1
|
Ahmad E, Ali A, Nimisha, Kumar Sharma A, Ahmed F, Mehdi Dar G, Mohan Singh A, Apurva, Kumar A, Athar A, Parveen F, Mahajan B, Singh Saluja S. Molecular approaches in cancer. Clin Chim Acta 2022; 537:60-73. [DOI: https:/doi.org/10.1016/j.cca.2022.09.027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/28/2023]
|
2
|
Ahmad E, Ali A, Nimisha, Kumar Sharma A, Ahmed F, Mehdi Dar G, Mohan Singh A, Apurva, Kumar A, Athar A, Parveen F, Mahajan B, Singh Saluja S. Molecular approaches in cancer. Clin Chim Acta 2022; 537:60-73. [DOI: 10.1016/j.cca.2022.09.027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Revised: 09/28/2022] [Accepted: 09/28/2022] [Indexed: 11/03/2022]
|
3
|
Altıner Ş, Yürür Kutlay N. Importance of patient selection criteria in determining diagnostic copy number variations in patients with multiple congenital anomaly/mental retardation. Mol Cytogenet 2019; 12:23. [PMID: 31149029 PMCID: PMC6537423 DOI: 10.1186/s13039-019-0436-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Accepted: 05/17/2019] [Indexed: 11/10/2022] Open
Abstract
Background Etiology of developmental delay/intellectual disability is very heterogeneous. In recent years, genetic causes have been defined through the use of chromosomal microarray analysis as a first step genetic test. Results Samples from 30 patients with multiple congenital anomaly and/or mental retardation were analyzed with array comparative genomic hybridization in the context of this study. Before this analysis, karyotyping, subtelomeric fluorescence in situ hybridization and additionally fragment analysis for fragile X in males, had been routinely made all of which were reported to be normal. The purpose of our study was to determine the copy number variations as well as to investigate methods to increase diagnostic yield of array comparative genomic hybridization and forming a suitable flow chart decision pipeline for test indication especially for developing countries. Genomic changes were identified at a rate of about 27% in our series. Although this ratio is higher than the literature data, it could be due to the patient selection criteria. Conclusion Chromosomal microarray analysis is not easily utilized for all patients because of its high-cost. Thus, for increasing cost-effectiveness, it may be used step by step for defined targets. Along with discussing the patients with copy number variations relevant with the phenotype, we suggest a flow chart for selection of diagnostic test with the highest diagnostic rate and the lowest expenditure which is quite important for developing countries.
Collapse
Affiliation(s)
- Şule Altıner
- Department of Medical Genetics, Trabzon Kanuni Training and Research Hospital, University of Health Sciences, Topal Osman Street 7, 61290 Trabzon, Turkey.,2Department of Medical Genetics, School of Medicine, Ankara University, Ankara, Turkey
| | - Nüket Yürür Kutlay
- 2Department of Medical Genetics, School of Medicine, Ankara University, Ankara, Turkey
| |
Collapse
|
4
|
Abstract
INTRODUCTION In 2004, the implementation of array comparative genomic hybridization (array comparative genome hybridization [CGH]) into clinical practice marked a new milestone for genetic diagnosis. Array CGH and single-nucleotide polymorphism (SNP) arrays enable genome-wide detection of copy number changes in a high resolution, and therefore microarray has been recognized as the first-tier test for patients with intellectual disability or multiple congenital anomalies, and has also been applied prenatally for detection of clinically relevant copy number variations in the fetus. Area covered: In this review, the authors summarize the evolution of array CGH technology from their diagnostic laboratory, highlighting exonic SNP arrays developed in the past decade which detect small intragenic copy number changes as well as large DNA segments for the region of heterozygosity. The applications of array CGH to human diseases with different modes of inheritance with the emphasis on autosomal recessive disorders are discussed. Expert commentary: An exonic array is a powerful and most efficient clinical tool in detecting genome wide small copy number variants in both dominant and recessive disorders. However, whole-genome sequencing may become the single integrated platform for detection of copy number changes, single-nucleotide changes as well as balanced chromosomal rearrangements in the near future.
Collapse
Affiliation(s)
- Sau W Cheung
- a Department of Molecular and Human Genetics , Baylor College of Medicine , Houston , TX , USA
| | - Weimin Bi
- a Department of Molecular and Human Genetics , Baylor College of Medicine , Houston , TX , USA.,b Baylor Genetics , Houston , TX , USA
| |
Collapse
|
5
|
De Rienzo F, Mellone S, Bellone S, Babu D, Fusco I, Prodam F, Petri A, Muniswamy R, De Luca F, Salerno M, Momigliano-Richardi P, Bona G, Giordano M. Frequency of genetic defects in combined pituitary hormone deficiency: a systematic review and analysis of a multicentre Italian cohort. Clin Endocrinol (Oxf) 2015; 83:849-60. [PMID: 26147833 DOI: 10.1111/cen.12849] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/16/2015] [Revised: 03/22/2015] [Accepted: 07/02/2015] [Indexed: 01/16/2023]
Abstract
OBJECTIVE Combined pituitary hormonal deficiency (CPHD) can result from mutations within genes that encode transcription factors. This study evaluated the frequency of mutations in these genes in a cohort of 144 unrelated Italian patients with CPHD and estimated the overall prevalence of mutations across different populations using a systematic literature review. MATERIAL AND METHODS A multicentre study of adult and paediatric patients with CPHD was performed. The PROP1, POU1F1, HESX1, LHX3 and LHX4 genes were analysed for the presence of mutations using direct sequencing. We systematically searched PubMed with no date restrictions for studies that reported genetic screening of CPHD cohorts. We only considered genetic screenings with at least 10 individuals. Data extraction was conducted in accordance with the guidelines set by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). RESULTS Global mutation frequency in Italian patients with CPHD was 2·9% (4/136) in sporadic cases and 12·5% (1/8) in familial cases. The worldwide mutation frequency for the five genes calculated from 21 studies was 12·4%, which ranged from 11·2% in sporadic to 63% in familial cases. PROP1 was the most frequently mutated gene in sporadic (6·7%) and familial cases (48·5%). CONCLUSION The frequency of defects in genes encoding pituitary transcription factors is quite low in Italian patients with CPHD and other western European countries, especially in sporadic patients. The decision of which genes should be tested and in which order should be guided by hormonal and imaging phenotype, the presence of extrapituitary abnormalities and the frequency of mutation for each gene in the patient-referring population.
Collapse
Affiliation(s)
- Francesca De Rienzo
- Unit of Paediatrics, Department of Health Sciences, University of Eastern Piedmont, Novara, Italy
| | - Simona Mellone
- Laboratory of Genetics, Department of Health Sciences, University of Eastern Piedmont and IRCAD, Novara, Italy
| | - Simonetta Bellone
- Unit of Paediatrics, Department of Health Sciences, University of Eastern Piedmont, Novara, Italy
| | - Deepak Babu
- Laboratory of Genetics, Department of Health Sciences, University of Eastern Piedmont and IRCAD, Novara, Italy
| | - Ileana Fusco
- Laboratory of Genetics, Department of Health Sciences, University of Eastern Piedmont and IRCAD, Novara, Italy
| | - Flavia Prodam
- Unit of Paediatrics, Department of Health Sciences, University of Eastern Piedmont, Novara, Italy
| | - Antonella Petri
- Unit of Paediatrics, Department of Health Sciences, University of Eastern Piedmont, Novara, Italy
| | - Ranjith Muniswamy
- Laboratory of Genetics, Department of Health Sciences, University of Eastern Piedmont and IRCAD, Novara, Italy
| | - Filippo De Luca
- Department of Paediatrics, University of Messina, Messina, Italy
| | - Mariacarolina Salerno
- Paediatric Section, Department of Translational Medical Sciences, Federico II University, Naples, Italy
| | | | - Gianni Bona
- Unit of Paediatrics, Department of Health Sciences, University of Eastern Piedmont, Novara, Italy
| | - Mara Giordano
- Laboratory of Genetics, Department of Health Sciences, University of Eastern Piedmont and IRCAD, Novara, Italy
| |
Collapse
|
6
|
Abstract
Molecular genetic testing involves DNA analysis using various methods for the purpose of diagnosing genetic disorders. In the prenatal DNA diagnostic setting, fetal DNA is usually tested for a specific single-gene disorder for which the fetal risk is 25% or more. In contrast, cytogenetic testing is often used to detect fetal chromosomal abnormalities in cases that involve a wider range of indications. Classic cytogenetic and DNA-based testing methods provide a range of aberrations detected with different levels of genomic resolution. More recently developed molecular cytogenetic methods provide powerful tools to bridge the technical divide between these related areas. One such hybrid method is microarray-based comparative genomic hybridization. Chromosomal microarray analysis has been applied to clinical testing for unbalanced gains or losses of genomic regions associated with genetic disorders. This technology is poised to have a substantial impact on clinical genetics, including prenatal genetic testing.
