WordNet

marked strangeness as a consequence of being abnormal (同)freakishness
behavior that breaches the rule or etiquette or custom or morality (同)irregularity
an abnormal physical condition resulting from defective genes or developmental deficiencies (同)abnormalcy
retardation sufficient to fall outside the normal range of intelligence (同)mental defectiveness
of or relating to cytogenetics (同)cytogenetical
the branch of biology that studies the cellular aspects of heredity (especially the chromosomes)

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〈U〉異常,変則 / 〈U〉異常なもの(事件)

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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2015/06/11 09:09:46」(JST)

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The three major single chromosome mutations; deletion (1), duplication (2) and inversion (3).

The two major two chromosome mutations; insertion (1) and Translocation (2).

A chromosome anomaly, abnormality, aberration, or mutation is a missing, extra, or irregular portion of chromosomal DNA.^[1] It can be from an atypical number of chromosomes or a structural abnormality in one or more chromosomes. Chromosome mutation was formerly used in a strict sense to mean a change in a chromosomal segment, involving more than one gene.^[2] A karyotype refers to a full set of chromosomes from an individual that can be compared to a "normal" karyotype for the species via genetic testing. A chromosome anomaly may be detected or confirmed in this manner. Chromosome anomalies usually occur when there is an error in cell division following meiosis or mitosis. There are many types of chromosome anomalies. They can be organized into two basic groups, numerical and structural anomalies.

Numerical disorders

This is called aneuploidy (an abnormal number of chromosomes), and occurs when an individual either is missing a chromosome from a pair (monosomy) or has more than two chromosomes of a pair (trisomy, tetrasomy, etc.).

In humans, an example of a condition caused by a numerical anomaly is Down Syndrome, also known as Trisomy 21 (an individual with Down Syndrome has three copies of chromosome 21, rather than two). Trisomy has been determined to be a function of maternal age.

An example of monosomy is Turner syndrome, where the individual is born with only one sex chromosome, an X.

Structural abnormalities

When the chromosome's structure is altered, this can take several forms:^[3]

Deletions: A portion of the chromosome is missing or deleted. Known disorders in humans include Wolf-Hirschhorn syndrome, which is caused by partial deletion of the short arm of chromosome 4; and Jacobsen syndrome, also called the terminal 11q deletion disorder.
Duplications: A portion of the chromosome is duplicated, resulting in extra genetic material. Known human disorders include Charcot-Marie-Tooth disease type 1A, which may be caused by duplication of the gene encoding peripheral myelin protein 22 (PMP22) on chromosome 17.
Translocations: A portion of one chromosome is transferred to another chromosome. There are two main types of translocations:
- Reciprocal translocation: Segments from two different chromosomes have been exchanged.
- Robertsonian translocation: An entire chromosome has attached to another at the centromere - in humans these only occur with chromosomes 13, 14, 15, 21, and 22.
Inversions: A portion of the chromosome has broken off, turned upside down, and reattached, therefore the genetic material is inverted.
Insertions: A portion of one chromosome has been deleted from its normal place and inserted into another chromosome.
Rings: A portion of a chromosome has broken off and formed a circle or ring. This can happen with or without loss of genetic material.
Isochromosome: Formed by the mirror image copy of a chromosome segment including the centromere.

Chromosome instability syndromes are a group of disorders characterized by chromosomal instability and breakage. They often lead to an increased tendency to develop certain types of malignancies.

Inheritance

Most chromosome abnormalities occur as an accident in the egg cell or sperm, and therefore the anomaly is present in every cell of the body. Some anomalies, however, can happen after conception, resulting in Mosaicism (where some cells have the anomaly and some do not). Chromosome anomalies can be inherited from a parent or be "de novo". This is why chromosome studies are often performed on parents when a child is found to have an anomaly. If the parents do not possess the abnormality it was not initially inherited; however it may be transmitted to subsequent generations.

Acquired chromosome abnormalities

Most cancers, if not all, carry chromosome abnormalities,^[4] with either the formation of hybrid genes and fusion proteins, deregulation of genes and overexpresson of proteins, or loss of tumor supressor genes (see the "Mitelman Database" ^[5] and the Atlas of Genetics and Cytogenetics in Oncology and Haematology,^[6]).

References

^ NHGRI. 2006. Chromosome Abnormalities
^ Rieger, R.; Michaelis, A.; Green, M.M. (1968). "Mutation". A glossary of genetics and cytogenetics: Classical and molecular. New York: Springer-Verlag. ISBN 9780387076683.
^ http://atlasgeneticsoncology.org/Educ/PolyMecaEng.html
^ http://atlasgeneticsoncology.org/Educ/Hempat_e.html
^ "Mitelman Database of Chromosome Aberrations and Gene Fusions in Cancer".
^ "Atlas of Genetics and Cytogenetics in Oncology and Haematology". atlasgeneticsoncology.org.

