Angaben zur Quelle [Bearbeiten]
| Autor | Eleni Katzaki |
| Titel | Clinical Impact of Contemporary Molecular Cytogenetics |
| Ort | Siena |
| Jahr | 2009 |
| URL | http://www3.unisi.it/ricerca/dottorationweb/genetica_medica/Tesi/Katzaki%20PhD%20Thesis.pdf |
Literaturverz. |
no |
| Fußnoten | no |
| Fragmente | 9 |
| [1.] Analyse:Ftp/Fragment 009 25 - Diskussion Zuletzt bearbeitet: 2014-12-18 18:18:24 Graf Isolan | Fragment, Ftp, Katzaki 2009, SMWFragment, Schutzlevel, Verschleierung, ZuSichten |
|
|
|
| Untersuchte Arbeit: Seite: 9, Zeilen: 25-27 |
Quelle: Katzaki 2009 Seite(n): 16, Zeilen: 1 ff. |
|---|---|
| In the 1990s the introduction of molecular cytogenetic techniques into the clinical laboratory setting represented a major advance in the ability to detect known syndromes and identify chromosomal rearrangements of unknown [origin.] | In the 1990s the introduction of molecular cytogenetic techniques into the clinical laboratory setting represented a major advance in the ability to detect known syndromes and identify chromosomal rearrangements of unknown origin. |
No hint is given that this text comes from another source. |
|
| [2.] Analyse:Ftp/Fragment 010 01 - Diskussion Zuletzt bearbeitet: 2014-12-18 16:31:44 SleepyHollow02 | Fragment, Ftp, Katzaki 2009, SMWFragment, Schutzlevel, Verschleierung, ZuSichten |
|
|
|
| Untersuchte Arbeit: Seite: 10, Zeilen: 1 ff. (kpl.) |
Quelle: Katzaki 2009 Seite(n): 16, Zeilen: 3 ff. |
|---|---|
| FISH, which is the annealing of fluorescently labelled locus-specific probes to their complimentary sequences in the genome, allowed the detection of specific microdeletion syndromes. [3] There are currently a number of commercially available FISH probes for the most common disorders and this method is still predominantly used when the clinical phenotype is suggestive of a particular disorder. Several other FISH-based methods, including spectral karyotyping (SKY), multicolour FISH (m-FISH), and comparative genomic hybridization (CGH) have proven extremely useful in the identification of unknown chromosomal material. SKY and m-FISH rely mainly on the principal of differentially labelling each chromosome using a unique combination of fluorochromes and are especially beneficial for identifying the origin and content of supernumerary marker chromosomes (SMCs) and complex chromosome rearrangements (CCRs) that involve more than two chromosomes. CGH was originally introduced for the cytogenetic analysis of solid tumors, which can be difficult to culture and involves the differential labeling of DNA from a test sample and a reference sample. The fluorescently labelled reactions are combined and hybridized to metaphase spreads from chromosomally normal individuals. Gains and losses of the genome in the test sample relative to the control sample are represented as ratios that are quantified from digital image analysis. This method allows the investigation of the whole genome and is very useful for determining the origin of unknown genetic material, such as SMCs and other unbalanced rearrangements. However, CGH does not detect balanced rearrangements, the resolution is on the order of 5–10 Mb and consequently many genomic disorders cannot be detected. [4]
3. Trask, B.J., Fluorescence in situ hybridization: applications in cytogenetics and gene mapping. Trends Genet, 1991. 7(5): p. 149-54. 4. Edelmann, L. and K. Hirschhorn, Clinical utility of array CGH for the detection of chromosomal imbalances associated with mental retardation and multiple congenital anomalies. Ann N Y Acad Sci, 2009. 1151: p. 157-66. |
Fluorescence in situ hybridization (FISH), which is the annealing of fluorescently labelled locusspecific probes to their complimentary sequences in the genome, allowed the detection of specific microdeletion syndromes (Fig. 2).5 There are currently a number of commercially available FISH probes for the most common disorders, and this method is still predominantly used when the clinical phenotype is suggestive of a particular disorder. Several other FISH-based methods, including spectral karyotyping (SKY), multicolour FISH (m-FISH),5 and comparative genomic hybridization (CGH) have proven extremely useful in the identification of unknown chromosomal material. SKY and m-FISH rely mainly on the principal of differentially labelling each chromosome using a unique combination of fluorochromes and are especially beneficial for identifying the origin and content of