Collapse
Affiliation(s)
- Benjamin B Roa
- Department of Molecular & Human Genetics, Baylor College of Medicine, NAB2015, Houston, TX 77030, USA.
| | | | | | | |
Collapse
|
7
|
Møller RS, Jensen LR, Maas SM, Filmus J, Capurro M, Hansen C, Marcelis CLM, Ravn K, Andrieux J, Mathieu M, Kirchhoff M, Rødningen OK, de Leeuw N, Yntema HG, Froyen G, Vandewalle J, Ballon K, Klopocki E, Joss S, Tolmie J, Knegt AC, Lund AM, Hjalgrim H, Kuss AW, Tommerup N, Ullmann R, de Brouwer APM, Strømme P, Kjaergaard S, Tümer Z, Kleefstra T. X-linked congenital ptosis and associated intellectual disability, short stature, microcephaly, cleft palate, digital and genital abnormalities define novel Xq25q26 duplication syndrome. Hum Genet 2013; 133:625-38. [PMID: 24326587 DOI: 10.1007/s00439-013-1403-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2013] [Accepted: 11/21/2013] [Indexed: 12/12/2022]
Abstract
Submicroscopic duplications along the long arm of the X-chromosome with known phenotypic consequences are relatively rare events. The clinical features resulting from such duplications are various, though they often include intellectual disability, microcephaly, short stature, hypotonia, hypogonadism and feeding difficulties. Female carriers are often phenotypically normal or show a similar but milder phenotype, as in most cases the X-chromosome harbouring the duplication is subject to inactivation. Xq28, which includes MECP2 is the major locus for submicroscopic X-chromosome duplications, whereas duplications in Xq25 and Xq26 have been reported in only a few cases. Using genome-wide array platforms we identified overlapping interstitial Xq25q26 duplications ranging from 0.2 to 4.76 Mb in eight unrelated families with in total five affected males and seven affected females. All affected males shared a common phenotype with intrauterine- and postnatal growth retardation and feeding difficulties in childhood. Three had microcephaly and two out of five suffered from epilepsy. In addition, three males had a distinct facial appearance with congenital bilateral ptosis and large protruding ears and two of them showed a cleft palate. The affected females had various clinical symptoms similar to that of the males with congenital bilateral ptosis in three families as most remarkable feature. Comparison of the gene content of the individual duplications with the respective phenotypes suggested three critical regions with candidate genes (AIFM1, RAB33A, GPC3 and IGSF1) for the common phenotypes, including candidate loci for congenital bilateral ptosis, small head circumference, short stature, genital and digital defects.
Collapse
Affiliation(s)
- R S Møller
- Danish Epilepsy Centre, Dianalund, Kolonivej 7, 4293, Dianalund, Denmark,
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
8
|
Willemsen MH, de Leeuw N, de Brouwer AP, Pfundt R, Hehir-Kwa JY, Yntema HG, Nillesen WM, de Vries BB, van Bokhoven H, Kleefstra T. Interpretation of clinical relevance of X-chromosome copy number variations identified in a large cohort of individuals with cognitive disorders and/or congenital anomalies. Eur J Med Genet 2012; 55:586-98. [DOI: 10.1016/j.ejmg.2012.05.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2012] [Revised: 05/05/2012] [Accepted: 05/05/2012] [Indexed: 01/01/2023]
|
9
|
Perche O, Laudier B, Menuet A, Odent S, Laumonnier F, Briault S. FG syndrome: The FGS2 locus revisited. Am J Med Genet A 2012; 158A:1489-92. [DOI: 10.1002/ajmg.a.35322] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2011] [Accepted: 01/09/2012] [Indexed: 11/08/2022]
|
10
|
Gambardella S, Ciabattoni E, Motta F, Stoico G, Gullotta F, Biancolella M, Nardone AM, Novelli A, Brunetti E, Bernardini L, Novelli G. Design, Construction and Validation of Targeted BAC Array-Based CGH Test for Detecting the Most Commons Chromosomal Abnormalities. Genomics Insights 2010; 3:9-21. [PMID: 26279624 PMCID: PMC4510597 DOI: 10.4137/gei.s3683] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
We designed a targeted-array called GOLD (Gain or Loss Detection) Chip consisting of 900 FISH-mapped non-overlapping BAC clones spanning the whole genome to enhance the coverage of 66 unique human genomic regions involved in well known microdeletion/microduplication syndromes. The array has a 10 Mb backbone to guarantee the detection of the aneuploidies, and has an implemented resolution for telomeres, and for regions involved in common genomic diseases. In order to evaluate clinical diagnostic applicability of GOLDChip, analytical validity was carried-out via retrospective analysis of DNA isolated from a series of cytogenetically normal amniocytes and cytogenetically abnormal DNA obtained from cultured amniocytes, peripheral blood and/or cell lines. We recruited 47 DNA samples corresponding to pathologies with significant frequencies (Cri du Chat syndrome, Williams syndrome, Prader Willi/Angelman syndromes, Smith-Magenis syndrome, DiGeorge syndrome, Miller-Dieker syndrome, chromosomes 13, 18 and 21 trisomies). We set up an experimental protocol that allowed to identify chromosomal rearrangements in all the DNA samples analyzed. Our results provide evidence that our targeted BAC array can be used for the identification of the most common microdeletion syndromes and common aneuploidies.
Collapse
Affiliation(s)
- Stefano Gambardella
- Department of Biopathology, Tor Vergata University, Rome, Italy. ; Fondazione Livio Patrizi, Rome, Italy
| | | | | | - Giusy Stoico
- Technogenetics srl, Sesto San Giovanni, Milan, Italy
| | | | - Michela Biancolella
- Department of Biopathology, Tor Vergata University, Rome, Italy. ; Department of Preventive Medicine, Harlyne Norris Research Tower, University of Southern California, Los Angeles, CA
| | | | | | | | | | - Giuseppe Novelli
- Department of Biopathology, Tor Vergata University, Rome, Italy. ; Azienda Ospedaliera Universitaria Policlinico Tor Vergata, Rome, Italy. ; Fondazione Livio Patrizi, Rome, Italy
| |
Collapse
|
11
|
Bashiardes S, Kousoulidou L, van Bokhoven H, Ropers HH, Chelly J, Moraine C, de Brouwer APM, Van Esch H, Froyen G, Patsalis PC. A new chromosome x exon-specific microarray platform for screening of patients with X-linked disorders. J Mol Diagn 2009; 11:562-8. [PMID: 19779134 DOI: 10.2353/jmoldx.2009.090086] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Recent studies and advances in high-density oligonucleotide arrays have shown that microdeletions and microduplications occur at a high frequency in the human genome, causing various genetic conditions including mental retardation. Thus far little is known about the pathways leading to this disease, and implementation of microarrays is hampered by their increasing cost and complexity, underlining the need for new diagnostic tools. The aim of this study was to introduce a new targeted platform called "chromosome X exon-specific array" and to apply this new platform to screening of 20 families (including one blind positive control) with suspected X-linked mental retardation, to identify new causative X-linked mental retardation genes. The new microarray contains of 21,939 oligonucleotides covering 92.9% of all exons of all genes on chromosome X. Patient screening resulted in successful identification of the blind positive control included in the sample of 20 families, and one of the remaining 19 families was found to carry a 1.78-kilobase deletion involving all exons of pseudogene BRAF2. The BRAF2 deletion segregated in the family and was not found in 200 normal male samples, and no copy number variations are reported in this region. Further studies and focused investigation of X-linked disorders have the potential to reveal the molecular basis of human genetic pathological conditions that are caused by copy-number changes in chromosome X genes.
Collapse
Affiliation(s)
- Stavros Bashiardes
- Cyprus Institute of Neurology and Genetics, PO Box 23462, 1683 Nicosia, Cyprus
| | | | | | | | | | | | | | | | | | | |
Collapse
|
12
|
Carvalho CMB, Zhang F, Liu P, Patel A, Sahoo T, Bacino CA, Shaw C, Peacock S, Pursley A, Tavyev YJ, Ramocki MB, Nawara M, Obersztyn E, Vianna-Morgante AM, Stankiewicz P, Zoghbi HY, Cheung SW, Lupski JR. Complex rearrangements in patients with duplications of MECP2 can occur by fork stalling and template switching. Hum Mol Genet 2009; 18:2188-203. [PMID: 19324899 DOI: 10.1093/hmg/ddp151] [Citation(s) in RCA: 156] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Duplication at the Xq28 band including the MECP2 gene is one of the most common genomic rearrangements identified in neurodevelopmentally delayed males. Such duplications are non-recurrent and can be generated by a non-homologous end joining (NHEJ) mechanism. We investigated the potential mechanisms for MECP2 duplication and examined whether genomic architectural features may play a role in their origin using a custom designed 4-Mb tiling-path oligonucleotide array CGH assay. Each of the 30 patients analyzed showed a unique duplication varying in size from approximately 250 kb to approximately 2.6 Mb. Interestingly, in 77% of these non-recurrent duplications, the distal breakpoints grouped within a 215 kb genomic interval, located 47 kb telomeric to the MECP2 gene. The genomic architecture of this region contains both direct and inverted low-copy repeat (LCR) sequences; this same region undergoes polymorphic structural variation in the general population. Array CGH revealed complex rearrangements in eight patients; in six patients the duplication contained an embedded triplicated segment, and in the other two, stretches of non-duplicated sequences occurred within the duplicated region. Breakpoint junction sequencing was achieved in four duplications and identified an inversion in one patient, demonstrating further complexity. We propose that the presence of LCRs in the vicinity of the MECP2 gene may generate an unstable DNA structure that can induce DNA strand lesions, such as a collapsed fork, and facilitate a Fork Stalling and Template Switching event producing the complex rearrangements involving MECP2.