External links

Chromosome disorders at the US National Library of Medicine Medical Subject Headings (MeSH)

UpToDate Contents

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1. 血液悪性腫瘍における細胞遺伝子解析の一般的側面 general aspects of cytogenetic analysis in hematologic malignancies
2. 先天性の細胞遺伝学的異常 congenital cytogenetic abnormalities
3. 小頭症に対する臨床遺伝学的アプローチ microcephaly a clinical genetics approach
4. 急性骨髄性白血病における細胞遺伝学 cytogenetics in acute myeloid leukemia
5. 骨髄異形成症候群における細胞遺伝学および分子遺伝学 cytogenetics and molecular genetics of myelodysplastic syndromes

English Journal

Towards a turning point of neuroblastoma therapy.

Tonini GP, Nakagawara A, Berthold F.SourceItalian Neuroblastoma Foundation, IRCCS A.O.U. San Martino-IST, National Cancer Research Institute, Genoa, Italy. Electronic address: gptonini@gmail.com.
Cancer letters.Cancer Lett.2012 Dec 30;326(2):128-34. doi: 10.1016/j.canlet.2012.08.017. Epub 2012 Aug 23.
In 1983, the MYCN oncogene amplification was discovered in neuroblastoma cells and few years later its prognostic role was clearly demonstrated. The first European study, in which MYCN gene status is taken as prognostic factor for therapeutic decision, was released by SIOPEN and GPOH in 1995. Afterw
PMID 22922304

Molecular cytogenetic characterization of the first reported case of an inv dup (4p)(p15.1-pter) with a concomitant 4q35.1-qter deletion and normal parents.

Tassano E, Alpigiani MG, Salvati P, Gimelli S, Lorini R, Gimelli G.SourceLaboratorio di Citogenetica, Istituto Giannina Gaslini IRCCS, Genova, Italy.
Gene.Gene.2012 Dec 15;511(2):338-40. doi: 10.1016/j.gene.2012.09.083. Epub 2012 Sep 29.
Inverted duplications associated with terminal deletions are complex anomalies described in an increasing of chromosome ends. We report on the cytogenetic characterization of the first de novo inv dup del(4) with partial 4p duplication and 4q deletion in a girl with clinical signs consistent with "r
PMID 23031810

Japanese Journal

Der(2)t(2;11)(p21;q23), a Variant form of t(2;11), in Biphenotypic Acute Leukemia with T Lymphoid Lineage and M yeloid Lineage Differentiation

Miyazawa Yuri,Irisawa Hiroyuki,Matsushima Takafumi [他],Mitsui Takeki,Uchiumi Hideki,Saitoh Takayuki,Handa Hiroshi,Karasawa Masamitsu,Murakami Hirokazu,Tsukamoto Norifumi,Nojima Yoshihisa
北関東医学 62(3), 287-290, 2012-08-00
… Cytogenetic analysis revealed complex chromosomalabnormalities, including der(2)t(2;11)(p21;q23). … However, der(2)t(2;11)(p21;q23) anomaly persisted in most of metaphases.Fluorescence in situ hybridization (FISH)analysis with a probe for MLL did not detect the split signal.Forty-five cases of hematological disorder with t(2;11)(p21;q23) abnormality have been previouslyreported. …
NAID 40019415976

染色体線量評価の現状と今後の展望

吉田光明
放射線生物研究 47(2), 165-178, 2012-06-00
NAID 40019392842

A Case of Ambiguous External Genitalia in a Thoroughbred Male Horse with the 63,XO/64,XY Mosaic Karyotype

SATO Fumio,HIROTA Keiichi,TOZAKI Teruaki [他],ITO Katsumi,DHAKAL Pramod,TAYA Kazuyoshi,ENDO Yoshiro,MURASE Harutaka,NAMBO Yasuo
Journal of Veterinary Medical Science 74(10), 1327-1331, 2012
… A cytogenetic analysis revealed the 63,XO/64,XY mosaic karyotype (ratio 83:17). … These results add to our knowledge of chromosomal abnormality and information concerning disorders of sex development in the horse. …
NAID 130001879818

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リンク元	「chromosome aberration」「chromosomal aberration」「chromosome abnormality」「chromosomal abnormality」「chromosomal disorder」
関連記事	「abnormality」「cytogenetic」「cytogenetics」