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Huang J, Saint-Martin C, Tchakarska G, Lavoie J, Myers KA. Cerebral white matter abnormalities associated with chromosome 18q duplication. Brain Dev 2022; 44:562-566. [PMID: 35469635 DOI: 10.1016/j.braindev.2022.04.004] [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: 01/18/2022] [Revised: 03/18/2022] [Accepted: 04/10/2022] [Indexed: 10/18/2022]
Abstract
BACKGROUND Chromosome 18q duplications are associated with a range of phenotypes often similar to complete trisomy 18, variably including poor growth, feeding difficulties, congenital malformations and dysmorphic facial features. Although 18q duplication patients may have seizures and developmental impairment, brain MRI typically shows only variable degrees of cerebral atrophy. PATIENT We present a boy with a 52.2 Mb 18q duplication in whom brain MRI in the neonatal period showed striking white matter abnormalities, most notable in the frontal lobes. His clinical presentation was otherwise in keeping with trisomy 18, including characteristic facial features, hypotonia, cardiac malformation, rocker bottom feet, pectus excavatum, short and broad thumbs and halluces, and diabetes insipidus. CONCLUSION Since not previously reported in association with 18q duplication, the observation of cerebral white matter anomalies is particularly interesting. This radiologic pattern is a well-recognized feature of 18q deletion syndrome, hypothesized by many to occur due to haploinsufficiency of MBP, the gene encoding myelin basic protein. The mechanisms leading to the white matter anomalies in this patient remain unexplained.
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Affiliation(s)
- Jiayin Huang
- Faculty of Medicine and Health Sciences, McGill University, Montreal, Quebec, Canada
| | - Christine Saint-Martin
- Department of Medical Imaging, Montreal Children's Hospital, McGill University Health Centre, Montreal, Quebec, Canada
| | - Guergana Tchakarska
- McGill University Health Centre, Montreal, Quebec, Canada; Department of Human Genetics, McGill University, Montreal, Quebec, Canada
| | - Josée Lavoie
- Department of Human Genetics, McGill University, Montreal, Quebec, Canada; Department of Pathology, McGill University, Montreal, Quebec, Canada
| | - Kenneth A Myers
- Research Institute of the McGill University Medical Centre, Montreal, Quebec, Canada; Division of Neurology, Department of Pediatrics, Montreal Children's Hospital, McGill University Health Centre, Montreal, Quebec, Canada; Department of Neurology and Neurosurgery, McGill University Health Centre, Montreal, Quebec, Canada.
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Lammert DB, Miedema D, Ochotorena J, Dosa N, Petropoulou K, Lebel RR, Sakonju A. Central and peripheral dysmyelination in a 3-year-old girl with ring chromosome 18. Clin Case Rep 2019; 7:2087-2091. [PMID: 31788257 PMCID: PMC6878035 DOI: 10.1002/ccr3.2426] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2019] [Revised: 08/03/2019] [Accepted: 08/12/2019] [Indexed: 11/22/2022] Open
Abstract
Myelin basic protein (MBP) contributes to peripheral and central nervous system myelin. Developmental myelinopathies exist on a clinical spectrum, but MBP is not included on leukodystrophy or CMT gene panels. This ring chromosome 18 case presents serial MRI and EMG/NCS, shedding light on the early clinical course of the disorder.
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Affiliation(s)
- Dawn Brianna Lammert
- Department of PediatricsJohns Hopkins HospitalBaltimoreMaryland
- Present address:
Department of PediatricsJohns Hopkins HospitalBaltimoreMaryland
| | | | - Josiree Ochotorena
- Child and Adolescent Health AssociatesSamaritan Health SystemsWatertownNew York
| | - Nienke Dosa
- Center for Development, Behavior, and GeneticsSUNY Upstate Medical UniversitySyracuseNew York
| | | | - Roger Robert Lebel
- Center for Development, Behavior, and GeneticsSUNY Upstate Medical UniversitySyracuseNew York
| | - Ai Sakonju
- Department of NeurologySUNY Upstate Medical UniversitySyracuseNew York
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Hoch MJ, Bruno MT, Faustin A, Cruz N, Mogilner AY, Crandall L, Wisniewski T, Devinsky O, Shepherd TM. 3T MRI Whole-Brain Microscopy Discrimination of Subcortical Anatomy, Part 2: Basal Forebrain. AJNR Am J Neuroradiol 2019; 40:1095-1105. [PMID: 31196861 DOI: 10.3174/ajnr.a6088] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2019] [Accepted: 04/22/2019] [Indexed: 12/13/2022]
Abstract
BACKGROUND AND PURPOSE The basal forebrain contains multiple structures of great interest to emerging functional neurosurgery applications, yet many neuroradiologists are unfamiliar with this neuroanatomy because it is not resolved with current clinical MR imaging. MATERIALS AND METHODS We applied an optimized TSE T2 sequence to washed whole postmortem brain samples (n = 13) to demonstrate and characterize the detailed anatomy of the basal forebrain using a clinical 3T MR imaging scanner. We measured the size of selected internal myelinated pathways and measured subthalamic nucleus size, oblique orientation, and position relative to the intercommissural point. RESULTS We identified most basal ganglia and diencephalon structures using serial axial, coronal, and sagittal planes relative to the intercommissural plane. Specific oblique image orientations demonstrated the positions and anatomic relationships for selected structures of interest to functional neurosurgery. We observed only 0.2- to 0.3-mm right-left differences in the anteroposterior and superoinferior length of the subthalamic nucleus (P = .084 and .047, respectively). Individual variability for the subthalamic nucleus was greatest for angulation within the sagittal plane (range, 15°-37°), transverse dimension (range, 2-6.7 mm), and most inferior border (range, 4-7 mm below the intercommissural plane). CONCLUSIONS Direct identification of basal forebrain structures in multiple planes using the TSE T2 sequence makes this challenging neuroanatomy more accessible to practicing neuroradiologists. This protocol can be used to better define individual variations relevant to functional neurosurgical targeting and validate/complement advanced MR imaging methods being developed for direct visualization of these structures in living patients.
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Affiliation(s)
- M J Hoch
- From the Department of Radiology and Imaging Sciences, (M.J.H.), Emory University, Atlanta, Georgia
| | - M T Bruno
- Departments of Radiology (M.T.B., N.C., T.M.S.)
| | | | - N Cruz
- Departments of Radiology (M.T.B., N.C., T.M.S.)
| | | | - L Crandall
- Neurology (L.C., T.W., O.D.).,SUDC Foundation (L.C., O.D.), New York, New York
| | - T Wisniewski
- Pathology (A.F., T.W.).,Neurology (L.C., T.W., O.D.).,Psychiatry (T.W.), New York University, New York, New York
| | - O Devinsky
- Neurology (L.C., T.W., O.D.).,SUDC Foundation (L.C., O.D.), New York, New York
| | - T M Shepherd
- Departments of Radiology (M.T.B., N.C., T.M.S.) .,Center for Advanced Imaging Innovation and Research (T.M.S.), New York, New York
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Hoch MJ, Bruno MT, Faustin A, Cruz N, Crandall L, Wisniewski T, Devinsky O, Shepherd TM. 3T MRI Whole-Brain Microscopy Discrimination of Subcortical Anatomy, Part 1: Brain Stem. AJNR Am J Neuroradiol 2019; 40:401-407. [PMID: 30705073 DOI: 10.3174/ajnr.a5956] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Accepted: 12/12/2018] [Indexed: 12/19/2022]
Abstract
BACKGROUND AND PURPOSE The brain stem is compactly organized with life-sustaining sensorimotor and autonomic structures that can be affected by numerous pathologies but can be difficult to resolve on conventional MR imaging. MATERIALS AND METHODS We applied an optimized TSE T2 sequence to washed postmortem brain samples to reveal exquisite and reproducible brain stem anatomic MR imaging contrast comparable with histologic atlases. This resource-efficient approach can be performed across multiple whole-brain samples with relatively short acquisition times (2 hours per imaging plane) using clinical 3T MR imaging systems. RESULTS We identified most brain stem structures at 7 canonical axial levels. Multiplanar or oblique planes illustrate the 3D course and spatial relationships of major brain stem white matter pathways. Measurements of the relative position, course, and cross-sectional area of these pathways across multiple samples allow estimation of pathway location in other samples or clinical subjects. Possible structure-function asymmetries in these pathways will require further study-that is, the cross-sectional area of the left corticospinal tract in the midpons appeared 20% larger (n = 13 brains, P < .10). CONCLUSIONS Compared with traditional atlases, multiplanar MR imaging contrast has advantages for learning and retaining brain stem anatomy for clinicians and trainees. Direct TSE MR imaging sequence discrimination of brain stem anatomy can help validate other MR imaging contrasts, such as diffusion tractography, or serve as a structural template for extracting quantitative MR imaging data in future postmortem investigations.
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Affiliation(s)
- M J Hoch
- From the Department of Radiology and Imaging Sciences (M.J.H.), Emory University, Atlanta, Georgia
| | - M T Bruno
- Departments of Radiology (M.T.B., N.C., T.M.S.)
| | | | - N Cruz
- Departments of Radiology (M.T.B., N.C., T.M.S.)
| | - L Crandall
- Neurology (L.C., T.W., O.D.)
- SUDC Registry and Research Collaborative (L.C., O.D.), New York, New York
| | - T Wisniewski
- Neurology (L.C., T.W., O.D.)
- Psychiatry (T.W.), New York University, New York, New York
| | - O Devinsky
- Neurology (L.C., T.W., O.D.)
- SUDC Registry and Research Collaborative (L.C., O.D.), New York, New York
| | - T M Shepherd
- Departments of Radiology (M.T.B., N.C., T.M.S.)