supernumerary marker chromosomes (SMCs) and complex chromosome rearrangements (CCRs) that involve more than two chromosomes. CGH was originally introduced for the cytogenetic analysis of solid tumors, which can be difficult to culture, and involves the differential labeling of DNA from a test sample and a reference sample (Fig. 3).5 The fluorescently labelled reactions are combined and hybridized to metaphase spreads from chromosomally normal individuals. Gains and losses of the genome in the test sample relative to the control sample are represented as ratios that are quantified from digital image analysis. This method allows the investigation of the whole genome and is very useful for determining the origin of unknown genetic material, such as SMCs and other unbalanced rearrangements.5 However, CGH does not detect balanced rearrangements, and the resolution is on the order of 5–10Mb, and consequently many genomic disorders cannot be detected.3
3 Edelmann L, Hirschhorn K: Clinical utility of array CGH for the detection of chromosomal imbalances associated with mental retardation and multiple congenital anomalies. Ann N Y Acad Sci 2009; 1151: 157-166. 5 Trask BJ: Fluorescence in situ hybridization: applications in cytogenetics and gene mapping. Trends Genet 1991; 7: 149-154. |
Kein Hinweis auf die Quelle. |
|
| [3.] Analyse:Ftp/Fragment 012 01 - Diskussion Zuletzt bearbeitet: 2014-12-18 17:16:41 SleepyHollow02 | Fragment, Ftp, Katzaki 2009, SMWFragment, Schutzlevel, Verschleierung, ZuSichten |
|
|
|
| Untersuchte Arbeit: Seite: 12, Zeilen: 1 ff. (kpl.) |
Quelle: Katzaki 2009 Seite(n): 18, Zeilen: 1 ff. |
|---|---|
| The need to screen the whole genome at a resolution that surpassed the existing technologies led to the implementation of microarray based CGH. The principle is very similar to that employed for traditional CGH, where two differentially labelled specimens are co-hybridized in the presence of Cot1 DNA. However, instead of metaphase spreads, the hybridization targets are DNA substrates immobilized on a glass slide. [5] [6] [7] Subsequently, the arrays are scanned and the resultant data are analyzed by software that computes the log 2 ratios for a variety of copy number differences between a patient and reference sample (Fig. 2).
Fig. 2⏐ Schematic representation of an array-CGH experiment. a) Test and reference DNA are differentially labelled, co-precipitated and hybridised to an array. b) and c) After wash procedures, the slides are analysed through a scanner and fluorescence intensities of each probe are determined. d) After imaging processing and data normalization, the log2 ratios of the probes are plotted as a function of chromosomal position. Probes with a value of zero represent equal fluorescence intensity ratio between sample and reference. Each dot represents a single probe spotted on the array. In this representation, copy number loss shift the ratio to the left and copy number gains shift the ratio to the right. |
Fig. 4⏐ Schematic representation of an array-CGH experiment. a) Test and reference DNA are differentially labelled, co-precipitated and hybridised to an array. b) and c) After wash procedures, the slides are analysed through a scanner and fluorescence intensities of each probe are determined. d) After imaging processing and data normalization, the log2 ratios of the probes are plotted as a function of chromosomal position. Probes with a value of zero represent equal fluorescence intensity ratio between sample and reference. Each dot represents a single probe spotted on the array. In this representation, copy number loss shift the ratio to the left and copy number gains shift the ratio to the right. (d) The need to screen the whole genome at a resolution that surpassed the existing technologies led to the implementation of microarray based CGH. The principle is very similar to that employed for traditional CGH, where two differentially labeled specimens are cohybridized in the presence of Cot1 DNA; however, instead of metaphase spreads, the hybridization targets are DNA substrates immobilized on a glass slide.5-7 Subsequently, the arrays are scanned and the resultant data are analyzed by software that computes the log 2 ratios for a variety of copy number differences between a patient and reference sample (Fig. 4) |
Kein Hinweis auf die Quelle. |
|
| [4.] Analyse:Ftp/Fragment 013 01 - Diskussion Zuletzt bearbeitet: 2014-12-18 17:47:11 SleepyHollow02 | Fragment, Ftp, Katzaki 2009, SMWFragment, Schutzlevel, Verschleierung, ZuSichten |
