Small supernumerary marker chromosome: Difference between revisions

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Introduction

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Human Chromosomes: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | X | Y

Idiogram Chromosome Banding - The term refers to the light and dark pattern, seen after staining with a dye, of individual chromosomes identified in metaphase. It is only in meiosis and mitosis during metaphase that chromosomes can be easily identified, during the normal cell life (interphase) the chromosomes are unravelled and distributed within the nucleus in chromosome territories. A band is that part of a chromosome which is clearly distinguishable from nearby regions by appearing darker or brighter with one or more banding techniques.

Human Idiogram: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | X | Y

Genetic abnormality locations: 1-4 | 5-8 | 9-12 | 13-16 | 17-20 | 21-XY | sSMC

Links: Genetics | Abnormal Development - Genetic

Cite this page: Hill, M.A. (2024, April 19) Embryology Small supernumerary marker chromosome. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/Small_supernumerary_marker_chromosome

What Links Here?

Small supernumerary marker chromosomes and uniparental disomy have a story to tell

J Histochem Cytochem. 2011 Sep;59(9):842-8. doi: 10.1369/0022155411412780. Epub 2011 Jun 14

Liehr T, Ewers E, Hamid AB, Kosyakova N, Voigt M, Weise A, Manvelyan M. Source Jena University Hospital, Institute of Human Genetics, Jena, Germany. i8lith@mti.uni-jena.de

Abstract

Small supernumerary maker chromosomes (sSMC) and uniparental disomy (UPD) are rare, and a combination of both is rarely encountered. Accordingly, only 46 sSMC cases UPD have been reported. Despite of its rareness, UPD has to be considered, especially in prenatal cases with sSMC. Here, the authors reviewed all sSMC cases with UPD (sSMC(U+)) and compared them to sSMC without UPD (sSMC(U-)), which resulted in the following correlations: 1) every sSMC, irrespective of its chromosomal origin, may be principally connected with UPD; 2) mixed hetero- and iso-UPD (hUPD/iUPD) can be observed most often in sSMC(U+) cases followed by complete iUPD, complete hUPD, and segmental iUPD; 3) UPD of chromosomes 6, 7, 14, 15, 16, and 20 is most often reported in sSMC(U+); 4) maternal UPD was approximately nine times more frequent than paternal UPD; 5) if mosaic with a normal cell line, acrocentric-derived sSMC had a three times higher chance of occurrence than the corresponding nonmosaic sSMC cases; 6) UPD in connection with a parentally inherited sSMC is, if existent at all, a rare event; and 7) the gender type and shape of sSMC had no effect on UPD formation. Overall, sSMC(U+) cases may have a story to tell about chromosome number control mechanisms in early embryogenesis.

PMID 21673185

Handling small supernumerary marker chromosomes in prenatal diagnostics

Expert Rev Mol Diagn. 2009 May;9(4):317-24. doi: 10.1586/erm.09.17.

Liehr T, Ewers E, Kosyakova N, Klaschka V, Rietz F, Wagner R, Weise A. Source Jena University Hospital, Institute of Human Genetics and Anthropology, Jena, Germany.

Abstract

Small supernumerary marker chromosomes (sSMCs) are structurally abnormal chromosomes that cannot be thoroughly characterized by conventional banding cytogenetics and are equal in size or smaller than chromosome 20. They are present in 0.075% of prenatal cases and, overall, approximately 3 million people worldwide are carriers of a sSMC. In prenatal cases with ultrasound abnormalities, sSMCs are found in up to approximately 0.2% of the cases. First described in 1961, it is now known that sSMCs have no phenotypic effects in approximately 70% of de novo cases. Nonetheless, in at least 30-50% of prenatally detected sSMC cases, the pregnancy is terminated; that is, for a certain percentage of potentially healthy children with a sSMC, an abortion is induced. This situation can only be improved by providing increased amounts of and more reliable information on sSMCs. This article provides an overview on current state-of-the-art technologies and how sSMC analysis can be optimized in prenatal diagnostics.

PMID 19435454

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Cite this page: Hill, M.A. (2024, April 19) Embryology Small supernumerary marker chromosome. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/Small_supernumerary_marker_chromosome

What Links Here?

@@ Line 15: / Line 15: @@
 Source
 Jena University Hospital, Institute of Human Genetics, Jena, Germany. i8lith@mti.uni-jena.de
 Abstract
 Small supernumerary maker chromosomes (sSMC) and uniparental disomy (UPD) are rare, and a combination of both is rarely encountered. Accordingly, only 46 sSMC cases UPD have been reported. Despite of its rareness, UPD has to be considered, especially in prenatal cases with sSMC. Here, the authors reviewed all sSMC cases with UPD (sSMC(U+)) and compared them to sSMC without UPD (sSMC(U-)), which resulted in the following correlations: 1) every sSMC, irrespective of its chromosomal origin, may be principally connected with UPD; 2) mixed hetero- and iso-UPD (hUPD/iUPD) can be observed most often in sSMC(U+) cases followed by complete iUPD, complete hUPD, and segmental iUPD; 3) UPD of chromosomes 6, 7, 14, 15, 16, and 20 is most often reported in sSMC(U+); 4) maternal UPD was approximately nine times more frequent than paternal UPD; 5) if mosaic with a normal cell line, acrocentric-derived sSMC had a three times higher chance of occurrence than the corresponding nonmosaic sSMC cases; 6) UPD in connection with a parentally inherited sSMC is, if existent at all, a rare event; and 7) the gender type and shape of sSMC had no effect on UPD formation. Overall, sSMC(U+) cases may have a story to tell about chromosome number control mechanisms in early embryogenesis.
 PMID 21673185
+===Handling small supernumerary marker chromosomes in prenatal diagnostics===
+Expert Rev Mol Diagn. 2009 May;9(4):317-24. doi: 10.1586/erm.09.17.
+Liehr T, Ewers E, Kosyakova N, Klaschka V, Rietz F, Wagner R, Weise A.
+Source
+Jena University Hospital, Institute of Human Genetics and Anthropology, Jena, Germany.
+Abstract
+Small supernumerary marker chromosomes (sSMCs) are structurally abnormal chromosomes that cannot be thoroughly characterized by conventional banding cytogenetics and are equal in size or smaller than chromosome 20. They are present in 0.075% of prenatal cases and, overall, approximately 3 million people worldwide are carriers of a sSMC. In prenatal cases with ultrasound abnormalities, sSMCs are found in up to approximately 0.2% of the cases. First described in 1961, it is now known that sSMCs have no phenotypic effects in approximately 70% of de novo cases. Nonetheless, in at least 30-50% of prenatally detected sSMC cases, the pregnancy is terminated; that is, for a certain percentage of potentially healthy children with a sSMC, an abortion is induced. This situation can only be improved by providing increased amounts of and more reliable information on sSMCs. This article provides an overview on current state-of-the-art technologies and how sSMC analysis can be optimized in prenatal diagnostics.
+PMID 19435454
 {{Glossary}}