Collapse
Affiliation(s)
- Claudia M B Carvalho
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
13
|
Abstract
BACKGROUND Fluorescence in situ hybridization (FISH) has become a well-established method in medical diagnostics. FISH methods complement conventional cytogenetic banding techniques and offer extra clinical applications. FISH is based on the binding of complementary, single-stranded fluorescence-labeled nucleic acid sequences to the fixed and denatured target DNA of metaphases, interphase nuclei or isolated DNA sequences (BACs, oligonucleotides). OBJECTIVE The intent of this article is to review the development of molecular cytogenetic techniques available at present and to summarize the most efficient and appropriate use of these techniques in medical diagnostics. The technical aspects and most important applications of FISH assays are described. CONCLUSION FISH is bridging the gap between conventional cytogenetic banding analysis and molecular genetic DNA studies. The use of FISH techniques enhances the correct interpretation of numerical and structural chromosome aberrations.
Collapse
Affiliation(s)
- Markus Stumm
- Centre for Prenatal Diagnosis, Kudamm 199, Berlin 10719, Germany
| | | |
Collapse
|
14
|
Woldringh G, Janssen I, Hehir-Kwa J, van den Elzen C, Kremer J, de Boer P, Schoenmakers E. Constitutional DNA copy number changes in ICSI children. Hum Reprod 2008; 24:233-40. [DOI: 10.1093/humrep/den323] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
|
15
|
Chan P, Anguiano A, Hensley K, Keo N, Liu Y, Sarno R, Strom CM, Owen R. Clinical array comparative genomic hybridization: a new paradigm. Expert Opin Med Diagn 2008; 2:449-459. [PMID: 23495710 DOI: 10.1517/17530059.2.4.449] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
BACKGROUND Although the clinical utility of array comparative genomic hybridization (aCGH) is undisputed, the implementation of this technology is a unique experience for each laboratory. OBJECTIVE Endeavors to construct a bacterial artificial chromosome (BAC)-based CGH microarray targeting microdeletion and duplication syndromes related to mental retardation and developmental delay are described. METHOD Covering each chromosome at the 650-band level, the array comprises 1360 BAC clones with emphasis on the subtelomeric and pericentromeric regions and enrichment of genomic hot spots containing genes associated with specific constitutional disorders. During development of the array, fluorescence in situ hybridization (FISH) and end-sequencing analysis eliminated 24% of BACs that were mismapped or cross-hybridized, underscoring the need rigorously to assess arrayed elements. Performance of the BACs was tested further with chromosome-specific add-in experiments. CONCLUSION Of the first 500 clinical cases, 54 (11%) showed chromosome abnormalities, which were confirmed by FISH with BACs from the aberrant loci or by conventional cytogenetics. Array CGH is a powerful tool that is now being implemented in the realm of diagnostic testing.
Collapse
Affiliation(s)
- Patricia Chan
- Senior Scientist Quest Diagnostics Nichols Institute, Department of Cytogenetics, 33608 Ortega Highway San Juan Capistrano, CA 92675, USA +1 949 728 4805 ; +1 949 728 4979 ;
| | | | | | | | | | | | | | | |
Collapse
|
16
|
Madrigal I, Rodríguez-Revenga L, Armengol L, González E, Rodriguez B, Badenas C, Sánchez A, Martínez F, Guitart M, Fernández I, Arranz JA, Tejada M, Pérez-Jurado LA, Estivill X, Milà M. X-chromosome tiling path array detection of copy number variants in patients with chromosome X-linked mental retardation. BMC Genomics 2007; 8:443. [PMID: 18047645 DOI: 10.1186/1471-2164-8-443] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2007] [Accepted: 11/29/2007] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Aproximately 5-10% of cases of mental retardation in males are due to copy number variations (CNV) on the X chromosome. Novel technologies, such as array comparative genomic hybridization (aCGH), may help to uncover cryptic rearrangements in X-linked mental retardation (XLMR) patients. We have constructed an X-chromosome tiling path array using bacterial artificial chromosomes (BACs) and validated it using samples with cytogenetically defined copy number changes. We have studied 54 patients with idiopathic mental retardation and 20 controls subjects. RESULTS Known genomic aberrations were reliably detected on the array and eight novel submicroscopic imbalances, likely causative for the mental retardation (MR) phenotype, were detected. Putatively pathogenic rearrangements included three deletions and five duplications (ranging between 82 kb to one Mb), all but two affecting genes previously known to be responsible for XLMR. Additionally, we describe different CNV regions with significant different frequencies in XLMR and control subjects (44% vs. 20%). CONCLUSION This tiling path array of the human X chromosome has proven successful for the detection and characterization of known rearrangements and novel CNVs in XLMR patients.
Collapse
|
17
|
Kousoulidou L, Parkel S, Zilina O, Palta P, Puusepp H, Remm M, Turner G, Boyle J, van Bokhoven H, de Brouwer A, Van Esch H, Froyen G, Ropers HH, Chelly J, Moraine C, Gecz J, Kurg A, Patsalis PC. Screening of 20 patients with X-linked mental retardation using chromosome X-specific array-MAPH. Eur J Med Genet 2007; 50:399-410. [DOI: 10.1016/j.ejmg.2007.09.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2007] [Accepted: 09/23/2007] [Indexed: 02/04/2023]
|
18
|
Froyen G, Van Esch H, Bauters M, Hollanders K, Frints SGM, Vermeesch JR, Devriendt K, Fryns JP, Marynen P. Detection of genomic copy number changes in patients with idiopathic mental retardation by high-resolution X-array-CGH: important role for increased gene dosage of XLMR genes. Hum Mutat 2007; 28:1034-42. [PMID: 17546640 DOI: 10.1002/humu.20564] [Citation(s) in RCA: 146] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
A tiling X-chromosome-specific genomic array with a theoretical resolution of 80 kb was developed to screen patients with idiopathic mental retardation (MR) for submicroscopic copy number differences. Four patients with aberrations previously detected at lower resolution were first analyzed. This facilitated delineation of the location and extent of the aberration at high resolution and subsequently, more precise genotype-phenotype analyses. A cohort of 108 patients was screened, 57 of which were suspected of X-linked mental retardation (XLMR), 26 were probands of brother pairs, and 25 were sporadic cases. A total of 15 copy number changes in 14 patients (13%) were detected, which included two deletions and 13 duplications ranging from 0.1 to 2.7 Mb. The aberrations are associated with the phenotype in five patients (4.6%), based on the following criteria: de novo aberration; involvement of a known or candidate X-linked nonsyndromic(syndromic) MR (MRX(S)) gene; segregation with the disease in the family; absence in control individuals; and skewed X-inactivation in carrier females. These include deletions that contain the MRX(S) genes CDKL5, OPHN1, and CASK, and duplications harboring CDKL5, NXF5, MECP2, and GDI1. In addition, seven imbalances were apparent novel polymorphic regions because they do not fulfill the proposed criteria. Taken together, our data strongly suggest that not only deletions but also duplications on the X chromosome contribute to the phenotype more often than expected, supporting the increased gene dosage mechanism for deregulation of normal cognitive development.
Collapse
Affiliation(s)
- Guy Froyen
- Human Genome Laboratory, Department for Molecular and Developmental Genetics, VIB, Leuven, Belgium.
| | | | | | | | | | | | | | | | | |
Collapse
|
19
|
Abstract
Developments in genomic microarray technology have revolutionized the study of human genomic copy number variation. This has significantly affected many areas in human genetics, including the field of X-linked mental retardation (XLMR). Chromosome X-specific bacterial artificial chromosomes microarrays have been developed to specifically test this chromosome with a resolution of approximately 100 kilobases. Application of these microarrays in X-linked mental retardation studies has resulted in the identification of novel X-linked mental retardation genes, copy number variation at known X-linked mental retardation genes, and copy number variations harboring as yet unidentified X-linked mental retardation genes. Further enhancements in genomic microarray analysis will soon allow the reliable analysis of all copy number variations throughout this chromosome at the kilobase or single exon resolution. In this review, we describe the developments in this field and specifically highlight the impact of these microarray studies in the field of X-linked mental retardation.