|
|
|
| Untersuchte Arbeit: Seite: 10, Zeilen: 1 ff. (kpl.) |
Quelle: Katzaki 2009 Seite(n): 18 f., Zeilen: 18: last lines; 19: 1 ff. |
|---|---|
| Consequently, aCGH is an entirely molecular technique with a cytogenetic application and represents a hybrid method that requires the expertise of both specialties. The current limitations of the technology include the inability to detect balanced chromosome rearrangements and the equivocal nature of copy number alterations of unknown significance that may be identified. Nevertheless, it is being used routinely in the clinical setting with a normal chromosome result in cases of intellectual disability and/or multiple congenital anomalies (ID/MCA); as a result the diagnostic yield in this patient group has increased considerably. [4]
1.2 Array – CGH Methodologies Two major types of array targets are currently being utilized. Initially, bacterial artificial chromosomes (BACs) were the array target of choice. [6] However, more recently, oligonucleotide arrays have been adopted due to the increased genome coverage they afford. The design of both array types was made possible by the availability of the complete map and sequence of the human genome. The BAC arrays may contain DNA isolated from large insert clones that range in size from 150–200 Kb, spotted directly onto the array or may employ the spotting of PCR products amplified from the BAC clones. [8] These arrays are generally very sensitive and results can be directly validated with FISH using the BAC DNA as a probe. However, production of BAC DNA is laborintensive and the resolution is limited to 50–100 Kb, even on a whole genome tiling path array. [9] Oligonucleotide arrays offer a flexible format with the potential for very high resolution and customization. Several different platforms are available for oligonucleotide arrays, some of which were adapted from genome wide SNP-based oligonucleotide markers and others that were created from a library of virtual probes that span the genome, and consequently can be constructed to have extremely high resolution. [10] Both BAC and [oligonucleotide arrays have been used successfully to detect copy number changes in patients with ID/MCA and autism.] 4. Edelmann, L. and K. Hirschhorn, Clinical utility of array CGH for the detection of chromosomal imbalances associated with mental retardation and multiple congenital anomalies. Ann N Y Acad Sci, 2009. 1151: p. 157-66. 6. Pinkel, D., et al., High resolution analysis of DNA copy number variation using comparative genomic hybridization to microarrays. Nat Genet, 1998. 20(2): p. 207-11. 8. Ylstra, B., et al., BAC to the future! or oligonucleotides: a perspective for micro array comparative genomic hybridization (array CGH). Nucleic Acids Res, 2006. 34(2): p. 445-50. 9. Ishkanian, A.S., et al., A tiling resolution DNA microarray with complete coverage of the human genome. Nat Genet, 2004. 36(3): p. 299-303. 10. Shaikh, T.H., Oligonucleotide arrays for high-resolution analysis of copy number alteration in mental retardation/multiple congenital anomalies. Genet Med, 2007. 9(9): p. 617-25. |
Consequently, array-CGH is an entirely molecular technique with a cytogenetic application and represents a hybrid method that requires the expertise of both specialties. The current limitations of the technology include the inability to detect
[page 19:] balanced chromosome rearrangements and the equivocal nature of copy number alterations of unknown significance that may be identified. Nevertheless, it is being used routinely in the clinical setting with a normal chromosome result in cases of mental retardation and/or multiple congenital anomalies (MR/MCA); as a result the diagnostic yield in this patient group has increased considerably. 