- Center for Advanced Imaging Innovation and Research (T.M.S.), New York, New York
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Wang C, Ren H, Dong H, Liang M, Wu Q, Liao Y. 18q22.1-qter deletion and 4p16.3 microduplication in a boy with speech delay and mental retardation: case report and review of the literature. Mol Cytogenet 2018; 11:55. [PMID: 30377449 PMCID: PMC6194714 DOI: 10.1186/s13039-018-0404-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Accepted: 10/01/2018] [Indexed: 11/13/2022] Open
Abstract
Background Deletions involving the long arm of chromosome 18 have been associated with a highly variable phenotypic spectrum that is related to the extent of the deleted region. Duplications in chromosomal region 4p16.3 have also been shown to cause 4p16.3 microduplication syndrome. Most reported patients of trisomy 4p16.3 have more duplications, including the Wolf-Hirschhorn critical region (WHSCR). Here, we present a patient with speech delay and mental retardation caused by a deletion of 18q (18q22.1-qter) and terminal microduplication of 4p (4p16.3-pter) distal to WHSCR. Case presentation The patient was a 23-month-old boy with moderate growth retardation, severe speech delay, mental retardation, and dysmorphic features. Single nucleotide polymorphism (SNP) array analysis confirmed an 11.2-Mb terminal deletion at 18q22.1 and revealed a 1.8-Mb terminal duplication of 4p16.3. Our patient showed clinical overlap with these two syndromes, although his overall features were milder than what had been previously described. Some dosage-sensitive genes on the 18q terminal deleted region and 4p16.3 duplicated region of the present case may have contributed to his phenotype. Conclusions This is the first report of a patient with combined terminal deletion of 18q22.1 and duplication of 4p16.3. In this report, we provide clinical and molecular evidence supporting that the microduplication in 4p16.3, distal to WHSCR, is pathogenic. The coexistence of two chromosome aberrations complicates the clinical picture and creates a chimeric phenotype. This report provides further information on the genotype-phenotype correlation of 18q terminal deletion and 4p microduplication.
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Affiliation(s)
- Chunjing Wang
- 1Department of Life Sciences, Bengbu Medical College, 2600 Donghai Avenue, Bengbu, Anhui 233030 People's Republic of China
| | - Huanhuan Ren
- 1Department of Life Sciences, Bengbu Medical College, 2600 Donghai Avenue, Bengbu, Anhui 233030 People's Republic of China
| | - Huaifu Dong
- 2Department of Paediatrics, The First Affiliated Hospital of Bengbu Medical College, 2600 Donghai Avenue, Bengbu, Anhui China
| | - Meng Liang
- 1Department of Life Sciences, Bengbu Medical College, 2600 Donghai Avenue, Bengbu, Anhui 233030 People's Republic of China
| | - Qi Wu
- 1Department of Life Sciences, Bengbu Medical College, 2600 Donghai Avenue, Bengbu, Anhui 233030 People's Republic of China
| | - Yaping Liao
- 1Department of Life Sciences, Bengbu Medical College, 2600 Donghai Avenue, Bengbu, Anhui 233030 People's Republic of China
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Hypomyelinating disorders in China: The clinical and genetic heterogeneity in 119 patients. PLoS One 2018; 13:e0188869. [PMID: 29451896 PMCID: PMC5815574 DOI: 10.1371/journal.pone.0188869] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2017] [Accepted: 11/14/2017] [Indexed: 01/08/2023] Open
Abstract
OBJECTIVE Hypomyelinating disorders are a group of clinically and genetically heterogeneous diseases characterized by neurological deterioration with hypomyelination visible on brain MRI scans. This study was aimed to clarify the clinical and genetic features of HMDs in Chinese population. METHODS 119 patients with hypomyelinating disorders in Chinese population were enrolled and evaluated based on their history, clinical manifestation, laboratory examinations, series of brain MRI with follow-up, genetic etiological tests including chromosomal analysis, multiplex ligation probe amplification, Sanger sequencing, targeted enrichment-based next-generation sequencing and whole exome sequencing. RESULTS Clinical and genetic features of hypomyelinating disorders were revealed. Nine different hypomyelinating disorders were identified in 119 patients: Pelizaeus-Merzbacher disease (94, 79%), Pelizaeus-Merzbacher-like disease (10, 8%), hypomyelination with atrophy of the basal ganglia and cerebellum (3, 3%), GM1 gangliosidosis (5, 4%), GM2 gangliosidosis (3, 3%), trichothiodystrophy (1, 1%), Pol III-related leukodystrophy (1, 1%), hypomyelinating leukodystrophy type 9 (1, 1%), and chromosome 18q deletion syndrome (1, 1%). Of the sample, 94% (112/119) of the patients were genetically diagnosed, including 111 with mutations distributing across 9 genes including PLP1, GJC2, TUBB4A, GLB1, HEXA, HEXB, ERCC2, POLR3A, and RARS and 1 with mosaic chromosomal change of 46, XX,del(18)(q21.3)/46,XX,r(18)(p11.32q21.3)/45,XX,-18. Eighteen novel mutations were discovered. Mutations in POLR3A and RARS were first identified in Chinese patients with Pol III-related leukodystrophy and hypomyelinating leukodystrophy, respectively. SIGNIFICANCE This is the first report on clinical and genetic features of hypomyelinating disorders with a large sample of patients in Chinese population, identifying 18 novel mutations especially mutations in POLR3A and RARS in Chinese patients, expanding clinical and genetic spectrums of hypomyelinating disorders.
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Lin Q, Huang WQ, Tzeng CM. Genetic associations of leukoaraiosis indicate pathophysiological mechanisms in white matter lesions etiology. Rev Neurosci 2015; 26:343-58. [PMID: 25781674 DOI: 10.1515/revneuro-2014-0082] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2014] [Accepted: 12/18/2014] [Indexed: 11/15/2022]
Abstract
Leukoaraiosis (LA), also called white matter lesions (WMLs) and white matter hyperintensities (WMHs), is a frequent neuroimaging finding commonly seen on magnetic resonance imaging brain scans of elderly people with prevalence ranging from 50% to 100%. Although it remains asymptomatic, LA is not considered to be benign, and it is showed to be related to a host of poor clinical outcomes and increases the risk of disability, dementia, depression, stroke, and the overall morbidity and mortality. Pathologically, LA is characterized by loss of myelin and axons, patchy demyelination, and denudation of ependyma in regions of WMH. Age and hypertension are the most importantly established risk factors for LA. However, the precise pathogenic mechanisms remain unclear. Together with the previous findings, our recent genetic results strongly supported that LA is associated with immune response and neuroinflammation. Therefore, we confidently hypothesized that LA was not only a common neuroimaging phenomenon in the elderly but also an emerging neuroinflammatory disorder in the central nervous system. This article focusing on neuroimaging classification, genetics basis, and putative molecular mechanism introduced the basic knowledge and current status of LA and put forward some of our research ideas and results from our molecular genetics research, which may pave the way for deciphering the putative pathogenic mechanism, risk factor, epigenetic index, and its application in diagnostic agents or drug target for prevention and treatment. Thus, it could provide clinicians and researchers with a specific and modern overview of LA to enable the understanding of recent progress and future directions in this illness.
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Cody JD, Sebold C, Heard P, Carter E, Soileau B, Hasi-Zogaj M, Hill A, Rupert D, Perry B, O'Donnell L, Gelfond J, Lancaster J, Fox PT, Hale DE. Consequences of chromsome18q deletions. AMERICAN JOURNAL OF MEDICAL GENETICS PART C-SEMINARS IN MEDICAL GENETICS 2015; 169:265-80. [PMID: 26235940 DOI: 10.1002/ajmg.c.31446] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2015] [Accepted: 06/28/2015] [Indexed: 11/11/2022]
Abstract
Providing clinically relevant prognoses and treatment information for people with a chromsome18q deletion is particularly challenging because every unrelated person has a unique region of hemizygosity. The hemizygous region can involve almost any region of 18q including between 1 and 101 genes (30 Mb of DNA). Most individuals have terminal deletions, but in our cohort of over 350 individuals 23% have interstitial deletions. Because of this heterogeneity, we take a gene by gene approach to understanding the clinical consequences. There are 196 genes on 18q. We classified 133 of them as dosage insensitive, 15 (8%) as dosage sensitive leading to haploinsufficiency while another 10 (5%) have effects that are conditionally haploinsufficient and are dependent on another factor, genetic or environmental in order to cause an abnormal phenotype. Thirty-seven genes (19%) have insufficient information to classify their dosage effect. Phenotypes attributed to single genes include: congenital heart disease, minor bone morphology changes, central nervous system dysmyelination, expressive speech delay, vesicouretreral reflux, polyposis, Pitt-Hopkins syndrome, intellectual disability, executive function impairment, male infertility, aural atresia, and high frequency sensorineural hearing loss. Additionally, identified critical regions for other phenotypes include: adolescent idiopathic scoliosis and pectus excavatum, Virchow-Robin perivascular spaces, small corpus callosum, strabismus, atopic disorders, mood disorder, IgA deficiency, nystagmus, congenital heart disease, kidney malformation, vertical talus, CNS dysmyelination growth hormone deficiency and cleft palate. Together these findings make it increasingly feasible to compile an individualized syndrome description based on each person's individuated genotype. Future work will focus on understanding molecular mechanisms leading to treatment.
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Abstract
OBJECTIVE The objective of this study was to characterize hearing loss in individuals with deletions of distal chromsome18q and to identify the smallest region of overlap of their deletions, thereby identifying potential causative genes. STUDY DESIGN The clinical data were collected via a retrospective case study. Molecular data were obtained via high-resolution chromosome microarray analysis. SETTING The study was conducted as a component of the ongoing research protocols at the Chromosome 18 Clinical Research Center at the University of Texas Health Science Center at San Antonio. PATIENTS Thirty-eight participants with a deletion of the distal portion of the long arm of chromosome 18 were recruited to this study. INTERVENTIONS The participants underwent an otologic examination as well as a basic audiometry evaluation. Blood samples were obtained, and high-resolution chromosome microarray analysis was performed. MAIN OUTCOMES MEASURES Pure tone averages and speech discrimination scores were determined for each participant. The region of hemizygosity for each participant was determined to within 2 Kb each of their breakpoints. RESULTS Twenty-four participants (63%) had high-frequency hearing loss, similar to the pattern seen in presbycusis. Comparison of microarray results allowed identification of eight genes, including the candidate gene for dysmyelination (MBP). CONCLUSION Individuals with a deletion of a 2.8 Mb region of 18q23 have a high probability (83%) of high-frequency sensorineural hearing loss.
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Tada H, Takanashi JI. MR spectroscopy in 18q(-) syndrome suggesting other than hypomyelination. Brain Dev 2014; 36:57-60. [PMID: 23332863 DOI: 10.1016/j.braindev.2012.12.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/12/2012] [Revised: 09/17/2012] [Accepted: 12/06/2012] [Indexed: 11/17/2022]
Abstract
We reported a 5-year-old boy with 18q(-) syndrome who showed typical magnetic resonance imaging (MRI) findings of high signal intensity on T2-weighted imaging, and a slightly high but lower than normal signal on T1-weighted imaging of the white matter. MR spectroscopy (MRS) revealed increased concentrations of creatine, myoinositol and choline with a normal N-acetylaspartate one. The cerebral white matter lesions observed on MRI in patients with 18q(-) syndrome have been considered to reflect hypomyelination due to a decrease in myelin basic protein so far, however, MRS suggested reactive astrocytic gliosis and accelerated myelin turnover, which are compatible with recent pathological reports of 18q(-) syndrome.