Collapse
Affiliation(s)
- Dorien Lugtenberg
- Department of Human Genetics, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | | | | |
Collapse
|
20
|
Hayashi S, Honda S, Minaguchi M, Makita Y, Okamoto N, Kosaki R, Okuyama T, Imoto I, Mizutani S, Inazawa J. Construction of a high-density and high-resolution human chromosome X array for comparative genomic hybridization analysis. J Hum Genet 2007; 52:397-405. [PMID: 17406783 DOI: 10.1007/s10038-007-0127-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2007] [Accepted: 02/01/2007] [Indexed: 10/23/2022]
Abstract
The human chromosome X is closely associated with congenital disorders and mental retardation (MR), because it contains a significantly higher number of genes than estimated from the proportion in the human genome. We constructed a high-density and high-resolution human chromosome X array (X-tiling array) for comparative genomic hybridization (CGH). The array contains a total of 1,001 bacterial artificial chromosome (BACs) throughout chromosome X except pseudoautosomal regions and two BACs specific for Y. In four hybridizations using DNA samples from healthy males, the ratio of each spotted DNA was scattered between -3SD and 3SD, corresponding to a log(2) ratio of -0.35 and 0.35, respectively. Using DNA samples from patients with known congenital disorders, our X-tiling array was proven to discriminate one-copy losses and gains together with their physical sizes, and also to estimate the percentage of a mosaicism in a patient with mos 45,X[13]/46,X,r(X)[7]. Furthermore, array-CGH in a patient with atypical Schinzel-Giedion syndrome disclosed a 1.1-Mb duplication at Xq22.3 including a part of the IL1RAPL2 gene as a likely causative aberration. The results indicate our in-house X-tiling array to be useful for the identification of cryptic copy-number aberrations containing novel genes responsible for diseases such as congenital disorders and X-linked MR.
Collapse
Affiliation(s)
- Shin Hayashi
- Department of Molecular Cytogenetics, Medical Research Institute and School of Biomedical Science, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8510, Japan
- Department of Pediatric and Developmental Biology, Tokyo Medical and Dental University, 1-5-45 Yushima Bunkyo-ku, Tokyo, 113-8510, Japan
- Core Research for Evolutional Science and Technology (CREST) of Japan Science and Technology Corporation (JST), 4-1-8 Hon-machi Kawaguchi, Saitama, 332-0012, Japan
| | - Shozo Honda
- Department of Molecular Cytogenetics, Medical Research Institute and School of Biomedical Science, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8510, Japan
- Department of Pediatric and Developmental Biology, Tokyo Medical and Dental University, 1-5-45 Yushima Bunkyo-ku, Tokyo, 113-8510, Japan
- Core Research for Evolutional Science and Technology (CREST) of Japan Science and Technology Corporation (JST), 4-1-8 Hon-machi Kawaguchi, Saitama, 332-0012, Japan
| | - Maki Minaguchi
- Department of Molecular Cytogenetics, Medical Research Institute and School of Biomedical Science, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8510, Japan
- Core Research for Evolutional Science and Technology (CREST) of Japan Science and Technology Corporation (JST), 4-1-8 Hon-machi Kawaguchi, Saitama, 332-0012, Japan
| | - Yoshio Makita
- Department of Pediatrics, Asahikawa Medical Collage, Midorigaoka-Higashi 2-1-1-1, Asahikawa, 078-8510, Japan
| | - Nobuhiko Okamoto
- Department of Planning and Research, Osaka Medical Center and Research Institute for Maternal and Child Health, Murodocho 840, Izumi, Osaka, Japan
| | - Rika Kosaki
- Department of Clinical Genetics and Molecular Medicine, National Center for Child Health and Development, 2-10-1 Okura, Setagaya-ku, Tokyo, 157-8535, Japan
| | - Torayuki Okuyama
- Department of Clinical Genetics and Molecular Medicine, National Center for Child Health and Development, 2-10-1 Okura, Setagaya-ku, Tokyo, 157-8535, Japan
| | - Issei Imoto
- Department of Molecular Cytogenetics, Medical Research Institute and School of Biomedical Science, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8510, Japan
- Hard Tissue Genome Research Center, Tokyo Medical and Dental University, 1-5-45 Yushima Bunkyo-ku, Tokyo, 113-8510, Japan
- Core Research for Evolutional Science and Technology (CREST) of Japan Science and Technology Corporation (JST), 4-1-8 Hon-machi Kawaguchi, Saitama, 332-0012, Japan
| | - Shuki Mizutani
- Department of Pediatric and Developmental Biology, Tokyo Medical and Dental University, 1-5-45 Yushima Bunkyo-ku, Tokyo, 113-8510, Japan
| | - Johji Inazawa
- Department of Molecular Cytogenetics, Medical Research Institute and School of Biomedical Science, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8510, Japan.
- Hard Tissue Genome Research Center, Tokyo Medical and Dental University, 1-5-45 Yushima Bunkyo-ku, Tokyo, 113-8510, Japan.
- 21st Century Center of Excellence Program for Molecular Destruction and Reconstitution of Tooth and Bone, Tokyo Medical and Dental University, 1-5-45 Yushima Bunkyo-ku, Tokyo, 113-8510, Japan.
- Core Research for Evolutional Science and Technology (CREST) of Japan Science and Technology Corporation (JST), 4-1-8 Hon-machi Kawaguchi, Saitama, 332-0012, Japan.
| |
Collapse
|
21
|
Froyen G, Bauters M, Boyle J, Van Esch H, Govaerts K, van Bokhoven H, Ropers HH, Moraine C, Chelly J, Fryns JP, Marynen P, Gecz J, Turner G. Loss of SLC38A5 and FTSJ1 at Xp11.23 in three brothers with non-syndromic mental retardation due to a microdeletion in an unstable genomic region. Hum Genet 2007; 121:539-47. [PMID: 17333282 DOI: 10.1007/s00439-007-0343-1] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2006] [Accepted: 02/07/2007] [Indexed: 12/26/2022]
Abstract
Using high resolution X chromosome array-CGH we identified an interstitial microdeletion at Xp11.23 in three brothers with moderate to severe mental retardation (MR) without dysmorphic features. The extent of the deletion was subsequently delineated to about 50 kb by regular PCR and included only the SLC38A5 and FTSJ1 genes. The loss of the FTSJ1 MR gene in males is expected to result in the observed phenotype but the contribution of the deletion of the solute carrier SLC38A5 gene is less clear. Their mother also carries the deletion and completely inactivates the aberrant X chromosome. Interestingly, the distal breakpoint is situated within a 200 kb SSX repeat region that appears to stimulate recombination since subtle copy number changes often occur at this location and it is frequently involved in translocations in tumours. Since this apparent SSX unstable structure is flanked proximally by FTSJ1 and PQBP1, subtle deletions or duplications at this location would be expected to cause MR, as in our family. So far, we have screened a cohort of 300 patients but did not find additional aberrations at the FTSJ1 locus indicating that the frequency is likely to be low.
Collapse
Affiliation(s)
- Guy Froyen
- Human Genome Laboratory, Department for Molecular and Developmental Genetics, VIB, Leuven, Belgium.
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
22
|
Abstract
The sequencing of the human genome and development of high-throughput microarray technologies have enhanced the detection of copy number alterations in cancer research and the study of constitutional chromosomal abnormalities. Microarray-based comparative genomic hybridization (array CGH) has integrated molecular and traditional cytogenetics and has begun to impact the clinician's approach to medical genetics. Clinical applications of array CGH may define new genetic syndromes, expand the phenotype of existing syndromes and characterize a genomic signature of some cancers. As array CGH becomes the initial diagnostic approach for the investigation of constitutional and acquired chromosomal abnormalities, the combination of bioinformatics, robotics and microarray technology will set the stage for a new generation of high-resolution and high-throughput tools for genetic analysis, diagnosis and gene discovery.
Collapse
Affiliation(s)
- Bassem A Bejjani
- Signature Genomic Laboratories, 44 West 6th Avenue, Suite 202, Spokane, WA 99204, USA.
| | | | | | | |
Collapse
|
23
|
Abstract
Microarray-based comparative genomic hybridization (array CGH) is a revolutionary platform that was recently adopted in the clinical laboratory. This technology was first developed as a research tool for the investigation of genomic alterations in cancer. It allows for a high-resolution evaluation of DNA copy number alterations associated with chromosome abnormalities. Array CGH is based on the use of differentially labeled test and reference genomic DNA samples that are simultaneously hybridized to DNA targets arrayed on a glass slide or other solid platform. In this review, we examine the technology and its transformation from a research tool into a maturing diagnostic instrument. We also evaluate the various approaches that have shaped the current platforms that are used for clinical applications. Finally, we discuss the advantages and shortcomings of "whole-genome" arrays and compare their diagnostic use to "targeted" arrays. Depending on their design, microarrays provide distinct advantages over conventional cytogenetic analysis because they have the potential to detect the majority of microscopic and submicroscopic chromosomal abnormalities. This new platform is poised to revolutionize modern cytogenetic diagnostics and to provide clinicians with a powerful tool to use in their increasingly sophisticated diagnostic capabilities.