3 1.2 Array – CGH Methodologies Two major types of array targets are currently being utilized. Initially, bacterial artificial chromosomes (BACs) were the array target of choice.6 However, more recently, oligonucleotide arrays have been adopted due to the increased genome coverage they afford. The design of both array types was made possible by the availability of the complete map and sequence of the human genome. The BAC arrays may contain DNA isolated from large insert clones that range in size from 150–200 kb, spotted directly onto the array or may employ the spotting of PCR products amplified from the BAC clones.8 These arrays are generally very sensitive and results can be directly validated with FISH using the BAC DNA as a probe. However, production of BAC DNA is labor-intensive, and the resolution is limited to 50–100 kb, even on a whole genome tiling path array.9 Oligonucleotide arrays offer a flexible format with the potential for very high resolution and customization. Several different platforms are available for oligonucleotide arrays, some of which were adapted from genomewide SNP-based oligonucleotide markers and others that were created from a library of virtual probes that span the genome, and consequently can be constructed to have extremely high resolution.10 Both BAC and oligonucleotide arrays have been used successfully to detect copy number changes in patients with MR/MCA and autism. 3 Edelmann L, Hirschhorn K: Clinical utility of array CGH for the detection of chromosomal imbalances associated with mental retardation and multiple congenital anomalies. Ann N Y Acad Sci 2009; 1151: 157-166. 6 Pinkel D, Segraves R, Sudar D et al: High resolution analysis of DNA copy number variation using comparative genomic hybridization to microarrays. Nat Genet 1998; 20: 207-211. 8 Ylstra B, van den Ijssel P, Carvalho B, Brakenhoff RH, Meijer GA: BAC to the future! or oligonucleotides: a perspective for micro array comparative genomic hybridization (array CGH). Nucleic Acids Res 2006; 34: 445-450. 9 Ishkanian AS, Malloff CA, Watson SK et al: A tiling resolution DNA microarray with complete coverage of the human genome. Nat Genet 2004; 36: 299-303. 10 Shaikh TH: Oligonucleotide arrays for high-resolution analysis of copy number alteration in mental retardation/multiple congenital anomalies. Genet Med 2007; 9: 617-625. |
Kein Hinweis auf die Quelle. |
|
| [5.] Analyse:Ftp/Fragment 014 01 - Diskussion Zuletzt bearbeitet: 2014-12-18 18:18:20 SleepyHollow02 | Fragment, Ftp, Katzaki 2009, SMWFragment, Schutzlevel, Verschleierung, ZuSichten |
|
|
|
| Untersuchte Arbeit: Seite: 14, Zeilen: 1 ff. (kpl.) |
Quelle: Katzaki 2009 Seite(n): 19 f., Zeilen: 19: 22 ff.; 20: 1 ff. |
|---|---|
| [Both BAC and] oligonucleotide arrays have been used successfully to detect copy number changes in patients with ID/MCA and autism. A number of different array design approaches have been taken for diagnostic purposes. A targeted array is one that contains specific regions of the genome, such as the subtelomeres and those responsible for known microdeletion/microduplication syndromes, but does not have probes that span the whole genome. [11] [12] [13] This type of array was initially used for clinical applications in postnatal specimens but has also been implemented for prenatal specimens with an abnormal ultrasound finding or for general screening purposes. [14] [15] [16] A whole genome or tiling path array offers full genome coverage with a resolution that is dependent on the spacing of the probes. For clinical testing the resolution generally involves a spacing of 50 Kb to 1 Mb between adjacent probes on the array often with additional coverage at the subtelomeric regions. [17] [18] The enhanced coverage of whole genome arrays identifies an additional 5% of abnormalities when compared to a targeted array. [19] [20] For research purposes, very high density oligonucleotide whole genome arrays and region specific custom arrays have been instrumental in defining new syndromes, detecting target gene deletions and characterizing breakpoint regions. [21] [22] [23]
11. Bejjani, B.A., et al., Use of targeted array-based CGH for the clinical diagnosis of chromosomal imbalance: is less more? Am J Med Genet A, 2005. 134(3): p. 259-67. 12. Bejjani, B.A. and L.G. Shaffer, Application of array-based comparative genomic hybridization to clinical diagnostics. J Mol Diagn, 2006. 8(5): p. 528-33. 13. Shaffer, L.G., Risk estimates for uniparental disomy following prenatal detection of a nonhomologous Robertsonian translocation. Prenat Diagn, 2006. 26(4): p. 303-7. 14. Le Caignec, C., et al., Detection of genomic imbalances by array based comparative genomic hybridisation in fetuses with multiple malformations. J Med Genet, 2005. 42(2): p. 121-8. 15. Sahoo, T., et al., Microarray based comparative genomic hybridization testing in deletion bearing patients with Angelman syndrome: genotype-phenotype correlations. J Med Genet, 2006. 43(6): p. 512-6. 