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Affiliation(s)
- Hiroko Tada
- Department of Pediatrics, Chibaken Saiseikai Narashino Hospital, Narashino, Japan.
| | - Jun-ichi Takanashi
- Department of Pediatrics, Kameda Medical Center, Kamogawa, Japan; Department of Radiology, Toho University Sakura Medical Center, Sakura, Japan
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Combined deletion 18q22.2 and duplication/triplication 18q22.1 causes microcephaly, mental retardation and leukencephalopathy. Gene 2013; 523:92-8. [DOI: 10.1016/j.gene.2013.03.078] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2012] [Revised: 02/05/2013] [Accepted: 03/15/2013] [Indexed: 11/23/2022]
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Mark PR, Radlinski BC, Core N, Fryer A, Kirk EP, Haldeman-Englert CR. Narrowing the critical region for congenital vertical talus in patients with interstitial 18q deletions. Am J Med Genet A 2013; 161A:1117-21. [PMID: 23495172 DOI: 10.1002/ajmg.a.35791] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2012] [Accepted: 10/31/2012] [Indexed: 11/11/2022]
Abstract
Interstitial deletions of 18q lead to a number of phenotypic features, including multiple types of foot deformities. Many of these associated phenotypes have had their critical regions narrowly defined. Here we report on three patients with small overlapping deletions of chromosome 18q determined by microarray analysis (chr18:72493281-73512553 hg19 coordinates). All of the patients have congenital vertical talus (CVT). Based on these findings and previous reports in the literature and databases, we narrow the critical region for CVT to a minimum of five genes (ZNF407, ZADH2, TSHZ1, C18orf62, and ZNF516), and propose that TSHZ1 is the likely causative gene for CVT in 18q deletion syndrome.
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Affiliation(s)
- Paul R Mark
- Department of Medical Genetics, Spectrum Health, Grand Rapids, MI 49503, USA.
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Benini R, Saint-Martin C, Shevell MI, Bernard G. Abnormal myelination in ring chromosome 18 syndrome. J Child Neurol 2012; 27:1042-7. [PMID: 22290857 DOI: 10.1177/0883073811430268] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Partial deletion of genetic material from the long arm of chromosome 18 results in a syndrome with multisystemic involvement, including dysmorphic features, intellectual disability, cardiac malformations, endocrine abnormalities, immunodeficiency, musculoskeletal deformities, and variable neurologic manifestations. Hypomyelination has been reported in patients with chromosome 18q- and postulated to be secondary to deletion of the gene coding for myelin basic protein found at 18q23. Little however is reported on cerebral anomalies seen in patients with ring chromosome 18, an analogous syndrome but with expectedly more severe phenotype secondary to the combined deletions of genetic material from both the short (p-) and long arm (q-) of chromosome 18. We are reporting a case of a girl with ring chromosome 18 and deletions involving 18p11.32-18p11.21 and 18q21.31-18q23. The abnormalities observed on magnetic resonance imaging are discussed with a specific focus on the evolution and significance of associated white matter changes.
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Affiliation(s)
- Ruba Benini
- Division of Pediatric Neurology, McGill University, Montreal, Quebec, Canada
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NF-κB signalling requirement for brain myelin formation is shown by genotype/MRI phenotype correlations in patients with Xq28 duplications. Eur J Hum Genet 2012; 21:195-9. [PMID: 22805531 DOI: 10.1038/ejhg.2012.140] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
One of the key signals regulating peripheral myelin formation by Schwann cell is the activation of the transcription factor NF-κB. Yet, whether NF-κB exerts similar functions in central myelin formation by oligodendrocytes remains largely unknown. We previously reported white matter abnormalities with unusual discordance between T2 and FLAIR sequences in a patient with intellectual disability and defective NF-κB signalling. These observations prompted us to hypothesise that NF-κB signalling may have a role in the axon myelination process of central neurons. We report here on five male patients with Xq28 duplications encompassing MECP2, three of which presented white matter anomalies on brain MRI. Array-CGH and FISH analyses demonstrated that brain abnormalities correlate with additional copies of the IKBKG, a gene encoding a key regulator of NF-κB activation. Quantitative RT-PCR experiments and κB-responsive reporter gene assays provide evidence that IKBKG overexpression causes impaired NF-κB signalling in skin fibroblasts derived from patients with white matter anomalies. These data further support the role of NF-κB signalling in astroglial cells for normal myelin formation of the central nervous system.
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Tanaka R, Iwasaki N, Hayashi M, Nakayama J, Ohto T, Takahashi M, Numano T, Homma K, Hamano K, Sumazaki R. Abnormal brain MRI signal in 18q-syndrome not due to dysmyelination. Brain Dev 2012; 34:234-7. [PMID: 21669507 DOI: 10.1016/j.braindev.2011.05.008] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/18/2010] [Revised: 05/11/2011] [Accepted: 05/16/2011] [Indexed: 10/18/2022]
Abstract
BACKGROUND 18q-Syndrome is a chromosomal disorder exhibiting various symptoms arising from the central nervous system. Brain magnetic resonance imaging (MRI) of patients with this syndrome usually demonstrates abnormal white matter intensities. This is widely believed to be due to impaired myelin formation because this syndrome involves the deletion of the myelin basic protein (MBP) gene in 18q23. However, this hypothesis has not been confirmed by actual pathology because early death is unusual and autopsy rarely performed. PATIENT A 6-year-old boy with ring chromosome 18 syndrome was examined by genetic analysis for the MBP gene, brain MRI, and autopsy. RESULTS Haploinsufficiency of the MBP gene was confirmed. T(2)-weighted MRI revealed diffuse high intensities throughout the cerebral white matter. Pathological examination showed the cerebral white matter to be uniformly stained by Klüver-Barrera and MBP immunohistochemical staining. Oligodendrocytes were immunoreactive for proteolipid protein and ferritin but not MBP. Electron microscopy revealed clusters of axons wrapped in compact myelin sheaths with distinct major dense lines. Holzer and immunohistochemical staining for glial fibrillary acidic protein showed extensive staining of the white matter and an increased number of glial filaments. CONCLUSIONS This pathological study demonstrated that in this disorder, the brain was well myelinated, contrary to established hypotheses about this disorder. The MRI signal abnormalities in 18q-syndrome could be attributed to gliosis and not to dysmyelination.
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Affiliation(s)
- Ryuta Tanaka
- Department of Child Health, Institute of Clinical Medicine, University of Tsukuba, Tsukuba, Ibaraki, Japan.
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Margarit E, Morales C, Rodríguez-Revenga L, Monné R, Badenas C, Soler A, Clusellas N, Mademont I, Sánchez A. Familial 4.8 MB deletion on 18q23 associated with growth hormone insufficiency and phenotypic variability. Am J Med Genet A 2012; 158A:611-6. [PMID: 22302430 DOI: 10.1002/ajmg.a.34221] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2010] [Accepted: 05/23/2011] [Indexed: 11/07/2022]
Abstract
The deletion of the long arm of chromosome 18 causes a contiguous gene deletion syndrome with a highly variable phenotype, usually related to the extent of the deleted region. The most commonly reported clinical features include: decreased growth, microcephaly, facial abnormalities, hypotonia, developmental delay, intellectual disability, congenital aural atresia with hearing impairment and limb anomalies. Here we report on a familial terminal deletion of 18q23 region transmitted from a mother to two daughters, resulting in a remarkable phenotypic variability. The deletion was first detected by conventional cytogenetic analysis in one daughter and subsequently characterized using fluorescence in situ hybridization (FISH) and array-CGH. FISH analysis using subtelomeric 18p and 18q probes confirmed the 18qter deletion in the three patients, and FISH with a whole chromosome painting probe specific for chromosome 18 excluded rearrangements with other chromosomes. Array-CGH analysis allowed us to precisely define the extent of the deletion, which spans 4.8 Mb from 71,236,891 to 76,093,303 genomic positions and includes GALR1 and MBP genes, among others. High-resolution analysis of the deletion, besides a detailed clinical assessment, has provided important data for phenotype-genotype correlation and genetic counseling in this family. Furthermore, this study adds valuable information for phenotype-genotype correlation in 18q- syndrome and might facilitate future search for candidate genes involved in each phenotypic trait.
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Affiliation(s)
- Ester Margarit
- Biochemistry and Molecular Genetics, Hospital Clínic, Barcelona, Spain.
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17
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Steenweg ME, Vanderver A, Blaser S, Bizzi A, de Koning TJ, Mancini GMS, van Wieringen WN, Barkhof F, Wolf NI, van der Knaap MS. Magnetic resonance imaging pattern recognition in hypomyelinating disorders. ACTA ACUST UNITED AC 2010; 133:2971-82. [PMID: 20881161 DOI: 10.1093/brain/awq257] [Citation(s) in RCA: 183] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Hypomyelination is observed in the context of a growing number of genetic disorders that share clinical characteristics. The aim of this study was to determine the possible role of magnetic resonance imaging pattern recognition in distinguishing different hypomyelinating disorders, which would facilitate the diagnostic process. Only patients with hypomyelination of known cause were included in this retrospective study. A total of 112 patients with Pelizaeus-Merzbacher disease, hypomyelination with congenital cataract, hypomyelination with hypogonadotropic hypogonadism and hypodontia, Pelizaeus-Merzbacher-like disease, infantile GM1 and GM2 gangliosidosis, Salla disease and fucosidosis were included. The brain scans were rated using a standard scoring list; the raters were blinded to the diagnoses. Grouping of the patients was based on cluster analysis. Ten clusters of patients with similar magnetic resonance imaging abnormalities were identified. The most important discriminating items were early cerebellar atrophy, homogeneity of the white matter signal on T(2)-weighted images, abnormal signal intensity of the basal ganglia, signal abnormalities in the pons and additional T(2) lesions in the deep white matter. Eight clusters each represented mainly a single disorder (i.e. Pelizaeus-Merzbacher disease, hypomyelination with congenital cataract, hypomyelination with hypogonadotropic hypogonadism and hypodontia, infantile GM1 and GM2 gangliosidosis, Pelizaeus-Merzbacher-like disease and fucosidosis); only two clusters contained multiple diseases. Pelizaeus-Merzbacher-like disease was divided between two clusters and Salla disease did not cluster at all. This study shows that it is possible to separate patients with hypomyelination disorders of known cause in clusters based on magnetic resonance imaging abnormalities alone. In most cases of Pelizaeus-Merzbacher disease, hypomyelination with congenital cataract, hypomyelination with hypogonadotropic hypogonadism and hypodontia, Pelizaeus-Merzbacher-like disease, infantile GM1 and GM2 gangliosidosis and fucosidosis, the imaging pattern gives clues for the diagnosis.