Collapse
Affiliation(s)
- Bassem A Bejjani
- Signature Genomic Laboratories, LLC, 44 W. 6th Ave., Suite 202, Spokane, WA 99204, USA.
| | | |
Collapse
|
24
|
Zanazzi C, Hersmus R, Veltman IM, Gillis AJM, van Drunen E, Beverloo HB, Hegmans JPJJ, Verweij M, Lambrecht BN, Oosterhuis JW, Looijenga LHJ. Gene expression profiling and gene copy-number changes in malignant mesothelioma cell lines. Genes Chromosomes Cancer 2007; 46:895-908. [PMID: 17620293 DOI: 10.1002/gcc.20475] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Malignant mesothelioma (MM) is an asbestos-induced tumor that acquires aneuploid DNA content during the tumorigenic process. We used instable MM cell lines as an in vitro model to study the impact of DNA copy-number changes on gene expression profiling, in the course of their chromosomal redistribution process. Two MM cell lines, PMR-MM2 (early passages of in vitro culture) and PMR-MM7 (both early and late passages of in vitro culture), were cytogenetically characterized. Genomic gains and losses were precisely defined using microarray-based comparative genomic hybridization (array-CGH), and minimal overlapping analysis led to the identification of the common unbalanced genomic regions. Using the U133Plus 2.0 Affymetrix gene chip array, we analyzed PMR-MM7 early and late passages for genome-wide gene expression, and correlated the differentially expressed genes with copy-number changes. The presence of a high number of genetic imbalances occurring from early to late culture steps reflected the tendency of MM cells toward genomic instability. The selection of specific chromosomal abnormalities observed during subsequent cultures demonstrated the spontaneous evolution of the cancer cells in an in vitro environment. MM cell lines were characterized by copy-number changes associated with the TP53 apoptotic pathway already present at the first steps of in vitro culture. Prolonged culture led to acquisition of additional chromosomal copy-number changes associated with dysregulation of genes involved in cell adhesion, regulation of mitotic cell cycle, signal transduction, carbohydrate metabolism, motor activity, glycosaminoglycan biosynthesis, protein binding activity, lipid transport, ATP synthesis, and methyltransferase activity.
Collapse
Affiliation(s)
- Claudia Zanazzi
- Department of Pathology, Erasmus Medical Center, Daniel den Hoed Cancer Center, Josephine Nefkens Institute, Rotterdam, The Netherlands
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
25
|
Abstract
Learning disability (LD) is a very common, lifelong and disabling condition, affecting about 3% of the population. Despite this, it is only over the past 10-15 years that major progress has been made towards understanding the origins of LD. In particular, genetics driven advances in technology have led to the unequivocal demonstration of the importance of genome imbalance in the aetiology of idiopathic LD (ILD). In this review we provide an overview of these advances, discussing technologies such as multi-telomere FISH and array CGH that have already emerged as well as new approaches that show diagnostic potential for the future. The advances to date have highlighted new considerations such as copy number polymorphisms (CNPs) that can complicate the interpretation of genome imbalance and its relevance to ILD. More importantly though, they have provided a remarkable approximately 15-20% improvement in diagnostic capability as well as facilitating genotype/phenotype correlations and providing new avenues for the identification and understanding of genes involved in neurocognitive function.
Collapse
Affiliation(s)
- S J L Knight
- Oxford Genetics Knowledge Park, Wellcome Trust Centre for Human Genetics, University of Oxford, UK.
| | | |
Collapse
|
26
|
Abstract
Genetic abnormalities frequently give rise to a mental retardation phenotype. Recent advances in resolution of comparative genomic hybridization and genomic sequence annotation has identified new syndromes at chromosome 3q29 and 9q34. The finding of a significant number of copy number polymorphisms in the genome in the normal population, means that assigning pathogenicity to deletions and duplications in patients with mental retardation can be difficult but has been identified for duplications of MECP2 and L1CAM. Novel autosomal genes that cause mental retardation have been identified recently including CC2D1A identified by homozygosity mapping. Several new genes and pathways have been identified in the field of X-linked mental retardation but many more still await identification. Analysis of families where only a single male is affected reveals that the chance of this being due to a single X-linked gene abnormality is significantly less than would be expected if the excess of males in the population is entirely due to X-linked disease. Recent identification of novel X-linked mental retardation genes has identified components of the post-synaptic density and multiple zinc finger transcription factors as disease causing suggesting new mechanisms of disease causation. The first therapeutic treatments of animal models of mental retardation have been reported, a Drosophila model of Fragile X syndrome has been treated with lithium or metabotropic glutamate receptor (mGluR) antagonists and a mouse model of NF1 has been treated with the HMG-CoA reductase inhibitor lavastatin, which improves the learning and memory skills in these models.
Collapse
Affiliation(s)
- F Lucy Raymond
- Department of Medical Genetics, Cambridge Institute of Medical Research, University of Cambridge, Addenbrookes Hospital, Cambridge CB2 2XY, UK.
| | | |
Collapse
|
27
|
Abstract
The search for the genetic defects in constitutional diseases has so far been restricted to direct methods for the identification of genetic mutations in the patients' genome. Traditional methods such as karyotyping, FISH, mutation screening, positional cloning and CGH, have been complemented with newer methods including array-CGH and PCR-based approaches (MLPA, qPCR). These methods have revealed a high number of genetic or genomic aberrations that result in an altered expression or reduced functional activity of key proteins. For a significant percentage of patients with congenital disease however, the underlying cause has not been resolved strongly suggesting that yet other mechanisms could play important roles in their etiology. Alterations of the 'native' epigenetic imprint might constitute such a novel mechanism. Epigenetics, heritable changes that do not rely on the nucleotide sequence, has already been shown to play a determining role in embryonic development, X-inactivation, and cell differentiation in mammals. Recent progress in the development of techniques to study these processes on full genome scale has stimulated researchers to investigate the role of epigenetic modifications in cancer as well as in constitutional diseases. We will focus on mental impairment because of the growing evidence for the contribution of epigenetics in memory formation and cognition. Disturbance of the epigenetic profile due to direct alterations at genomic regions, or failure of the epigenetic machinery due to genetic mutations in one of its components, has been demonstrated in cognitive derangements in a number of neurological disorders now. It is therefore tempting to speculate that the cognitive deficit in a significant percentage of patients with unexplained mental retardation results from epigenetic modifications.
Collapse
Affiliation(s)
- Guy Froyen
- Human Genome Laboratory, VIB, Department Molecular and Developmental Genetics, University of Leuven, Leuven, Belgium.
| | | | | | | |
Collapse
|
28
|
Tyson C, Harvard C, Locker R, Friedman JM, Langlois S, Lewis MES, Van Allen M, Somerville M, Arbour L, Clarke L, McGilivray B, Yong SL, Siegel-Bartel J, Rajcan-Separovic E. Submicroscopic deletions and duplications in individuals with intellectual disability detected by array-CGH. Am J Med Genet A 2006; 139:173-85. [PMID: 16283669 DOI: 10.1002/ajmg.a.31015] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Intellectual disability (ID) affects about 3% of the population (IQ < 70), and in about 40% of moderate (IQ 35-49) to severe ID (IQ < 34), and 70% of cases of mild ID (IQ 50-70), the etiology of the disease remains unknown. It has long been suspected that chromosomal gains and losses undetectable by routine cytogenetic analysis (i.e., less than 5-10 Mb in size) are implicated in ID of unknown etiology. Array CGH has recently been used to perform a genome-wide screen for submicroscopic gains and losses in individuals with a normal karyotype but with features suggestive of a chromosome abnormality. In two recent studies, the technique has demonstrated a approximately 15% detection rate for de novo copy number changes of individual clones or groups of clones. Here, we describe a study of 22 individuals with mild to moderate ID and nonsyndromic pattern of dysmorphic features suspicious of an underlying chromosome abnormality, using the 3 Mb and 1 Mb commercial arrays (Spectral Genomics). Deletions and duplications of 16 clones, previously described to show copy number variability in normal individuals [Iafrate et al., 2004; Lapierre et al., 2004; Schoumans et al., 2004; Vermeesch et al., 2005] were seen in 21/22 subjects and were considered polymorphisms. In addition, three subjects showed submicroscopic deletions and duplications not previously reported as normal variants. Two of these submicroscopic changes were of de novo origin (microdeletions at 7q36.3 and a microduplication at 11q12.3-13.1) and one was of unknown origin as parental testing of origin could not be performed (microduplication of Xp22.3). The clinical description of the three subjects with submicroscopic chromosomal changes at 7q36.3, 11q12.3-13.1, Xp22.3 is provided.