16. Kitsiou-Tzeli, S., et al., Prenatal diagnosis of a de novo partial trisomy 10p12.1-12.2 pter originating from an unbalanced translocation onto 15qter and confirmed with array CGH. Prenat Diagn, 2008. 28(8): p. 770-2. 17. Veltman, J.A. and B.B. de Vries, Diagnostic genome profiling: unbiased whole genome or targeted analysis? J Mol Diagn, 2006. 8(5): p. 534-7; discussion 537-9. 18. Toruner, G.A., et al., An oligonucleotide based array-CGH system for detection of genome wide copy number changes including subtelomeric regions for genetic evaluation of mental retardation. Am J Med Genet A, 2007. 143A(8): p. 824-9. 19. Baldwin, E.L., et al., Enhanced detection of clinically relevant genomic imbalances using a targeted plus whole genome oligonucleotide microarray. Genet Med, 2008. 10(6): p. 415-29. 20. Veltman, J.A. and B.B. de Vries, Whole-genome array comparative genome hybridization: the preferred diagnostic choice in postnatal clinical cytogenetics. J Mol Diagn, 2007. 9(2): p. 277. 21. Selzer, R.R., et al., Analysis of chromosome breakpoints in neuroblastoma at subkilobase resolution using fine-tiling oligonucleotide array CGH. Genes Chromosomes Cancer, 2005. 44(3): p. 305-19. 22. Urban, A.E., et al., High-resolution mapping of DNA copy alterations in human chromosome 22 using high-density tiling oligonucleotide arrays. Proc Natl Acad Sci U S A, 2006. 103(12): p. 4534-9. 23. Wong, L.J., et al., Utility of oligonucleotide array-based comparative genomic hybridization for detection of target gene deletions. Clin Chem, 2008. 54(7): p. 1141-8. |
Both BAC and oligonucleotide arrays have been used successfully to detect copy number changes in patients with MR/MCA and autism. A number of different array design approaches have been taken for diagnostic purposes. A targeted array is one that contains specific regions of the genome, such as the subtelomeres and those responsible for known microdeletion/microduplication syndromes, but does not have probes that span the whole genome.11-13 This type of
[page 20:] array was initially used for clinical applications in postnatal specimens but has also been implemented for prenatal specimens with an abnormal ultrasound finding or for general screening purposes.14-16 A whole genome or tiling path array offers full genome coverage with a resolution that is dependent on the spacing of the probes. For clinical testing the resolution generally involves a spacing of 50 kb to 1 Mb between adjacent probes on the array often with additional coverage at the subtelomeric regions.17-19 The enhanced coverage of whole genome arrays identifies an additional 5% of abnormalities when compared to a targeted array.19,20 For research purposes, very high density oligonucleotide whole genome arrays and region specific custom arrays have been instrumental in defining new syndromes, detecting target gene deletions and characterizing breakpoint regions.3,21-24 3 Edelmann L, Hirschhorn K: Clinical utility of array CGH for the detection of chromosomal imbalances associated with mental retardation and multiple congenital anomalies. Ann N Y Acad Sci 2009; 1151: 157-166. 11 Bejjani BA, Saleki R, Ballif BC et al: Use of targeted array-based CGH for the clinical diagnosis of chromosomal imbalance: is less more? Am J Med Genet A 2005; 134: 259-267. 12 Bejjani BA, Shaffer LG: Application of array-based comparative genomic hybridization to clinical diagnostics. J Mol Diagn 2006; 8: 528-533. 13 Shaffer LG, Kashork CD, Saleki R et al: Targeted genomic microarray analysis for identification of chromosome abnormalities in 1500 consecutive clinical cases. J Pediatr 2006; 149: 98-102. 14 Le Caignec C, Boceno M, Saugier-Veber P et al: Detection of genomic imbalances by array based comparative genomic hybridisation in fetuses with multiple malformations. J Med Genet 2005; 42: 121-128. 15 Sahoo T, Cheung SW, Ward P et al: Prenatal diagnosis of chromosomal abnormalities using array-based comparative genomic hybridization. Genet Med 2006; 8: 719-727. 16 Kitsiou-Tzeli S, Sismani C, Karkaletsi M et al: Prenatal diagnosis of a de novo partial trisomy 10p12.1-12.2 pter originating from an unbalanced translocation onto 15qter and confirmed with array CGH. Prenat Diagn 2008; 28: 770-772. 17 Veltman JA, de Vries BB: Diagnostic genome profiling: unbiased whole genome or targeted analysis? J Mol Diagn 2006; 8: 534-537; discussion 537-539. 18 Toruner GA, Streck DL, Schwalb MN, Dermody JJ: An oligonucleotide based array-CGH system for detection of genome wide copy number changes including subtelomeric regions for genetic evaluation of mental retardation. Am J Med Genet A 2007; 143A: 824-829. 