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Affiliation(s)
- Marjan E Steenweg
- Department of Child Neurology, VU University Medical Center, De Boelelaan 1117, Amsterdam, The Netherlands
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Kakisaka Y, Wakusawa K, Sato I, Haginoya K, Uematsu M, Hirose M, Munakata M, Sato T, Tsuchiya S. Successful treatment with sumatriptan in a case with cyclic vomiting syndrome combined with 18q- syndrome. J Child Neurol 2009; 24:1561-3. [PMID: 19794103 DOI: 10.1177/0883073809334384] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The authors present a 14-year-old girl with 18q- syndrome combined with cyclic vomiting syndrome. Since the age of 5 years, she has been admitted to hospital 30 times. Despite trying many prophylactic treatments, no medication has inhibited the vomiting attacks successfully. Intranasal sumatriptan was effective at halting the vomiting attacks. This is the first case of 18q- syndrome combined with cyclic vomiting syndrome successfully treated with sumatriptan. This report may allow us to consider sumatriptan use in patients suffering from misery attack of cyclic vomiting syndrome combined with chromosomal abnormality of 18q- syndrome.
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Affiliation(s)
- Yosuke Kakisaka
- Department of Pediatrics, Tohoku University School of Medicine, Sendai, Miyagi, Japan.
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19
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Cody JD, Heard PL, Crandall AC, Carter EM, Li J, Hardies LJ, Lancaster J, Perry B, Stratton RF, Sebold C, Schaub RL, Soileau B, Hill A, Hasi M, Fox PT, Hale DE. Narrowing critical regions and determining penetrance for selected 18q- phenotypes. Am J Med Genet A 2009; 149A:1421-30. [PMID: 19533771 DOI: 10.1002/ajmg.a.32899] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
One of our primary goals is to help families who have a child with an 18q deletion anticipate medical issues in order to optimize their child's medical care. To this end we have narrowed the critical regions for four phenotypic features and determined the penetrance for each of those phenotypes when the critical region for that feature is hemizygous. We completed molecular analysis using oligo-array CGH and clinical assessments on 151 individuals with deletions of 18q and made genotype-phenotype correlations defining or narrowing critical regions. These nested regions, all within 18q22.3 to q23, were for kidney malformations, dysmyelination of the brain, growth hormone stimulation response failure, and aural atresia. The region for dysmyelination and growth hormone stimulation response failure were identical and was narrowed to 1.62 Mb, a region containing five known genes. The region for aural atresia was 2.3 Mb and includes an additional three genes. The region for kidney malformations was 3.21 Mb and includes an additional four genes. Penetrance rates were calculated by comparing the number of individuals hemizygous for a critical region with the phenotype to those without the phenotype. The kidney malformations region was 25% penetrant, the dysmyelination region was 100% penetrant, the growth hormone stimulant response failure region was 90% penetrant with variable expressivity, and the aural atresia region was 78% penetrant. Identification of these critical regions suggest possible candidate genes, while penetrance calculations begin to create a predictive phenotypic description based on genotype.
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Affiliation(s)
- Jannine D Cody
- Department of Pediatrics, University of Texas Health Science Center at San Antonio, San Antonio, Texas 78229, USA.
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20
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Dostal A, Nemeckova J, Gaillyova R. The 18q deletion syndrome and analysis of the critical region for orofacial cleft at 18q22.3. J Craniomaxillofac Surg 2009; 37:272-5. [PMID: 19157891 DOI: 10.1016/j.jcms.2008.12.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2008] [Revised: 11/28/2008] [Accepted: 12/17/2008] [Indexed: 11/28/2022] Open
Abstract
INTRODUCTION The 18q deletion syndrome (18q-) is a multiple-anomaly disorder associated with mental retardation, white matter anomalies in the brain, growth hormone deficiency, congenital aural atresia, orofacial cleft (OFC), and palate abnormalities. The aims of this study were to determine the frequency of different forms of OFC in 18q- individuals: cleft palate with or without cleft lip (CP/L), cleft lip (CL), and palate abnormalities. We also sought to map a potential critical region for OFC within chromosome 18q22.3 region. PATIENTS The study presents an overview of selected 18q- individuals from 11 published reports and one presented poster. RESULTS The frequency of CP/L and CL among 18q- individuals is about 25%; when high/arched palate cases are included, the frequency rises to about 43%. CONCLUSION Orofacial abnormalities are characteristic features of 18q- syndrome patients and potential CP/L critical region could be assumed at 18q22.3 between markers D18S879 and D18S1141. In addition, gene deficient mouse models for Sall3 or Tshz1 genes, which are located at the 18q22.3 critical region, displayed palate abnormality phenotype.
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Affiliation(s)
- Ales Dostal
- Hematology-Oncology, Children's Hospital Boston, MA, USA.
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21
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Abstract
The 18q deletion syndrome (18q-) is a chromosomal disorder involving deletion of the distal segment of chromosome 18. Typifying features include poor cerebral myelination, reduced intellectual functioning and developmental delay. The present study reports the case of an 8-year-old girl diagnosed with 18q-, whose genetic analysis revealed a break at q21.3. Comprehensive neuropsychological testing indicated impaired functioning across most cognitive domains. However, verbal abilities were intact. Given the preservation of verbal skills on a background of relatively global impairment, CB's genetic and cognitive profile has implications for delineation of neuropsychological features associated with specific breakpoints in 18q-.
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Affiliation(s)
- Deborah Arguedas
- Department of Psychology, Macquarie University, Sydney, Australia.
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Gereltzul E, Baba Y, Suda N, Shiga M, Inoue MS, Tsuji M, Shin I, Hirata Y, Ohyama K, Moriyama K. Case report of de novo dup(18p)/del(18q) and r(18) mosaicism. J Hum Genet 2008; 53:941-946. [PMID: 18679767 DOI: 10.1007/s10038-008-0326-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2007] [Accepted: 07/08/2008] [Indexed: 11/29/2022]
Abstract
This is a report of a 27-year-old woman with an unusual de novo chromosomal abnormality. Mosaicism was identified in peripheral blood cells examined by standard G-bands by trypsin using Giemsa (GTG) analysis and fluorescence in situ hybridization (FISH) analysis with chromosome-18 region-specific probes, 46,XX,del(18)(pter --> q21.33:)[41], 46,XX,r(18)(::p11.21 --> q21.33::)[8], and 46,XX,der(18)(pter --> q21.33::p11.21 --> pter)[1]. On the other hand, the karyotype of periodontal ligament fibroblasts was nonmosaic, 46,XX, der(18)(pter --> q21.33::p11.21 --> pter)[50]. All cell lines appeared to be missing a portion of 18q (q21.33 --> qter). The pattern of the dup(18p)/del(18q) in the rod configuration raises the possibility of an inversion in chromosome 18 in one of the parents. However, no chromosomal anomaly was detected in either parent. The most probable explanation is that de novo rod and ring configurations arose simultaneously from an intrachromosomal exchange. The unique phenotype of this patient, which included primary hypothyroidism and primary hypogonadism, is discussed in relation to her karyotype.
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Affiliation(s)
- Enkhtuvshin Gereltzul
- Maxillofacial Orthognathics, Graduate School, Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo-Ku, Tokyo, 113-8549, Japan
| | - Yoshiyuki Baba
- Maxillofacial Orthognathics, Graduate School, Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo-Ku, Tokyo, 113-8549, Japan.
| | - Naoto Suda
- Maxillofacial Orthognathics, Graduate School, Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo-Ku, Tokyo, 113-8549, Japan
| | - Momotoshi Shiga
- Maxillofacial Orthognathics, Graduate School, Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo-Ku, Tokyo, 113-8549, Japan
| | - Maristela Sayuri Inoue
- Maxillofacial Orthognathics, Graduate School, Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo-Ku, Tokyo, 113-8549, Japan
| | - Michiko Tsuji
- Maxillofacial Orthognathics, Graduate School, Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo-Ku, Tokyo, 113-8549, Japan
| | - Insik Shin
- Maxillofacial Orthognathics, Graduate School, Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo-Ku, Tokyo, 113-8549, Japan
| | - Yukio Hirata
- Clinical and Molecular Endocrinology, Graduate School, Tokyo Medical and Dental University, Tokyo, Japan
| | - Kimie Ohyama
- Maxillofacial Orthognathics, Graduate School, Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo-Ku, Tokyo, 113-8549, Japan
| | - Keiji Moriyama
- Maxillofacial Orthognathics, Graduate School, Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo-Ku, Tokyo, 113-8549, Japan
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Tohyama J, Akasaka N, Osaka H, Maegaki Y, Kato M, Saito N, Yamashita S, Ohno K. Early onset West syndrome with cerebral hypomyelination and reduced cerebral white matter. Brain Dev 2008; 30:349-55. [PMID: 18065176 DOI: 10.1016/j.braindev.2007.10.006] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/16/2007] [Revised: 10/08/2007] [Accepted: 10/13/2007] [Indexed: 10/22/2022]
Abstract
Numerous numbers of pre-, peri- and postnatal damages cause West syndrome in early infancy, however, etiology in many cases are not still elucidated despite intensive biochemical and neuroradiologic investigations. We described four patients having early onset epileptic encephalopathy with severe hypomyelination and reduction in cerebral white matter. The clinical symptoms of these patients are impaired visual attention, acquired microcephaly, spastic tetraplegia, profound psychomotor delay and infantile spasms since early infancy. All patients had striking hypomyelination of cerebrum, reduced volume of white matter and cortical atrophy on MRI. Serial MRI investigations in three patients showed absence of myelination of the white matter. On EEG, one patient revealed suppression-burst and other three had hypsarrhythmia. Despite having intractable seizures, no patient showed deterioration of neurological development. The group of these findings is mimicking to clinical manifestations of 3-phosphoglycerate dehydrogenase deficiency, and has some overlap with progressive encephalopathy with edema, hypsarrhythmia, and optic atrophy (PEHO) like syndrome, however it is not compatible with these two conditions. The findings observed in our patients can be regarded as a new clinical condition associated with early onset West syndrome.
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Affiliation(s)
- Jun Tohyama
- Department of Pediatrics, Epilepsy Center, Nishi-Niigata Chuo National Hospital, 1-14-1 Masago, Nishi-ku, Niigata-city, Niigata 950-2085, Japan.