Collapse
Affiliation(s)
- C Tyson
- Department of Pathology, University of British Columbia, Vancouver, Canada
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
29
|
Jehee FS, Rosenberg C, Krepischi-Santos AC, Kok F, Knijnenburg J, Froyen G, Vianna-Morgante AM, Opitz JM, Passos-Bueno MR. An Xq22.3 duplication detected by comparative genomic hybridization microarray (Array-CGH) defines a new locus (FGS5) for FG syndrome. Am J Med Genet A 2006; 139:221-6. [PMID: 16283679 DOI: 10.1002/ajmg.a.30991] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
FG syndrome is an X-linked multiple congenital anomalies (MCA) syndrome. It has been mapped to four distinct loci FGS1-4, through linkage analysis (Xq13, Xp22.3, and Xp11.4-p11.3) and based on the breakpoints of an X chromosome inversion (Xq11:Xq28), but so far no gene has been identified. We describe a boy with FG syndrome who has an inherited duplication at band Xq22.3 detected by comparative genomic hybridization microarray (Array-CGH). These duplication maps outside all four loci described so far for FG syndrome, representing therefore a new locus, which we propose to be called FGS5. MID2, a gene closely related to MID1, which is known to be mutated in Opitz G/BBB syndrome, maps within the duplicated segment of our patient. Since FG and Opitz G/BBB syndromes share many manifestations we considered MID2 a candidate gene for FG syndrome. We also discuss the involvement of other potential genes within the duplicated segment and its relationship with clinical symptoms of our patient, as well as the laboratory abnormalities found in his mother, a carrier of the duplication.
Collapse
Affiliation(s)
- Fernanda Sarquis Jehee
- Centro de Estudos do Genoma Humano, Departamento de Genética e Biologia Evolutiva, Instituto de Biociências, Universidade de São Paulo, São Paulo, Brazil
| | | | | | | | | | | | | | | | | |
Collapse
|
30
|
Abstract
Small, submicroscopic, genomic deletions and duplications (1 kb to 10 Mb) constitute up to 15% of all mutations underlying human monogenic diseases. Novel genomic technologies such as microarray-based comparative genomic hybridization (array CGH) allow the mapping of genomic copy number alterations at this submicroscopic level, thereby directly linking disease phenotypes to gene dosage alterations. At present, the entire human genome can be scanned for deletions and duplications at over 30,000 loci simultaneously by array CGH ( approximately 100 kb resolution), thus entailing an attractive gene discovery approach for monogenic conditions, in particular those that are associated with reproductive lethality. Here, we review the present and future potential of microarray-based mapping of genes underlying monogenic diseases and discuss our own experience with the identification of the gene for CHARGE syndrome. We expect that, ultimately, genomic copy number scanning of all 250,000 exons in the human genome will enable immediate disease gene discovery in cases exhibiting single exon duplications and/or deletions.
Collapse
Affiliation(s)
- Lisenka E L M Vissers
- Department of Human Genetics, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, PO Box 9101 6500 HB Nijmegen, The Netherlands
| | | | | | | |
Collapse
|
31
|
Kiemeney LA, Kuiper RP, Pfundt R, van Reijmersdal S, Schoenberg MP, Aben KK, Niermeijer MF, Witjes JA, Schoenmakers EFPM. No evidence for large-scale germline genomic aberrations in hereditary bladder cancer patients with high-resolution array-based comparative genomic hybridization. Cancer Epidemiol Biomarkers Prev 2006; 15:180-3. [PMID: 16434610 DOI: 10.1158/1055-9965.epi-05-0714] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Affiliation(s)
- Lambertus A Kiemeney
- Department of Urology, Radboud University Nijmegen Medical Centre, P.O. Box 9101, NL-6500 HB Nijmegen, The Netherlands.
| | | | | | | | | | | | | | | | | |
Collapse
|
32
|
Lugtenberg D, Yntema HG, Banning MJG, Oudakker AR, Firth HV, Willatt L, Raynaud M, Kleefstra T, Fryns JP, Ropers HH, Chelly J, Moraine C, Gecz J, van Reeuwijk J, Nabuurs SB, de Vries BBA, Hamel BCJ, de Brouwer APM, van Bokhoven H. ZNF674: a new kruppel-associated box-containing zinc-finger gene involved in nonsyndromic X-linked mental retardation. Am J Hum Genet 2006; 78:265-78. [PMID: 16385466 PMCID: PMC1380234 DOI: 10.1086/500306] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2005] [Accepted: 11/17/2005] [Indexed: 01/13/2023] Open
Abstract
Array-based comparative genomic hybridization has proven to be successful in the identification of genetic defects in disorders involving mental retardation. Here, we studied a patient with learning disabilities, retinal dystrophy, and short stature. The family history was suggestive of an X-linked contiguous gene syndrome. Hybridization of full-coverage X-chromosomal bacterial artificial chromosome arrays revealed a deletion of ~1 Mb in Xp11.3, which harbors RP2, SLC9A7, CHST7, and two hypothetical zinc-finger genes, ZNF673 and ZNF674. These genes were analyzed in 28 families with nonsyndromic X-linked mental retardation (XLMR) that show linkage to Xp11.3; the analysis revealed a nonsense mutation, p.E118X, in the coding sequence of ZNF674 in one family. This mutation is predicted to result in a truncated protein containing the Kruppel-associated box domains but lacking the zinc-finger domains, which are crucial for DNA binding. We characterized the complete ZNF674 gene structure and subsequently tested an additional 306 patients with XLMR for mutations by direct sequencing. Two amino acid substitutions, p.T343M and p.P412L, were identified that were not found in unaffected individuals. The proline at position 412 is conserved between species and is predicted by molecular modeling to reduce the DNA-binding properties of ZNF674. The p.T343M transition is probably a polymorphism, because the homologous ZNF674 gene in chimpanzee has a methionine at that position. ZNF674 belongs to a cluster of seven highly related zinc-finger genes in Xp11, two of which (ZNF41 and ZNF81) were implicated previously in XLMR. Identification of ZNF674 as the third XLMR gene in this cluster may indicate a common role for these zinc-finger genes that is crucial to human cognitive functioning.
Collapse
Affiliation(s)
- Dorien Lugtenberg
- Department of Human Genetics, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
33
|
Looijenga LHJ, Hersmus R, Gillis AJM, Pfundt R, Stoop HJ, van Gurp RJHLM, Veltman J, Beverloo HB, van Drunen E, van Kessel AG, Pera RR, Schneider DT, Summersgill B, Shipley J, McIntyre A, van der Spek P, Schoenmakers E, Oosterhuis JW. Genomic and Expression Profiling of Human Spermatocytic Seminomas: Primary Spermatocyte as Tumorigenic Precursor and DMRT1 as Candidate Chromosome 9 Gene. Cancer Res 2006; 66:290-302. [PMID: 16397242 DOI: 10.1158/0008-5472.can-05-2936] [Citation(s) in RCA: 171] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Spermatocytic seminomas are solid tumors found solely in the testis of predominantly elderly individuals. We investigated these tumors using a genome-wide analysis for structural and numerical chromosomal changes through conventional karyotyping, spectral karyotyping, and array comparative genomic hybridization using a 32 K genomic tiling-path resolution BAC platform (confirmed by in situ hybridization). Our panel of five spermatocytic seminomas showed a specific pattern of chromosomal imbalances, mainly numerical in nature (range, 3-24 per tumor). Gain of chromosome 9 was the only consistent anomaly, which in one case also involved amplification of the 9p21.3-pter region. Parallel chromosome level expression profiling as well as microarray expression analyses (Affymetrix U133 plus 2.0) was also done. Unsupervised cluster analysis showed that a profile containing transcriptional data on 373 genes (difference of > or = 3.0-fold) is suitable for distinguishing these tumors from seminomas/dysgerminomas. The diagnostic markers SSX2-4 and POU5F1 (OCT3/OCT4), previously identified by us, were among the top discriminatory genes, thereby validating the experimental set-up. In addition, novel discriminatory markers suitable for diagnostic purposes were identified, including Deleted in Azospermia (DAZ). Although the seminomas/dysgerminomas were characterized by expression of stem cell-specific genes (e.g., POU5F1, PROM1/CD133, and ZFP42), spermatocytic seminomas expressed multiple cancer testis antigens, including TSP50 and CTCFL (BORIS), as well as genes known to be expressed specifically during prophase meiosis I (TCFL5, CLGN, and LDHc). This is consistent with different cells of origin, the primordial germ cell and primary spermatocyte, respectively. Based on the region of amplification defined on 9p and the associated expression plus confirmatory immunohistochemistry, DMRT1 (a male-specific transcriptional regulator) was identified as a likely candidate gene for involvement in the development of spermatocytic seminomas.
