bendavid C, Odent S. Genetic counseling and "molecular" prenatal diagnosis of holoprosencephaly (HPE). AMERICAN JOURNAL OF MEDICAL GENETICS PART C-SEMINARS IN MEDICAL GENETICS 2010; 154C:191-6. [PMID: 20104616 DOI: 10.1002/ajmg.c.30246] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Holoprosencephaly (HPE) is a structural anomaly of the developing brain in which the forebrain fails to divide into two separate hemispheres and ventricles. The poor prognosis in the most severe forms justifies the importance of genetic counseling in affected families. The genetic counseling requires a thorough clinical approach given the extreme variability of phenotype and etiology. The karyotype is an essential diagnostic tool. Since mutations in the four major genes (SHH, ZIC2, SIX3, and TGIF) have been identified in HPE patients, molecular study is performed routinely in nonsyndromic HPE. New molecular tools, such as array-CGH analysis, are now part of the diagnostic process. Prenatal diagnosis is based primarily on fetal imaging, but "molecular" prenatal diagnosis can be performed if a mutation has been previously identified in a proband. Interpretations of molecular diagnosis must be given with caution, given the lack of strict genotype-phenotype correlation, and should be offered in addition to fetal imaging, using ultrasound followed by fetal MRI. We report on our experience of 15 molecular prenatal diagnoses from chorionic villi or amniotic fluid sampling. In eight instances, we were able to reassure the parents after taking into account the absence of the mutation in the fetus, previously identified before in a parent and/or a proband. Fetal RMI was normal later in pregnancy, and no child had medical problems after birth. The mutation was found in the seven other cases: four children were born, either without brain malformation and asymptomatic, or had a less severe form than the index case.
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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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Holoprosencephaly: An update on cytogenetic abnormalities. AMERICAN JOURNAL OF MEDICAL GENETICS PART C-SEMINARS IN MEDICAL GENETICS 2010; 154C:86-92. [DOI: 10.1002/ajmg.c.30250] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Pineda-Alvarez DE, Dubourg C, David V, Roessler E, Muenke M. Current recommendations for the molecular evaluation of newly diagnosed holoprosencephaly patients. AMERICAN JOURNAL OF MEDICAL GENETICS. PART C, SEMINARS IN MEDICAL GENETICS 2010; 154C:93-101. [PMID: 20104604 PMCID: PMC2815008 DOI: 10.1002/ajmg.c.30253] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Holoprosencephaly (HPE) is the most common structural malformation of the developing forebrain in humans and is typically characterized by different degrees of hemispheric separation that are often accompanied by similarly variable degrees of craniofacial and midline anomalies. HPE is a classic example of a complex genetic trait with "pseudo"-autosomal dominant transmission showing incomplete penetrance and variable expressivity. Clinical suspicion of HPE is typically based upon compatible craniofacial findings, the presence of developmental delay or seizures, or specific endocrinological abnormalities, and is then followed up by confirmation with brain imaging. Once a clinical diagnosis is made, a thorough genetic evaluation is necessary. This usually includes analysis of chromosomes by high-resolution karyotyping, clinical assessment to rule-out well recognized syndromes that are associated with HPE (e.g., Pallister-Hall syndrome, Smith-Lemli-Opitz syndrome and others), and molecular studies of the most common HPE associated genes (e.g., SHH, ZIC2 and SIX3). In this review, we provide current step-by-step recommendations that are medically indicated for the genetic evaluation of patients with newly diagnosed HPE. Moreover, we provide a brief review of several available methods used in molecular diagnostics of HPE and describe the advantages and limitations of both currently available and future tests as they relate to high throughput screening, cost, and the results that they may provide.
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Affiliation(s)
| | - Christèle Dubourg
- Université de Rennes 1, Faculté de Médecine - UMR 6061 CNRS, IFR140 GFAS, Rennes, France
- CHU Pontchaillou - Laboratoire de Génétique Moléculaire, Rennes, France
| | - Véronique David
- Université de Rennes, 35042 - CNRS Génétique et Développement, Rennes, France
| | - Erich Roessler
- National Human Genome Research Institute - Medical Genetics Branch, Bethesda, Maryland, USA
| | - Maximilian Muenke
- National Human Genome Research Institute - Medical Genetics Branch, Bethesda, Maryland, USA
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