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24
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Feenstra I, Vissers LELM, Orsel M, van Kessel AG, Brunner HG, Veltman JA, van Ravenswaaij-Arts CMA. Genotype-phenotype mapping of chromosome 18q deletions by high-resolution array CGH: an update of the phenotypic map. Am J Med Genet A 2007; 143A:1858-67. [PMID: 17632778 DOI: 10.1002/ajmg.a.31850] [Citation(s) in RCA: 93] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Partial deletions of the long arm of chromosome 18 lead to variable phenotypes. Common clinical features include a characteristic face, short stature, congenital aural atresia (CAA), abnormalities of the feet, and mental retardation (MR). The presence or absence of these clinical features may depend on the size and position of the deleted region. Conversely, it is also known that patients whose breakpoints are localized within the same chromosome band may exhibit distinct phenotypes. New molecular techniques such as array CGH allow for a more precise determination of breakpoints in cytogenetic syndromes, thus leading to better-defined genotype-phenotype correlations. In order to update the phenotypic map for chromosome 18q deletions, we applied a tiling resolution chromosome 18 array to determine the exact breakpoints in 29 patients with such deletions. Subsequently, we linked the genotype to the patient's phenotype and integrated our results with those previously published. Using this approach, we were able to refine the critical regions for microcephaly (18q21.33), short stature (18q12.1-q12.3, 18q21.1-q21.33, and 18q22.3-q23), white matter disorders and delayed myelination (18q22.3-q23), growth hormone insufficiency (18q22.3-q23), and CAA (18q22.3). Additionally, the overall level of MR appeared to be mild in patients with deletions distal to 18q21.33 and severe in patients with deletions proximal to 18q21.31. The critical region for the 'typical' 18q-phenotype is a region of 4.3 Mb located within 18q22.3-q23. Molecular characterization of more patients will ultimately lead to a further delineation of the critical regions and thus to the identification of candidate genes for these specific traits.
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Affiliation(s)
- Ilse Feenstra
- Department of Human Genetics, University Medical Centre Nijmegen, Nijmegen, The Netherlands
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25
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Blumkin L, Lev D, Watemberg N, Lerman-Sagie T. Hypomyelinating leukoencephalopathy with paroxysmal tonic upgaze and absence of psychomotor development. Mov Disord 2007; 22:226-30. [PMID: 17149740 DOI: 10.1002/mds.21277] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Hypomyelinating leukoencephalopathies are characterized by a substantial and permanent deficit in myelin deposition in the brain. Although our knowledge and understanding of the etiology of white matter diseases has progressively increased, many cases with this disorder remain undiagnosed, despite extensive evaluations. Recently, new disease entities have been defined by combining magnetic resonance imaging pattern recognition and clinical features. We describe a 1-year-old Ashkenazi Jewish girl with a hypomyelinating leukoencephalopathy, who presented in the neonatal period with episodes of sustained paroxysmal tonic upward gaze, roving eye movements, pendular nystagmus, and severe hypotonia, with the later appearance of pyramidal and extrapyramidal signs and no development. In addition, she has dysmorphic signs. This clinical picture is not consistent with any of the previously described hypomyelinating leukoencephalopathies and may represent a new entity.
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Affiliation(s)
- Lubov Blumkin
- Pediatric Neurology Unit, Wolfson Medical Center, Holon, affiliated to Sackler School of Medicine, Tel-Aviv University, Tel-Aviv, Israel
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26
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Vaurs-Barriere C, Bonnet-Dupeyron MN, Combes P, Gauthier-Barichard F, Reveles XT, Schiffmann R, Bertini E, Rodriguez D, Vago P, Armour JAL, Saugier-Veber P, Frebourg T, Leach RJ, Boespflug-Tanguy O. Golli-MBP copy number analysis by FISH, QMPSF and MAPH in 195 patients with hypomyelinating leukodystrophies. Ann Hum Genet 2006; 70:66-77. [PMID: 16441258 DOI: 10.1111/j.1529-8817.2005.00208.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The inherited disorders of CNS myelin formation represent a heterogeneous group of leukodystrophies. The proteolipoprotein (PLP1) gene has been implicated in two X-linked forms, Pelizaeus-Merzbacher disease (PMD) and spastic paraplegia type 2, and the gap junction protein alpha12 (GJA12) gene in a recessive form of PMD. The myelin basic protein (MBP) gene, which encodes the second most abundant CNS myelin protein after PLP1, presents rearrangements in hypomyelinating murine mutants and is always included in the minimal region deleted in 18q- patients with an abnormal hypomyelination pattern on cerebral MRI. In this study, we looked at the genomic copy number at the Golli-MBP locus in 195 patients with cerebral MRI suggesting a myelin defect, who do not have PLP1 mutation. Although preliminary results obtained by FISH suggested the duplication of Golli-MBP in 3 out of 10 patients, no abnormal gene quantification was found using Quantitative Multiplex PCR of Short Fluorescent fragments (QMPSF), Multiplex Amplifiable Probe Hybridization (MAPH), or another FISH protocol using directly-labelled probes. Pitfalls and interest in these different techniques to detect duplication events are emphasised. Finally, the study of this large cohort of patients suggests that Golli-MBP deletion or duplication is rarely involved in inherited defects of myelin formation.
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Affiliation(s)
- C Vaurs-Barriere
- INSERM U 384, Faculté de Médecine, Place Henri Dunant, 63000 Clermont-Ferrand, France
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27
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Netzer C, Helmstaedter C, Ehrbrecht A, Engels H, Schwanitz G, Urbach H, Schröder R, Weber RG, Kornblum C. Global brain dysmyelination with above-average verbal skills in 18q- syndrome with a 17 Mb terminal deletion. Acta Neurol Scand 2006; 114:133-8. [PMID: 16867037 DOI: 10.1111/j.1600-0404.2006.00626.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
BACKGROUND Patients with the karyotypic finding of a terminal deletion in the long arm of chromosome 18 (18q- syndrome) commonly display cerebral dysmyelination and developmental delay. To our knowledge, all reported cases characterized by molecular analysis who had no mental retardation as confirmed by neuropsychological testing had a chromosomal breakpoint within the two most distal bands, 18q22 or 18q23, leading to a deletion of 16 Mb or less. AIMS OF THE STUDY It was the aim of this study to improve the karyotype-phenotype correlation in 18q- syndrome by thoroughly analyzing the deletion size and the mental and radiologic status in a 23-year-old woman with a terminal 18q deletion. We performed cytogenetic and molecular cytogenetic analysis, brain MRI, and extended neuropsychological testing. RESULTS Molecular karyotyping revealed a 17 Mb deletion of terminal 18q with a breakpoint in 18q21.33 and no evidence for mosaicism. While brain MRI demonstrated severe global dysmyelination, the patient showed a neuropsychological pattern that allowed for normal psychosocial and job achievement. After delayed development in childhood, the patient caught up during puberty and showed normal verbal intelligence and skills at 23 years. However, visual, visual-spatial, visual-constructional, and executive functions were found to be severely impaired. CONCLUSION Here, we present a patient with one of the largest terminal 18q deletions reported in an individual without obvious mental retardation. Our analysis extends the phenotypic spectrum for individuals with breakpoints in 18q21.33. In addition, this study highlights the fact that severe global dysmyelination may not be associated with general cognitive deficits.
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Affiliation(s)
- C Netzer
- Institute of Human Genetics, Rheinische Friedrich-Wilhelms-University, Bonn, Germany.
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28
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Abstract
The leukodystrophies comprise an ever-expanding group of rare central nervous system disorders with defined clinical, pathological, and genetic characteristics. The broader term, leukoencephalopathy, is applied to all brain white matter diseases, whether their molecular cause is known. Magnetic resonance imaging has helped to elucidate new forms of leukodystrophy as well as to permit longitudinal studies of disease progression. The white matter abnormality may appear similar in different forms of leukodystrophy so that in most cases, further studies such as magnetic resonance spectroscopy, tissue biopsies, enzyme studies, and molecular DNA analyses are needed to pinpoint the specific diagnosis. The primary inherited leukoencephalopathies include dysmyelinating, hypomyelinative, and vacuolating forms. Metabolic and vascular causes account for most of the secondary forms, but other inherited syndromes are recognized that have their onset in childhood or adult life and are characterized by distinctive clinical and neuropathologic features. This review discusses some of the mechanisms that have been proposed to explain deficiencies of myelin and the molecular genetic bases underlying these disorders.
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Affiliation(s)
- Gilles Lyon
- Department of Child Neurology, University of Louvain School of Medicine, Brussels, Belgium
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29
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Abstract
Dys- and demyelination are the common endpoints of several inherited diseases of glial cells, which elaborate myelin and which maintain the myelin sheath very much like an "external" cellular organelle. Whereas some of the genes that are affected by mutations appear to be glial-specific, other genes are expressed in many cell types but their defect is restricted to oligodendrocytes or Schwann cells. Many of the disease genes and their encoded proteins have been studied with the help of mouse models, and a number of different molecular pathomechanisms have emerged which have been summarized in Figure 8. Some of the new concepts in the field, which have been addressed in this review, have only emerged because similar pathomechanisms were discovered for different myelin proteins. Mouse models have clearly helped to address both, the molecular pathology of myelin diseases and the normal function of myelin genes, but as discussed in this review, these questions turned out to be very different. Despite the progress in understanding the role of the abundant myelin proteins, there also remain a number of open questions that concern, among other things, the initial axon-glia recognition, the assembly process of the myelin sheath, and the long-term interaction of axons with their myelinating glia. Finally, animal models of human neurological diseases should not be restricted to the study of pathology, but they should also contribute to the development of experimental treatments. It is encouraging that a few attempts have been made.
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Affiliation(s)
- H Werner
- Zentrum für Molekulare Biologie (ZMBH), Universität Heidelberg, Germany
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30
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Dostal A, Nemeckova J, Gaillyova R, Vranova V, Zezulkova D, Lejska M, Slapak I, Dostalova Z, Kuglik P. Identification of 2.3-Mb Gene Locus for Congenital Aural Atresia in 18q22.3 Deletion. Otol Neurotol 2006; 27:427-32. [PMID: 16639285 DOI: 10.1097/00129492-200604000-00022] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE 18q deletion syndrome is a multiple-anomaly mental retardation syndrome associated with congenital aural atresia. The purpose of this study was to determine the frequency of the congenital aural atresia phenotype in 18q deletion syndrome patients and to delineate a potential critical region for congenital aural atresia at the 18q22.3-18q23 region. STUDY DESIGN AND PATIENTS The study describes one 18q deletion syndrome clinical report (Patient 15) with an overview of 19 other selected 18q deletion syndrome patients presenting congenital aural atresia from 18 published articles and one presented poster on 18q deletion syndrome. RESULTS Our investigation, together with the results of published 18q deletion syndrome reports, shows that the average frequency of congenital aural atresia is approximately 52%. A combination of three 18q deletion syndrome probands defines a chromosomal deletion site for congenital aural atresia at 18q22.3-18q23 in the region between markers D18S489 and D18S554. These polymorphic markers outline a putative critical interval of approximately 2.3 Mb, including the genes ZNF407, ZADH2, SDCCAG33, ZNF516, FLJ44881, ZNF236, MBP-Golli, and GALR1. The haploinsufficiency of these genes is suggested to be a primary cause of congenital aural atresia phenotype in 18q deletion syndrome individuals. CONCLUSION Congenital aural atresia is a relevant diagnostic clue and a major recognizable feature of 18q deletion syndrome. Early diagnosis of 18q deletion syndrome may enable application of hearing aids. Knockout studies on the congenital aural atresia mouse gene homolog may add further insight into the genes responsible for this condition.