19 Baldwin EL, Lee JY, Blake DM et al: Enhanced detection of clinically relevant genomic imbalances using a targeted plus whole genome oligonucleotide microarray. Genet Med 2008; 10: 415-429. 20 Veltman JA, de Vries BB: Whole-genome array comparative genome hybridization: the preferred diagnostic choice in postnatal clinical cytogenetics. J Mol Diagn 2007; 9: 277. 21 Selzer RR, Richmond TA, Pofahl NJ et al: Analysis of chromosome breakpoints in neuroblastoma at sub-kilobase resolution using fine-tiling oligonucleotide array CGH. Genes Chromosomes Cancer 2005; 44: 305-319. 22 Urban AE, Korbel JO, Selzer R et al: High-resolution mapping of DNA copy alterations in human chromosome 22 using high-density tiling oligonucleotide arrays. Proc Natl Acad Sci U S A 2006; 103: 4534-4539. 23 Wong LJ, Dimmock D, Geraghty MT et al: Utility of oligonucleotide arraybased comparative genomic hybridization for detection of target gene deletions. Clin Chem 2008; 54: 1141-1148. 24 Balikova I, Lehesjoki AE, de Ravel TJ et al: Deletions in the VPS13B (COH1) gene as a cause of Cohen syndrome. Hum Mutat 2009. |
Kein Hinweis auf die Quelle. |
|
| [6.] Analyse:Ftp/Fragment 016 04 - Diskussion Zuletzt bearbeitet: 2014-12-18 18:43:58 SleepyHollow02 | Fragment, Ftp, Katzaki 2009, SMWFragment, Schutzlevel, Verschleierung, ZuSichten |
|
|
|
| Untersuchte Arbeit: Seite: 16, Zeilen: 4-7, 11 ff. |
Quelle: Katzaki 2009 Seite(n): 21 f, Zeilen: 21: 9 ff.; 22: 1 ff. |
|---|---|
| "Recognizable syndromes" are recognizable because they exhibit, to the trained clinician, a constellation of signs and symptoms that arouse sufficient suspicion to cause the clinician to order a test that will confirm the clinical diagnosis. The advent of molecular tools such as aCGH, allows us to define the rearrangements in a more detailed and comprehensive manner. A report has highlighted the usefulness of aCGH to characterize the Angelman syndrome/Prader-Willi syndrome (AS/PWS) region. [15] This age-old pattern of medical practice creates a loop that includes the patient, the clinician, and the laboratory and, in doing so, reinforces these recognizable features, cements them to the syndrome, and makes the clinician more confident in his/her diagnostic skills. With the application of aCGH to individuals with nonspecific developmental delay (DD) and/or intellectual disability (ID), with or without dysmorphic features (DF), it is now clear that many recognizable microdeletions and microduplication syndromes have a much wider spectrum of clinical presentation than was previously appreciated. [39] [25] A more complete understanding of the full clinical spectrum of these disorders will be achieved as the use of aCGH in the clinic becomes more prevalent and as correlations of these clinical findings with the genomic lesions are made. Existing website resources such as DECIPHER (see 1.5). [40] Many recognizable microdeletion syndromes are caused by nonallelic homologous recombination (NAHR) mediated by flanking low-copy repeat (LCR) sequences. [41] Interchromosomal and interchromatid NAHR between LCRs in direct orientation result in reciprocal duplication and deletion, whereas intrachromatid NAHR only creates deletion.
25. Shaffer, L.G. and T.H. Bui, Molecular cytogenetic and rapid aneuploidy detection methods in prenatal diagnosis. Am J Med Genet C Semin Med Genet, 2007. 145C(1): p. 87-98. 39. Krepischi-Santos, A.C., et al., Whole-genome array-CGH screening in undiagnosed syndromic patients: old syndromes revisited and new alterations. Cytogenet Genome Res, 2006. 115(3-4): p. 254-61. 40. Firth, H.V., et al., DECIPHER: Database of Chromosomal Imbalance and Phenotype in Humans Using Ensembl Resources. Am J Hum Genet, 2009. 84(4): p. 524-33. 41. Gu, W., F. Zhang, and J.R. Lupski, Mechanisms for human genomic rearrangements. Pathogenetics, 2008. 1(1): p. 4. |
"Recognizable syndromes" are recognizable because they exhibit, to the trained clinician, a constellation of signs and symptoms that arouse sufficient suspicion to cause the clinician to order a test that will confirm the clinical diagnosis. This age-old pattern of medical practice creates a loop that includes the patient, the clinician, and the laboratory and, in doing so, reinforces these recognizable features, cements them to the syndrome, and makes the clinician more confident in his/her diagnostic skills.