Collapse
Affiliation(s)
- Leendert H J Looijenga
- Department of Pathology, Josephine Nefkens Institute, Erasmus Medical Center/University Medical Center, Rotterdam, The Netherlands.
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
34
|
Verloes A, Bremond-Gignac D, Isidor B, David A, Baumann C, Leroy MA, Stevens R, Gillerot Y, Héron D, Héron B, Benzacken B, Lacombe D, Brunner H, Bitoun P. Blepharophimosis-mental retardation (BMR) syndromes: A proposed clinical classification of the so-called Ohdo syndrome, and delineation of two new BMR syndromes, one X-linked and one autosomal recessive. Am J Med Genet A 2006; 140:1285-96. [PMID: 16700052 DOI: 10.1002/ajmg.a.31270] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
We report on 11 patients from 8 families with a blepharophimosis and mental retardation syndrome (BMRS) phenotype. Using current nosology, five sporadic patients have Ohdo syndrome, associated with congenital hypothyroidism in two of them (thus also compatible with a diagnosis of Young-Simpson syndrome). In two affected sibs with milder phenotype, compensated hypothyroidism was demonstrated. In another family, an affected boy was born to the unaffected sister of a previously reported patient. Finally, in the last sibship, two affected boys in addition had severe microcephaly and neurological anomalies. A definitive clinical and etiologic classification of BMRS is lacking, but closer phenotypic analysis should lead to a more useful appraisal of the BMRS phenotype. We suggest discontinuing the systematic use of the term "Ohdo syndrome" when referring to patients with BMRS. We propose a classification of BMRS into five groups: (1) del(3p) syndrome, (possibly overlooked in older reports); (2) BMRS, Ohdo type, limited to the original patients of Ohdo; (3) BMRS SBBYS (Say-Barber/Biesecker/Young-Simpson) type, with distinctive dysmorphic features and inconstant anomalies including heart defect, optic atrophy, deafness, hypoplastic teeth, cleft palate, joint limitations, and hypothyroidism. BMRS type SBBYS is probably an etiologically heterogeneous phenotype, as AD and apparently AR forms exist; (4) BMRS, MKB (Maat-Kievit-Brunner) type, with coarse, triangular face, which is probably sex-linked; (5) BMRS V (Verloes) type, a probable new type with severe microcephaly, hypsarrhythmia, adducted thumbs, cleft palate, and abnormal genitalia, which is likely autosomal recessive. Types MKB and V are newly described here.
Collapse
Affiliation(s)
- Alain Verloes
- Clinical Genetics Unit, APHP Robert Debré University Hospital, Paris, France.
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
35
|
Sanlaville D, Lapierre JM, Turleau C, Coquin A, Borck G, Colleaux L, Vekemans M, Romana SP. Molecular karyotyping in human constitutional cytogenetics. Eur J Med Genet 2005; 48:214-31. [PMID: 16179218 DOI: 10.1016/j.ejmg.2005.04.013] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2005] [Accepted: 04/08/2005] [Indexed: 01/22/2023]
Abstract
Using array CGH it is possible to detect very small genetic imbalances anywhere in the genome. Its usefulness has been well documented in cancer and more recently in constitutional disorders. In particular it has been used to detect interstitial and subtelomeric submicroscopic imbalances, to characterize their size at the molecular level and to define the breakpoints of chromosomal translocation. Here, we review the various applications of array CGH in constitutional cytogenetics. This technology remains expensive and the existence of numerous sequence polymorphisms makes its interpretation difficult. The challenge today is to transfer this technology in the clinical setting.
Collapse
Affiliation(s)
- Damien Sanlaville
- Service de cytogénétique, laboratoire de cytogénétique, hôpital Necker-Enfants Malades, 149, rue de Sèvres, 75015 Paris, France.
| | | | | | | | | | | | | | | |
Collapse
|
36
|
de Vries BBA, Pfundt R, Leisink M, Koolen DA, Vissers LELM, Janssen IM, Reijmersdal SV, Nillesen WM, Huys EHLPG, Leeuw ND, Smeets D, Sistermans EA, Feuth T, van Ravenswaaij-Arts CMA, van Kessel AG, Schoenmakers EFPM, Brunner HG, Veltman JA. Diagnostic genome profiling in mental retardation. Am J Hum Genet 2005; 77:606-16. [PMID: 16175506 PMCID: PMC1275609 DOI: 10.1086/491719] [Citation(s) in RCA: 442] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2005] [Accepted: 07/26/2005] [Indexed: 01/09/2023] Open
Abstract
Mental retardation (MR) occurs in 2%-3% of the general population. Conventional karyotyping has a resolution of 5-10 million bases and detects chromosomal alterations in approximately 5% of individuals with unexplained MR. The frequency of smaller submicroscopic chromosomal alterations in these patients is unknown. Novel molecular karyotyping methods, such as array-based comparative genomic hybridization (array CGH), can detect submicroscopic chromosome alterations at a resolution of 100 kb. In this study, 100 patients with unexplained MR were analyzed using array CGH for DNA copy-number changes by use of a novel tiling-resolution genomewide microarray containing 32,447 bacterial artificial clones. Alterations were validated by fluorescence in situ hybridization and/or multiplex ligation-dependent probe amplification, and parents were tested to determine de novo occurrence. Reproducible DNA copy-number changes were present in 97% of patients. The majority of these alterations were inherited from phenotypically normal parents, which reflects normal large-scale copy-number variation. In 10% of the patients, de novo alterations considered to be clinically relevant were found: seven deletions and three duplications. These alterations varied in size from 540 kb to 12 Mb and were scattered throughout the genome. Our results indicate that the diagnostic yield of this approach in the general population of patients with MR is at least twice as high as that of standard GTG-banded karyotyping.
Collapse
Affiliation(s)
- Bert B A de Vries
- Department of Human Genetics, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands.
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
37
|
Lugtenberg D, de Brouwer APM, Kleefstra T, Oudakker AR, Frints SGM, Schrander-Stumpel CTRM, Fryns JP, Jensen LR, Chelly J, Moraine C, Turner G, Veltman JA, Hamel BCJ, de Vries BBA, van Bokhoven H, Yntema HG. Chromosomal copy number changes in patients with non-syndromic X linked mental retardation detected by array CGH. J Med Genet 2005; 43:362-70. [PMID: 16169931 PMCID: PMC2563232 DOI: 10.1136/jmg.2005.036178] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Several studies have shown that array based comparative genomic hybridisation (CGH) is a powerful tool for the detection of copy number changes in the genome of individuals with a congenital disorder. In this study, 40 patients with non-specific X linked mental retardation were analysed with full coverage, X chromosomal, bacterial artificial chromosome arrays. Copy number changes were validated by multiplex ligation dependent probe amplification as a fast method to detect duplications and deletions in patient and control DNA. This approach has the capacity to detect copy number changes as small as 100 kb. We identified three causative duplications: one family with a 7 Mb duplication in Xp22.2 and two families with a 500 kb duplication in Xq28 encompassing the MECP2 gene. In addition, we detected four regions with copy number changes that were frequently identified in our group of patients and therefore most likely represent genomic polymorphisms. These results confirm the power of array CGH as a diagnostic tool, but also emphasise the necessity to perform proper validation experiments by an independent technique.
Collapse
Affiliation(s)
- D Lugtenberg
- Department of Human Genetics, Radboud University Nijmegen Medical Centre, P.O. Box 9101, 6500 HB Nijmegen, The Netherlands
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
38
|
Van Esch H, Bauters M, Ignatius J, Jansen M, Raynaud M, Hollanders K, Lugtenberg D, Bienvenu T, Jensen LR, Gecz J, Moraine C, Marynen P, Fryns JP, Froyen G. Duplication of the MECP2 region is a frequent cause of severe mental retardation and progressive neurological symptoms in males. Am J Hum Genet 2005; 77:442-53. [PMID: 16080119 PMCID: PMC1226209 DOI: 10.1086/444549] [Citation(s) in RCA: 454] [Impact Index Per Article: 23.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2005] [Accepted: 07/05/2005] [Indexed: 12/16/2022] Open
Abstract
Loss-of-function mutations of the MECP2 gene at Xq28 are associated with Rett syndrome in females and with syndromic and nonsyndromic forms of mental retardation (MR) in males. By array comparative genomic hybridization (array-CGH), we identified a small duplication at Xq28 in a large family with a severe form of MR associated with progressive spasticity. Screening by real-time quantitation of 17 additional patients with MR who have similar phenotypes revealed three more duplications. The duplications in the four patients vary in size from 0.4 to 0.8 Mb and harbor several genes, which, for each duplication, include the MR-related L1CAM and MECP2 genes. The proximal breakpoints are located within a 250-kb region centromeric of L1CAM, whereas the distal breakpoints are located in a 300-kb interval telomeric of MECP2. The precise size and location of each duplication is different in the four patients. The duplications segregate with the disease in the families, and asymptomatic carrier females show complete skewing of X inactivation. Comparison of the clinical features in these patients and in a previously reported patient enables refinement of the genotype-phenotype correlation and strongly suggests that increased dosage of MECP2 results in the MR phenotype. Our findings demonstrate that, in humans, not only impaired or abolished gene function but also increased MeCP2 dosage causes a distinct phenotype. Moreover, duplication of the MECP2 region occurs frequently in male patients with a severe form of MR, which justifies quantitative screening of MECP2 in this group of patients.