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Affiliation(s)
- Ales Dostal
- Department of Pediatrics, University of Texas Health Science Center, San Antonio, Texas, USA, and Department of Medical Genetics, University Hospital Brno, Faculty of Science, Masaryk University, Brno, Czech Republic.
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Adab N, Larner AJ. Adult-onset seizure disorder in the 18q deletion syndrome. J Neurol 2006; 253:527-8. [PMID: 16541216 DOI: 10.1007/s00415-005-0009-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2005] [Revised: 05/24/2005] [Accepted: 05/25/2005] [Indexed: 11/25/2022]
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Linnankivi T, Tienari P, Somer M, Kähkönen M, Lönnqvist T, Valanne L, Pihko H. 18q deletions: Clinical, molecular, and brain MRI findings of 14 individuals. Am J Med Genet A 2006; 140:331-9. [PMID: 16419126 DOI: 10.1002/ajmg.a.31072] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
We studied 14 individuals with partial deletions of the long arm of chromosome 18, including terminal and interstitial de novo and inherited deletions. Study participants were examined clinically and by brain MRI. The size of the deletion was determined by segregation analysis using microsatellite markers. We observed that the phenotype was highly variable, even in two families with three 1st degree relatives. Among the 14 individuals, general intelligence varied from normal to severe mental retardation. The more common features of 18q-deletions (e.g., foot deformities, aural atresia, palatal abnormalities, dysmyelination, and nystagmus) were present in individuals lacking only the distal portion 18q22.3-qtel. Interstitial deletions exerted very heterogeneous effects on phenotype. In individuals with distal 18q22.3-q23 deletions, brain MRI was very distinctive with poor differentiation of gray and white matter on T2-weighted images.
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Affiliation(s)
- Tarja Linnankivi
- Department of Pediatric Neurology, Hospital for Children and Adolescents, University of Helsinki, Helsinki, Finland.
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Courtens W, Wuyts W, Scheers S, Van Luijk R, Reyniers E, Rooms L, Ceulemans B, Kooy F, Wauters J. A de novo subterminal trisomy 10p and monosomy 18q in a girl with MCA/MR: case report and review. Eur J Med Genet 2006; 49:402-13. [PMID: 16488200 DOI: 10.1016/j.ejmg.2006.01.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2005] [Accepted: 01/01/2006] [Indexed: 11/27/2022]
Abstract
We report on a 3-year-old girl with psychomotor retardation, cardiopathy, strabismus, umbilical hernia, and facial dysmorphism in whom a de novo unbalanced submicroscopic translocation (10p;18q) was found by MLPA (Multiplex Ligation dependent Probe Amplification) and FISH analyses. Additional FISH studies with locus specific RP11 BAC probes and analyses with microsatellites revealed that the translocation resulted in a deletion estimated between 6 and 9 Mb on the maternal chromosome 18 and a subtelomeric 10p duplication of approximately 6.9 Mb. The proband's karyotype is 46,XX.ish der(18) t(10;18)(18pter-->18q23:10p15 --> 10pter). A subterminal duplication of 10p, as well as a subterminal deletion of 18q have been rarely reported so far. The clinical phenotype of this patient is reviewed and discussed.
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Affiliation(s)
- Winnie Courtens
- Department of Medical Genetics, University Hospital Antwerp, Antwerp, Belgium.
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Turan S, Saka N, Guney I, Bereket A. A patient with hypopituitarism and isochromosome 18q mosaicism. HORMONE RESEARCH 2005; 64:261-5. [PMID: 16272819 DOI: 10.1159/000089424] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2005] [Accepted: 08/18/2005] [Indexed: 11/19/2022]
Abstract
AIMS Patients with isochromosome 18 [i(18q)] have features of both trisomy 18 and deletion of 18p [del(18p)] syndromes. Although, hypopituitarism has been reported in patients with del(18p) syndrome, it has not been described in patients with i(18q) syndrome previously. We describe a case with i(18q)/del(18p) mosaicism associated with a novel finding of hypopituitarism. METHODS Clinical characteristics of the patient have been discussed in the light of the literature. RESULTS The patient had dysmorphic findings that are predominantly seen in del(18p) syndrome such as low nasal bridge, wide mouth, large ears, high forehead, hypopigmentation, upturned nostrils and hypopituitarism (TSH, ACTH, and GH deficiencies, and pituitary hypoplasia on magnetic resonance imaging). In addition, she also had upturning of upper lip and seizures, which are features of trisomy 18 syndrome. CONCLUSIONS In agreement with the previous clinical reports, this case further supports the presence of a factor, which is involved in pituitary development and/or function, on the short arm of chromosome 18.
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Affiliation(s)
- Serap Turan
- Department of Paediatric Endocrinology, Marmara University Faculty of Medicine, Istanbul, Turkey
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35
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Hwang KS, Pearson MA, Stankiewicz P, Lennon PA, Cooper ML, Wu J, Ou Z, Cai WW, Patel A, Cheung SW. Cryptic unbalanced translocation t(17;18)(p13.2;q22.3) identified by subtelomeric FISH and defined by array-based comparative genomic hybridization in a patient with mental retardation and dysmorphic features. Am J Med Genet A 2005; 137:88-93. [PMID: 16015583 DOI: 10.1002/ajmg.a.30858] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Molecular cytogenetics allows the identification of cryptic chromosome rearrangements, which is clinically useful in mentally retarded and/or dysmorphic individuals with normal results from conventional cytogenetics analysis. We report on a 3-year-old girl with mental retardation, growth deficiency, speech delay, and dysmorphic features including hypertelorism, upslanting palpebral fissures, midfacial hypoplasia, and posteriorly rotated ears. The G-banding analysis showed a 46,XX,t(3;8)(q26.2;p21.1)mat karyotype. However, her clinical features were suggestive of the 18q syndrome. Subtelomeric FISH analysis revealed a der(18) translocated material from chromosome 17. Array-based comparative genomic hybridization (array-CGH) with subtelomeric BAC and PAC clones confirmed the abnormality and refined the breakpoints to 18q22.3-qter and 17p13.2-pter (deletion of 8.5 Mb and duplication of 3.9 Mb, respectively). This case demonstrates the diagnostic utility of combining conventional cytogenetics with molecular chromosome analyses for the identification of subtle chromosome abnormalities.
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MESH Headings
- Abnormalities, Multiple/genetics
- Abnormalities, Multiple/pathology
- Child, Preschool
- Chromosome Banding
- Chromosomes, Human, Pair 17/genetics
- Chromosomes, Human, Pair 18/genetics
- Face/abnormalities
- Female
- Genome, Human
- Humans
- In Situ Hybridization, Fluorescence/methods
- Intellectual Disability/pathology
- Karyotyping
- Nucleic Acid Hybridization/methods
- Syndrome
- Telomere/genetics
- Translocation, Genetic
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Affiliation(s)
- Kwei Shuai Hwang
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
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36
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Kochunov P, Lancaster J, Hardies J, Thompson PM, Woods RP, Cody JD, Hale DE, Laird A, Fox PT. Mapping structural differences of the corpus callosum in individuals with 18q deletions using targetless regional spatial normalization. Hum Brain Mapp 2005; 24:325-31. [PMID: 15704090 PMCID: PMC6871744 DOI: 10.1002/hbm.20090] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
Individuals with a constitutional chromosome abnormality consisting of a deletion of a portion of the long arm of chromosome 18 (18q-) have a high incidence ( approximately 95%) of dysmyelination. Neuroradiologic findings in affected children report a smaller corpus callosum, but this finding has not been quantified. This is in part due to the large intersubject variability of the corpus callosum size and shape and the small number of subjects with 18q-, which leads to low statistical power for comparison with typically developing children. An analysis method called targetless spatial normalization (TSN) was used to improve the sensitivity of statistical testing. TSN converges all images in a group into what is referred as group common space. The group common space conserves common shape, size, and orientation while reducing intragroup variability. TSN in conjunction with a Witelson vertical partitioning scheme was used to assess differences in corpus callosum size between 12 children with 18q- and 12 age-matched normal controls. Significant global and regional differences in corpus callosum size were seen. The 18q- group showed an overall smaller (25%) corpus callosum (P < 10(-7)), even after correction for differences in brain size. Regionally, the posterior portions of corpus callosum (posterior midbody, isthmus, and splenium), which contain heavily myelinated fibers, were found to be 25% smaller in the population with 18q-.
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Affiliation(s)
- Peter Kochunov
- Research Imaging Center, University of Texas Health Science Center at San Antonio, San Antonio, Texas, USA.
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37
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Grosso S, Pucci L, Di Bartolo RM, Gobbi G, Bartalini G, Anichini C, Scarinci R, Balestri M, Farnetani MA, Cioni M, Morgese G, Balestri P. Chromosome 18 aberrations and epilepsy: a review. Am J Med Genet A 2005; 134A:88-94. [PMID: 15690352 DOI: 10.1002/ajmg.a.30575] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Epilepsy is commonly observed in patients with chromosomal aberrations. We evaluated epilepsy and electroencephalographic (EEG) features in a group of patients carrying aberrations of chromosome 18. Fourteen patients were recruited: five with an 18p deletion syndrome (18pDS); six with an 18q deletion syndrome (18qDS); two with trisomy 18p syndrome; and one with a 45,XY,t(17-18) (cen-q11.2) karyotype. Patients with 18pDS had neither epilepsy nor EEG anomalies; four patients with 18qDS had epilepsy with partial seizures occurring during infancy or early childhood. Partial seizures were also present in both patients with trisomy 18p. By contrast, mixed seizures were observed in the patient carrying a translocation between chromosomes 17 and 18. Our data and a re-evaluation of the literature suggest that epilepsy is infrequent in patients with 18pDS. Conversely, partial seizures and focal EEG anomalies may be observed in those with patients with 18qDS. Our observations suggest that the haplo-insufficiency of genes located on the long arm of chromosome 18 is more likely to be associated with epilepsy, than is haplo-insufficiency of genes located on the short arm. While further EEG/clinical investigations are needed to validate these observations, this study indicates a possible relationship between chromosome 18 genes and epilepsy.