[...] With the application of array-CGH to individuals with nonspecific developmental delay (DD) and/or mental retardation (MR), with or without dysmorphic features (DF), it is now clear that many recognizable microdeletions and microduplication syndromes have a much wider spectrum of clinical presentation than was previously appreciated.27,28 A more complete understanding of the full clinical spectrum of these disorders will be achieved as the use of array-CGH in the clinic becomes more [page 22:] prevalent and as correlations of these clinical findings with the genomic lesions are made. Existing website resources such as DECIPHER (DatabasE of Chromosomal Imbalance and Phenotype in Humans using Ensembl Resources; http://www.sanger.ac.uk! PostGenomics/decipherl) (Wellcome Trust Sanger Inst. 2007) may facilitate widespread appreciation of such phenotypic variability (see 1.5).32 1.3.2 Identifying the reciprocal products of known conditions. Many recognizable microdeletion syndromes are caused by nonallelic homologous recombination (NAHR) mediated by flanking low-copy repeat (LCR) sequences.33 Interchromosomal and interchromatid NAHR between LCRs in direct orientation result in reciprocal duplication and deletion, whereas intrachromatid NAHR only creates deletion.33 27 Krepischi-Santos AC, Vianna-Morgante AM, Jehee FS et al: Whole-genome array-CGH screening in undiagnosed syndromic patients: old syndromes revisited and new alterations. Cytogenet Genome Res 2006; 115: 254-261. 28 Shaffer LG, Bejjani BA, Torchia B, Kirkpatrick S, Coppinger J, Ballif BC: The identification of microdeletion syndromes and other chromosome abnormalities: cytogenetic methods of the past, new technologies for the future. Am J Med Genet C Semin Med Genet 2007; 145C: 335-345. 32 Firth HV, Richards SM, Bevan AP et al: DECIPHER: Database of Chromosomal Imbalance and Phenotype in Humans Using Ensembl Resources. Am J Hum Genet 2009; 84: 524-533. 33 Gu W, Zhang F, Lupski JR: Mechanisms for human genomic rearrangements. Pathogenetics 2008; 1: 4. |
No hint is given that this text comes from another source. |
|
| [7.] Analyse:Ftp/Fragment 018 14 - Diskussion Zuletzt bearbeitet: 2014-12-19 07:45:12 SleepyHollow02 | Fragment, Ftp, Katzaki 2009, SMWFragment, Schutzlevel, Verschleierung, ZuSichten |
|
|
|
| Untersuchte Arbeit: Seite: 18, Zeilen: 14 ff. |
Quelle: Katzaki 2009 Seite(n): 21 f, Zeilen: 21: 9 ff.; 22: 1 ff. |
|---|---|
| 1.3.3 Application to detect the prevalence of mosaicism
Even though the effect of mosaicism on embryonic development and pregnancy outcome is not entirely clear, mosaic chromosomal imbalances have been shown to affect the development of in vitro-generated preimplantation embryos. [56] However, the detection of mosaicism in only 5% of aneuploid spontaneous miscarriages between 6-20 weeks gestation [57] and in only 12% of viable pregnancies screened by chorionic villus sampling (CVS) [58] [59] indicates that the incidence of mosaicism decreases through the first and second trimesters of pregnancy and is even rarer in live births. This dramatic reduction in mosaicism from the early stages of embryonic development through the late stages of clinically established pregnancies suggests that there is significant selection against mosaicism. Nevertheless, detecting low-level mosaicism for clinically significant chromosome abnormalities remained a pressing diagnostic challenge for conventional cytogenetic testing until the advent of aCGH. The first systematic study of mosaicism in a large cohort identified mosaicism in as [little as 3% of the cells on the basis of metaphase counts. [60] ] 56. Bielanska, M., S.L. Tan, and A. Ao, Chromosomal mosaicism throughout human preimplantation development in vitro: incidence, type, and relevance to embryo outcome. Hum Reprod, 2002. 17(2): p. 413-9. 57. Hassold, T., Mosaic trisomies in human spontaneous abortions. Hum Genet, 1982. 61(1): p. 31-5. 58. Ledbetter, D.H., et al., Cytogenetic results from the U.S. Collaborative Study on CVS. Prenat Diagn, 1992. 12(5): p. 317-45. 59. Wang, B.B., C.H. Rubin, and J. Williams, 3rd, Mosaicism in chorionic villus sampling: an analysis of incidence and chromosomes involved in 2612 consecutive cases. Prenat Diagn, 1993. 13(3): p. 179-90. 60. Ballif, B.C., et al., Detection of low-level mosaicism by array CGH in routine diagnostic specimens. Am J Med Genet A, 2006. 140(24): p. 2757-67. |