Collapse
Affiliation(s)
- Hilde Van Esch
- Centre for Human Genetics, University Hospital Gasthuisberg, Leuven, Belgium.
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
39
|
Wong A, Lese Martin C, Heretis K, Ruffalo T, Wilber K, King W, Ledbetter DH. Detection and calibration of microdeletions and microduplications by array-based comparative genomic hybridization and its applicability to clinical genetic testing. Genet Med 2005; 7:264-71. [PMID: 15834244 DOI: 10.1097/01.gim.0000160076.14102.ec] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/08/2022] Open
Abstract
PURPOSE Genome-wide telomere screening by fluorescence in situ hybridization (FISH) has revealed that approximately 6% of unexplained mental retardation is due to submicroscopic telomere imbalances. However, the use of FISH for telomere screening is labor intensive and time consuming, given that 41 telomeres are interrogated. We have evaluated the use of array-based Comparative Genomic Hybridization (aCGH) as a more efficient tool for identifying telomere rearrangements. METHODS In this study, 102 individuals with unexplained mental retardation, with either normal or abnormal FISH results, were selected for a blinded retrospective study using aCGH. Results between the two methodologies were compared to ascertain the ability of aCGH to be used in a clinical diagnostics setting. RESULTS We detected 100% of all imbalances previously identified by FISH (n = 17) and identified two additional abnormalities, a 10q telomere duplication and an interstitial duplication of 22q11. Interphase FISH analysis verified all abnormal array results. We also demonstrated that aCGH can accurately calibrate the size of telomere imbalances by using an array with "molecular rulers" for the telomeric regions of 1p, 16p, 17p, and 22q. CONCLUSION This study demonstrates that aCGH is an equivalent methodology to telomere FISH for detecting submicroscopic deletions. In addition, small duplications that are not easily visible by FISH can be accurately detected using aCGH. Because aCGH allows simultaneous interrogation of hundreds to thousands of DNA probes and is more amenable to automation, it offers an efficient and high-throughput alternative for detecting and calibrating unbalanced rearrangements, both of the telomere region, as well as other genomic locations.
Collapse
Affiliation(s)
- Andrew Wong
- Department of Human Genetics, Emory University School of Medicine, Atlanta, Georgia 30322, USA
| | | | | | | | | | | | | |
Collapse
|
40
|
Bauters M, Van Esch H, Marynen P, Froyen G. X chromosome array-CGH for the identification of novel X-linked mental retardation genes. Eur J Med Genet 2005; 48:263-75. [PMID: 16179222 DOI: 10.1016/j.ejmg.2005.04.008] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2005] [Revised: 03/30/2005] [Accepted: 04/26/2005] [Indexed: 01/25/2023]
Abstract
Array-CGH technology for the detection of submicroscopic copy number changes in the genome has recently been developed for the identification of novel disease-associated genes. It has been estimated that submicroscopic genomic deletions or duplications will be present in 5-7% of patients with idiopathic mental retardation (MR). Since 30% more males than females are diagnosed with MR, we have developed a full coverage X chromosome array-CGH with a theoretical resolution of 82 kb, for the detection of copy number alterations in patients with suspected X-linked mental retardation (XLMR). First, we have validated the genomic location of X-derived clones through male versus female hybridisations. Next, we validated our array for efficient and reproducible detection of known alterations in XLMR patients. In all cases, we were able to detect the deletions and duplications in males as well as females. Due to the high resolution of our X-array, the boundaries of the genomic aberrations could clearly be identified making genotype-phenotype studies more reliable. Here, we describe the production and validation of a full coverage X-array-CGH, which will allow for fast and easy screening of submicroscopic copy number alterations in XLMR patients with the aim to identify novel MR genes or mechanisms involved in a deranged cognitive development.
Collapse
Affiliation(s)
- Marijke Bauters
- Human Genome Laboratory, Department of Human Genetics, Flanders Interuniversity Institute for Biotechnology (VIB), Leuven, Belgium
| | | | | | | |
Collapse
|
41
|
Cheung SW, Shaw CA, Yu W, Li J, Ou Z, Patel A, Yatsenko SA, Cooper ML, Furman P, Stankiewicz P, Stankiewicz P, Lupski JR, Chinault AC, Beaudet AL. Development and validation of a CGH microarray for clinical cytogenetic diagnosis. Genet Med 2005; 7:422-32. [PMID: 16024975 DOI: 10.1097/01.gim.0000170992.63691.32] [Citation(s) in RCA: 204] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
PURPOSE We developed a microarray for clinical diagnosis of chromosomal disorders using large insert genomic DNA clones as targets for comparative genomic hybridization (CGH). METHODS The array contains 362 FISH-verified clones that span genomic regions implicated in over 40 known human genomic disorders and representative subtelomeric clones for each of the 41 clinically relevant human chromosome telomeres. Three or four clones from almost all deletion or duplication genomic regions and three or more clones for each subtelomeric region were included. We tested chromosome microarray analysis (CMA) in a masked fashion by examining genomic DNA from 25 patients who were previously ascertained in a genetic clinic and studied by conventional cytogenetics. A novel software package implemented in the R statistical programming language was developed for normalization, visualization, and inference. RESULTS The CMA results were entirely consistent with previous cytogenetic and FISH findings. For clone by clone analysis, the sensitivity was estimated to be 96.7% and the specificity was 99.1%. Major advantages of this selected human genome array include the following: interrogation of clinically relevant genomic regions, the ability to test for a wide range of duplication and deletion syndromes in a single analysis, the ability to detect duplications that would likely be undetected by metaphase FISH, and ease of confirmation of suspected genomic changes by conventional FISH testing currently available in the cytogenetics laboratory. CONCLUSION The array is an attractive alternative to telomere FISH and locus-specific FISH, but it does not include uniform coverage across the arms of each chromosome and is not intended to substitute for a standard karyotype. Limitations of CMA include the inability to detect both balanced chromosome changes and low levels of mosaicism.
Collapse
Affiliation(s)
- Sau W Cheung
- Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
42
|
Koolen DA, Reardon W, Rosser EM, Lacombe D, Hurst JA, Law CJ, Bongers EMHF, van Ravenswaaij-Arts CM, Leisink MAR, van Kessel AG, Veltman JA, de Vries BBA. Molecular characterisation of patients with subtelomeric 22q abnormalities using chromosome specific array-based comparative genomic hybridisation. Eur J Hum Genet 2005; 13:1019-24. [PMID: 15986041 DOI: 10.1038/sj.ejhg.5201456] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
The 22q13 deletion syndrome is associated with global developmental delay, absent or delayed speech, and generalised hypotonia. In this study, the size and nature of 22q13 deletions (n=9) were studied in detail by high-resolution chromosome specific array-based comparative genomic hybridisation (array CGH). The deletion sizes varied considerably between the different patients, that is, the largest deletion spanning 8.4 Mb with the breakpoint mapping to 22q13.2 and the smallest deletion spanning 3.3 Mb with the breakpoint mapping to 22q13.31. In one case, a unique subtelomeric 3.9 Mb deletion associated with a 2.0 Mb duplication of 22q13 was observed, adding to a growing number of similar cases identified for other chromosome ends. Remarkably, this patient had signs suggestive of retinitis pigmentosa, which has never been reported before in the 22q13 deletion syndrome. The identification of two pairs of recurrent proximal breakpoints on 22q13 suggests that these specific regions may be prone to recombination, due to yet unknown genome architectural features. In addition to the copy number changes on 22q13, a duplication of approximately 330 kb on 22q11.1 was observed and shown to be a genetic large-scale copy number variation without clinical consequences. The current study failed to reveal relationships between the clinical features and the deletion sizes. Global developmental delay and absent or severely delayed speech were observed in all patients, whereas hypotonia was present in 89% of the cases (8/9). This study underscores the utility of array CGH for characterising the size and nature of subtelomeric deletions, such as monosomy 22q13, and underlines the considerable variability in deletion size in the 22q13 deletion syndrome regardless of the clinical phenotype.
Collapse
Affiliation(s)
- David A Koolen
- 1Department of Human Genetics, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|