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Affiliation(s)
- S Grosso
- Department of Pediatrics, University of Siena, Siena, Italy
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38
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Schaub RL, Hale DE, Rose SR, Leach RJ, Cody JD. The spectrum of thyroid abnormalities in individuals with 18q deletions. J Clin Endocrinol Metab 2005; 90:2259-63. [PMID: 15671099 DOI: 10.1210/jc.2004-1630] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Chromosome 18q deletions (18q-) are survivable autosomal deletions, having an estimated incidence of one in 40,000 live births. Our long-term goals were to 1) comprehensively define the endocrine phenotype, 2) determine the natural history, and 3) identify key genes leading to particular phenotypes. This report specifically emphasizes the thyroid phenotype. Medical record review and comprehensive clinical assessment(s) were performed on 120 individuals with 18q- at the Chromosome 18 Clinical Research Center, the largest group of individuals with 18q- ever assembled. Affected subjects ranged in age from 6 wk to 32 yr at initial assessment. Due to case reports of thyroid dysfunction in 18q deletions and the well-established association between hypothyroidism and aneusomies, we undertook thyroid testing in all individuals and completed TRH studies on 50 of them. Our studies demonstrated that 12% had hypothyroidism, and the results were consistent with primary thyroidal dysfunction. Furthermore, two individuals progressed from normal to abnormal over the course of 2 yr. Based on these studies, it appears that, as is the case in other aneusomies, annual thyroid testing, using TSH as a primary screening tool, is indicated. The mechanism of the hypothyroidism is not yet known, and the genetic basis has not been delineated.
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Affiliation(s)
- Rebecca L Schaub
- Department of Pediatrics, University of Texas Health Science Center, 7703 Floyd Curl Drive, San Antonio, Texas 78229, USA
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39
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Delicado A, Lapunzina P, Palomares M, Molina MA, Galán E, López Pajares I. Beckwith-Wiedemann syndrome due to 11p15.5 paternal duplication associated with Klinefelter syndrome and a "de novo" pericentric inversion of chromosome Y. Eur J Med Genet 2005; 48:159-66. [PMID: 16053907 DOI: 10.1016/j.ejmg.2005.01.017] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We report on an infant who had been prenatally diagnosed with Klinefelter syndrome associated with a "de novo" pericentric inversion of the Y chromosome. A re-evaluation at 3 years of age suggested that he was also affected by Beckwith-Wiedemann syndrome (BWS). Karyotype was repeated and fluorescence in situ hybridisation (FISH) analysis revealed trisomy for 11p15.5-->11pter and a distal monosomy 18q (18q23-->qter). Parental cytogenetic studies showed that the father carried a balanced cryptic translocation between chromosomes 11p and 18q. Furthermore, the child had an extra X chromosome and a "de novo" structural abnormality of chromosome Y. Thus, his karyotype was 47,XX, inv (Y) (p11.2 q11.23), der(18) t (11;18) (p15.5;q23) pat. ish der(18) (D11S2071+, D18S1390-). Two markers on the X chromosome showed that the extra X of the child was paternally inherited. No deletions were observed on the structurally abnormal Y chromosome from any of the microsatellites studied. Clinical findings of patients with BWS due to partial trisomy 11p reveal that there is a distinct pattern of dysmorphic features associated with an increased incidence of mental retardation when comparing patients with normal chromosomes. This fact reinforces that FISH study have to be performed in all BWS patients, specially in those with mental retardation since small rearrangements cannot be detected by conventional cytogenetic techniques.
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MESH Headings
- Aneuploidy
- Beckwith-Wiedemann Syndrome/complications
- Beckwith-Wiedemann Syndrome/genetics
- Child, Preschool
- Chromosome Deletion
- Chromosome Inversion
- Chromosomes, Human, Pair 11/genetics
- Chromosomes, Human, Pair 18/genetics
- Chromosomes, Human, X/genetics
- Chromosomes, Human, Y/genetics
- Genetic Markers
- Humans
- In Situ Hybridization, Fluorescence
- Intellectual Disability/genetics
- Karyotyping
- Klinefelter Syndrome/complications
- Klinefelter Syndrome/genetics
- Male
- Phenotype
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Affiliation(s)
- Alicia Delicado
- Department of Genetics, Hospital Universitario La Paz, Madrid, Spain.
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40
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Häusler M, Anhuf D, Schüler H, Ramaekers VT, Thron A, Zerres K, Möller-Hartmann W. White-matter disease in 18q deletion (18q?) syndrome: magnetic resonance spectroscopy indicates demyelination or increased myelin turnover rather than dysmyelination. Neuroradiology 2005; 47:83-6. [PMID: 15645149 DOI: 10.1007/s00234-004-1309-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2004] [Accepted: 08/24/2004] [Indexed: 10/25/2022]
Abstract
Proton magnetic resonance spectroscopic data ((1)H-MR spectroscopy) of patients with 18q deletion syndrome have not yet been reported. (1)H-MR spectroscopy, performed in an affected 2-year-old girl with markedly delayed neuromotor development and typical supratentorial white-matter disease (WMD), showed an increase of choline and alpha-glutamate concentrations. Eight months later, simultaneously with clinical improvement, alpha-glutamate had normalised whereas choline remained slightly increased. Active demyelination or increased myelin turnover might contribute to the hitherto unexplained WMD of this rare disorder.
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Affiliation(s)
- M Häusler
- Department of Pediatrics, University Hospital of Aachen, Pauwelsstrasse 30, 52074 Aachen, Germany.
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41
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Cody JD, Semrud-Clikeman M, Hardies LJ, Lancaster J, Ghidoni PD, Schaub RL, Thompson NM, Wells L, Cornell JE, Love TM, Fox PT, Leach RJ, Kaye CI, Hale DE. Growth hormone benefits children with 18q deletions. Am J Med Genet A 2005; 137:9-15. [PMID: 16007630 DOI: 10.1002/ajmg.a.30848] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Most individuals with constitutional deletions of chromosome 18q have developmental delays, dysmyelination of the brain, and growth failure due to growth hormone deficiency. We monitored the effects of growth hormone treatment by evaluating 23 individuals for changes in growth, nonverbal intelligence quotient (nIQ), and quantitative brain MRI changes. Over an average of 37 months, the treated group of 13 children had an average nIQ increase of 17 points, an increase in height standard deviation score of 1.7, and significant change in T1 relaxation times in the caudate and frontal white matter. Cognitive changes of this magnitude are clinically significant and are anticipated to have an effect on the long-term outcomes for the treated individuals.
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Affiliation(s)
- Jannine D Cody
- Department of Pediatrics, University of Texas Health Science Center, San Antonio, 78229, USA.
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42
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Di Rocco M, Biancheri R, Rossi A, Filocamo M, Tortori-Donati P. Genetic disorders affecting white matter in the pediatric age. Am J Med Genet B Neuropsychiatr Genet 2004; 129B:85-93. [PMID: 15274047 DOI: 10.1002/ajmg.b.30029] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Pediatric white matter disorders can be distinguished into well-defined leukoencephalopathies, and undefined leukoencephalopathies. The first category may be subdivided into: (a) hypomyelinating disorders; (b) dysmyelinating disorders; (c) leukodystrophies; (d) disorders related to cystic degeneration of myelin; and (e) disorders secondary to axonal damage. The second category, representing up to 50% of leukoencephalopathies in childhood, requires a multidisciplinar approach in order to define novel homogeneous subgroups of patients, possibly representing "new genetic disorders" (such as megalencephalic leukoencepahlopathy with subcortical cysts and vanishing white matter disease that have recently been identified). In the majority of cases, pediatric white matter disorders are inherited diseases. An integrated description of the clinical, neuroimaging and pathophysiological features is crucial for categorizing myelin disorders and better understanding their genetic basis. A review of the genetic disorders affecting white matter in the pediatric age, including some novel entities, is provided.
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Affiliation(s)
- Maja Di Rocco
- Second Unit of Pediatrics, Istituto G. Gaslini, Genova, Italy.
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43
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Abernethy LJ, Klafkowski G, Foulder-Hughes L, Cooke RWI. Magnetic resonance imaging and T2 relaxometry of cerebral white matter and hippocampus in children born preterm. Pediatr Res 2003; 54:868-74. [PMID: 12930906 DOI: 10.1203/01.pdr.0000091285.84577.4e] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The objective of this study was to determine whether intelligence and minor motor impairments in children who are born preterm without major disability are associated with cerebral white matter (CWM) and hippocampal abnormalities on magnetic resonance imaging (MRI). A total of 103 preterm children were studied at age 7 y with detailed magnetic resonance brain scans, including a T2-mapping sequence from which T2 relaxation times of the CWM and hippocampal formations were calculated. All of the children had no major motor disability, attended normal school, and had undergone assessment of IQ and a test for minor motor impairment (MMI). Twenty children had visible lesions on MRI, which were associated with lower IQ and more frequent MMI. Mean (SD) IQ was 90 (14.1). Twenty-five children were shown to have MMI (Movement ABC at below the fifth centile). This group was shown to have significantly longer T2 relaxation times for CWM (mean difference 2.1 ms right, 3.1 ms left) but not the hippocampus than the children without MMI. These differences persisted when only children without visible lesions on scans were considered (mean difference 1.5 ms bilaterally). There was no significant correlation between IQ and T2 relaxation times. Children who are born preterm without subsequent major neurodisability may, in addition to visible lesions on MRI scans, have a diffuse abnormality of CWM, manifest as an increase in T2 relaxation time. This abnormality shows a close correlation with minor motor impairment but not with full-scale IQ.
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Affiliation(s)
- Laurence J Abernethy
- Department of Radiology, Royal Liverpool Children's Hospital, Liverpool L12 2AP, UK.
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44
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Linnankivi TT, Autti TH, Pihko SH, Somer MS, Tienari PJ, Wirtavuori KO, Valanne LK. 18q? Syndrome: Brain MRI shows poor differentiation of gray and white matter on T2-weighted images. J Magn Reson Imaging 2003; 18:414-9. [PMID: 14508777 DOI: 10.1002/jmri.10383] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
PURPOSE To study brain MRI findings in patients with 18q- syndrome and to correlate these findings with the results of the molecular breakpoint analysis. MATERIALS AND METHODS Brain MR images of 17 patients with 18q- syndrome were evaluated. Segregation analysis was performed with 15 microsatellite markers to determine the deletion breakpoints and whether the deletion included the myelin basic protein (MBP) gene. RESULTS One patient had an interstitial deletion of 18q which spared the MBP gene. He was the only one with normal brain MRI. All 16 patients with deletions including the MBP gene had abnormal white matter in MRI. The main finding was poor differentiation of gray and white matter on T2-weighted images due to increased white matter signal intensity. In addition, measured signal intensity of the white matter was significantly increased in patients compared with controls. CONCLUSIONS Poor differentiation of gray and white matter on T2-weighted images is the most typical MRI finding of the 18q- syndrome. These results support the postulation that abnormal myelination in 18q- syndrome is due to haploinsufficiency at or near the MBP locus.