Even though the effect of mosaicism on embryonic development and pregnancy outcome is not entirely clear, mosaic chromosomal imbalances have been shown to affect the development of in vitro-generated preimplantation embryos.61 However, the detection of mosaicism in only 5% of aneuploid spontaneous miscarriages between 6-20 weeks gestation62 and in only 12% of viable pregnancies screened by chorionic villus sampling (CVS)63,64 indicates that the incidence of mosaicism decreases through the first and second trimesters of pregnancy and is even rarer in live births. This dramatic reduction in mosaicism from the early stages of embryonic development through the late stages of clinically established pregnancies suggests that there is significant selection against mosaicism. Nevertheless, detecting low-level mosaicism for clinically significant chromosome abnormalities remained a pressing diagnostic challenge for conventional cytogenetic testing until the advent of array-CGH. The first systematic study of mosaicism in a large cohort identified mosaicism in as little as 3% of the cells on the basis of metaphase counts.65
61 Bielanska M, Tan SL, Ao A: Chromosomal mosaicism throughout human preimplantation development in vitro: incidence, type, and relevance to embryo outcome. Hum Reprod 2002; 17: 413-419. 62 Hassold T: Mosaic trisomies in human spontaneous abortions. Hum Genet 1982; 61: 31-35. 63 Ledbetter DH, Zachary JM, Simpson JL et al: Cytogenetic results from the U.S. Collaborative Study on CVS. Prenat Diagn 1992; 12: 317-345. 64 Wang BB, Rubin CH, Williams J, 3rd: Mosaicism in chorionic villus sampling: an analysis of incidence and chromosomes involved in 2612 consecutive cases. Prenat Diagn 1993; 13: 179-190. 65 Ballif BC, Rorem EA, Sundin K et al: Detection of low-level mosaicism by array CGH in routine diagnostic specimens. Am J Med Genet A 2006; 140: 2757-2767. |
No hint is given that this text comes from another source. |
|
| [8.] Analyse:Ftp/Fragment 020 12 - Diskussion Zuletzt bearbeitet: 2014-12-19 15:42:08 SleepyHollow02 | Fragment, Ftp, Katzaki 2009, SMWFragment, Schutzlevel, Verschleierung, ZuSichten |
|
|
|
| Untersuchte Arbeit: Seite: 20, Zeilen: 12-18 |
Quelle: Katzaki 2009 Seite(n): 26, Zeilen: 20 ff. |
|---|---|
| The application of high-resolution genome analysis in research and clinical laboratories will uncover the genomic basis of many such disorders and will allow for better correlation of the many known CNVs with specific phenotypes. Although this promises to be a very challenging exercise, [79] [80] much work has already been initiated in cancer, neurological and neuropsychological conditions, infectious diseases, and others, suggesting that the clinical utility and applicability of such investigations cannot be too distant.
79. Lupski, J.R., Genomic rearrangements and sporadic disease. Nat Genet, 2007. 39(7 Suppl): p. S43-7. 80. Lupski, J.R., New mutations and intellectual function. Nat Genet, 2010. 42(12): p. 1036-8. |
The application of high-resolution genome analysis in research and clinical laboratories will uncover the genomic basis of many such disorders and will allow for better correlation of the many known CNVs with specific phenotypes. Although this promises to be a very challenging exercise,97 much work has already been initiated in cancer, neurological and neuropsychological conditions, infectious diseases, and others, suggesting that the clinical utility and applicability of such investigations cannot be too distant. 25
25 Bejjani BA, Shaffer LG: Clinical utility of contemporary molecular cytogenetics. Annu Rev Genomics Hum Genet 2008; 9: 71-86. 97 Lupski JR: Genomic rearrangements and sporadic disease. Nat Genet 2007; 39: S43-47. |
No hint is given that this text comes from another source. |
|
| [9.] Analyse:Ftp/Fragment 022 21 - Diskussion Zuletzt bearbeitet: 2014-12-19 15:50:57 SleepyHollow02 | Fragment, Ftp, Katzaki 2009, SMWFragment, Schutzlevel, Verschleierung, ZuSichten |
|
|
|
| Untersuchte Arbeit: Seite: 22, Zeilen: 21 ff. |
Quelle: Katzaki 2009 Seite(n): 27, Zeilen: 2 ff. |
|---|---|
| As we already mentioned before, many patients suffering from developmental disorders harbor submicroscopic deletions or duplications that, by affecting the copy number of dosage-sensitive genes or disrupting normal gene expression, lead to disease. However, many aberrations are novel or extremely rare, making clinical interpretation problematic and genotypephenotype correlations uncertain. Identification of patients sharing a genomic rearrangement and having phenotypic features in common leads to greater [certainty in the pathogenic nature of the rearrangement and enables new syndromes to be defined.] | As we already mentioned before, many patients suffering from developmental disorders harbor submicroscopic deletions or duplications that, by affecting the copy number of dosage-sensitive genes or disrupting normal gene expression, lead to disease. However, many aberrations are novel or extremely rare, making clinical interpretation problematic and genotype-phenotype correlations uncertain. Identification of patients sharing a genomic rearrangement and having phenotypic features in common leads to greater certainty in the pathogenic nature of the rearrangement and enables new syndromes to be defined. |
No hint is given that this text comes from another source. As we already mentioned before - maybe a scientific pluralis maiestatis? |
|