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Affiliation(s)
- Tarja T Linnankivi
- Department of Pediatric Neurology, Hospital for Children and Adolescents, University of Helsinki, Helsinki, Finland.
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45
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Gunn SR, Mohammed M, Reveles XT, Viskochil DH, Palumbos JC, Johnson-Pais TL, Hale DE, Lancaster JL, Hardies LJ, Boespflug-Tanguy O, Cody JD, Leach RJ. Molecular characterization of a patient with central nervous system dysmyelination and cryptic unbalanced translocation between chromosomes 4q and 18q. Am J Med Genet A 2003; 120A:127-35. [PMID: 12794705 DOI: 10.1002/ajmg.a.20026] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
We report on a 12-year-old boy who presented with delayed development and CNS dysmyelination. Genetic studies showed a normal 46,XY karyotype by routine cytogenetic analysis, and 46,XY.ish del(18)(q23)(D18Z1+, MBP-) by FISH using a locus-specific probe for the MBP gene (18q23). Though the patient appeared to have normal chromosome 18s by repeated high resolution banding analysis, his clinical features were suggestive of a deletion of 18q. These included hearing loss secondary to stenosis of the external auditory canals, abnormal facial features, and foot deformities. FISH studies with genomic probes from 18q22.3 to 18qter confirmed a cryptic deletion which encompassed the MBP gene. In an attempt to further characterize the deletion, whole genome screening was conducted using array based comparative genomic hybridization (array CGH) analysis. The array CGH data not only confirmed a cryptic deletion in the 18q22.3 to 18qter region of approximately 7 Mb, it also showed a previously undetected 3.7 Mb gain of 4q material. FISH studies demonstrated that the gained 4q material was translocated distal to the 18qter deletion breakpoint. The 18q deletion contains, in addition to MBP, other known genes including CYB5, ZNF236, GALR1, and NFATC1, while the gained 4q material includes the genes FACL1 and 2, KLKB1, F11 and MTNR1A. The use of these combined methodologies has resulted in the first reported case in which array CGH has been used to characterize a congenital chromosomal abnormality, highlighting the need for innovative molecular cytogenetic techniques in the diagnosis of patients with idiopathic neurological abnormalities.
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Affiliation(s)
- Shelly R Gunn
- Department of Cellular and Structural Biology, The University of Texas Health Science Center, 7703 Floyd Curl Drive, San Antonio, TX 78229, USA.
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46
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Lancaster JL, Andrews T, Hardies LJ, Dodd S, Fox PT. Three-pool model of white matter. J Magn Reson Imaging 2003; 17:1-10. [PMID: 12500269 DOI: 10.1002/jmri.10230] [Citation(s) in RCA: 104] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
PURPOSE To investigate the use of a three-pool relaxation model to measure myelin, myelinated-axon, and mixed water-pool fractions in white matter (WM) during myelination. MATERIALS AND METHODS MRI at 1.9 Tesla, and conventional spin-echo imaging were used to acquire T1 and T2 relaxation data in 15 normal children ranging in age from 3 months to 13 years 4 months. Three equations with three unknowns were solved to calculate three water-pool fractions for each child in a frontal association-fiber area and a frontal-parietal projection-fiber area. The temporal trend of the fractions was compared with a theoretical three-pool myelination model. RESULTS The myelin level in the projection-fiber area rose earlier than in the association-fiber area following the standard caudal-to-rostral trend. The temporal trend of the three-pool fractions followed that predicted by the theoretical myelination model in both brain areas. The myelinated-axon and mixed pool sizes were significantly different in the two WM areas following early myelination, although their myelin pools were similar. T1 values correlated more highly with the myelinated-axon and mixed pool fractions than with the myelin pool fraction. CONCLUSION The three-pool relaxation model provides measurements of water-pool fractions in WM that follow values predicted during myelination.
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Affiliation(s)
- Jack L Lancaster
- University of Texas Health Science Center at San Antonio, Research Imaging Center, San Antonio, Texas 78284, USA.
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47
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Lehman DM, Harrison JM. Flash visual evoked potentials in the hypomyelinated mutant mouse shiverer. Doc Ophthalmol 2002; 104:83-95. [PMID: 11949811 DOI: 10.1023/a:1014415313818] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Myelin basic protein (MBP) is an essential component of central nervous system (CNS) myelin, as demonstrated by shiverer mutant mice that have deletions of most of the Mbp structural gene. These mutants do not produce detectable MBP protein, and their CNS is hypomyelinated. Although the function of the visual pathway is presumed to be adversely affected by hypomyelination of the optic nerve, it has never been studied. We compared flash visual evoked potentials (FVEPs) of shiverer homozygotes with those of their wild-type littermates in order to characterize any dysfunction. There was a statistically significant delay in the implicit times of a negative component peaking at 85 ms and a large positive component peaking at 170 ms in the FVEPs of the shiverer mice. The amplitudes of the two components did not differ significantly in the shiverers and wild-type controls. Barring a retinal pathology, which cannot be excluded by these data, the delayed FVEP of the shiverer can likely be attributed to effects of hypomyelination of the optic nerve, optic tract and visual radiations on conduction time in the visual pathway and subsequent further post-synaptic delays.
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Affiliation(s)
- Donna M Lehman
- Department of Ophthalmology, The University of Texas Health Science Center, San Antonio 78229-3900, USA
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48
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Abstract
This review centers on important recent advances in the understanding of the role of glial fibrillary acidic protein in Alexander disease and of proteolipid protein in hypomyelinating disorders such as Pelizaeus-Merzbacher and spastic paraplegia. We also describe seven novel leukodystrophies. These include childhood ataxia with central nervous system hypomyelination, a relatively common leukodystrophy syndrome with linkage to chromosome 3 in some patients, and megalencephalic leukoencephalopathy with subcortical cysts whose gene has recently been cloned. These, along with five other disorders, including leukodystrophy with polyol metabolism abnormality, demonstrate that an increasing number of protein and metabolic abnormalities can cause primary myelin disorders.
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Affiliation(s)
- R Schiffmann
- National Institutes of Health, Building 10, Room 3D03, 9000 Rockville Pike, Bethesda, MD 20892-1260, USA.
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49
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Stankiewicz P, Brozek I, Hélias-Rodzewicz Z, Wierzba J, Pilch J, Bocian E, Balcerska A, Wozniak A, Kardaś I, Wirth J, Mazurczak T, Limon J. Clinical and molecular-cytogenetic studies in seven patients with ring chromosome 18. AMERICAN JOURNAL OF MEDICAL GENETICS 2001; 101:226-39. [PMID: 11424138 DOI: 10.1002/1096-8628(20010701)101:3<226::aid-ajmg1349>3.0.co;2-#] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
We report the results of detailed clinical and molecular-cytogenetic studies in seven patients with ring chromosome 18. Classical cytogenetics and fluorescence in situ hybridization (FISH) analysis with the chromosome 18 painting probe identified five non-mosaic and two complex mosaic 46,XX,dup(18)(p11.2)/47,XX,dup(18)(p11.2),+r(18) and 46,XX,dup(18)(p11.32)/47,XX,dup(18)(p11.32),+r(18) cases. FISH analysis was performed for precise characterization of the chromosome 18 breakpoints using chromosome 18-specific short-arm paint, centromeric, subtelomeric, and a panel of fifteen Alu- and DOP-PCR YAC probes. The breakpoints were assessed with an average resolution of approximately 2.2 Mb. In all r(18) chromosomes, the 18q terminal deletions ranging from 18q21.2 to 18q22.3 ( approximately 35 and 9 Mb, respectively) were found, whereas only in four cases could the loss of 18p material be demonstrated. In two cases the dup(18) chromosomes were identified as inv dup(18)(qter-->p11.32::q21.3-->qter) and inv dup(18)(qter-->p11.32::p11.32-->p11.1: :q21.3-->qter)pat, with no evidence of an 18p deletion. A novel inter-intrachromatid mechanism of formation of duplications and ring chromosomes is proposed. Although the effect of "ring instability syndrome" cannot be excluded, the phenotypes of our patients with characteristic features of 18q- and 18p- syndromes are compared and correlated with the analyzed genotypes. It has been observed that a short neck with absence of cardiac anomalies may be related to the deletion of the 18p material from the r(18) chromosome.
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Affiliation(s)
- P Stankiewicz
- Department of Medical Genetics, Institute of Mother and Child, Warsaw, Poland.
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50
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Baumann N, Pham-Dinh D. Biology of oligodendrocyte and myelin in the mammalian central nervous system. Physiol Rev 2001; 81:871-927. [PMID: 11274346 DOI: 10.1152/physrev.2001.81.2.871] [Citation(s) in RCA: 1203] [Impact Index Per Article: 52.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Oligodendrocytes, the myelin-forming cells of the central nervous system (CNS), and astrocytes constitute macroglia. This review deals with the recent progress related to the origin and differentiation of the oligodendrocytes, their relationships to other neural cells, and functional neuroglial interactions under physiological conditions and in demyelinating diseases. One of the problems in studies of the CNS is to find components, i.e., markers, for the identification of the different cells, in intact tissues or cultures. In recent years, specific biochemical, immunological, and molecular markers have been identified. Many components specific to differentiating oligodendrocytes and to myelin are now available to aid their study. Transgenic mice and spontaneous mutants have led to a better understanding of the targets of specific dys- or demyelinating diseases. The best examples are the studies concerning the effects of the mutations affecting the most abundant protein in the central nervous myelin, the proteolipid protein, which lead to dysmyelinating diseases in animals and human (jimpy mutation and Pelizaeus-Merzbacher disease or spastic paraplegia, respectively). Oligodendrocytes, as astrocytes, are able to respond to changes in the cellular and extracellular environment, possibly in relation to a glial network. There is also a remarkable plasticity of the oligodendrocyte lineage, even in the adult with a certain potentiality for myelin repair after experimental demyelination or human diseases.
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Affiliation(s)
- N Baumann
- Institut National de la Santé et de la Recherche Médicale U. 495, Biology of Neuron-Glia Interactions, Salpêtrière Hospital, Paris, France.
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