Karyotypes - Various

© 2009 NHS National Genetics Education and Development Centre

Supporting Genetics Education for Healthwww.geneticseducation.nhs.uk

Karyotype imagesThis PowerPoint file contains a number of images of karyotypes that may be useful for teaching of genetics concepts.

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total number of chromosomes, sex chromosome constitution,

anomalies/variants.

46,XY47,XX,+2147,XXX69,XXY45,XX,der(13;14)(q10;q10)46,XY,t(2;4)(p12;q12)46,XX,del(5)(p25)46,XX,dup(2)(p13p22)46,XY,inv(11)(p15q14)46,XY,fra(X)(q27.3)46,XY/47,XXY

The Karyotype: an international description



total number of chromosomes, sex chromosome constitution,

anomalies/variants.

46,XY47,XX,+21 Trisomy 21 (Down syndrome)47,XXX Triple X syndrome69,XXY Triploidy

45,XX,der(13;14)(p11;q11) Robertsonian translocation

46,XY,t(2;4)(p12;q12) Reciprocal translocation

46,XX,del(5)(p25) Deletion tip of chromosome 546,XX,dup(2)(p13p22) Duplication of part of

short arm Chr 246,XY,inv(11)(p15q14) Pericentric inversion

chromosome 1146,XY,fra(X)(q27.3) Fragile X syndrome46,XY/47,XXY Mosaicism normal/Klinefelter

syndrome

The Karyotype: an international description



Fig. 2.5 ©Scion Publishing LtdRedrawn from ISCN 2005 with permission from S. Karger AG, Basel.

Nomenclature of cytogenetic bands.The ideograms show ideal G-banding patterns at 550 band resolution. Major bands are labelled 1,2,3, etc., going from centromere to telomere.Major band 11q1 (11q means the long arm of chromosome 11, 11p the short arm) is divided into sub-bands 11q11 – 11q14, and at the highest resolution 11q14 splits into 11q14.1 – 11q14.3.



Fig. 2.9 ©Scion Publishing Ltd




Karyotype showing trisomy 21 (47,XX,+21)




Karyotype of Isabel Ingram. Although Isabel will never be able to have children normally, treatment with estrogens can allow her to develop normal secondary sex characteristics and greatly assist her personal and social life. Modern reproductive technology has allowed some Turner syndrome patients to bear children using donor eggs. Treatment with growth hormone can result in improved growth and final height.




G-banded karyotypes of Ellen’s chromosomes. There is a balanced translocation. Chromosomes 1 and 22 have exchanged segments (arrows). The translocation is described as 46,XX,t(1:22)(q25;q13)




G-banded karyotype of baby Elizabeth. She has inherited Ellen’s normal chromosome 1 but her translocated chromosome 22 (arrow). She is trisomic for the portion of chromosome 1 distal to 1q25, the translocation breakpoint, and monosomic for chromosome 22 distal to 22q13.




How the 1;22 translocation in Ellen Elliot originated. Chromosome 1 and 22 broke at the positions indicated by the arrows, and the cell’s DNA repair machinery rejoined the ends to form the two derivative chromosomes as shown. The derivative chromosomes are labelled der(1) and der(22).




A Robertsonian translocation. The inset shows how this common type of chromosome abnormality arises. The short arms of all the acrocentric chromosomes (13, 14, 15, 21, 22) contain similar DNA. Inappropriate recombination between two non-homologous chromosomes produces the fusion chromosome, which functions as a normal single chromosome in mitosis. The small acentric fragment comprising the two distal short arms is lost.




22q11 metaphase FISH. The green spots are a control probe, used to identify the two copies of chromosome 22 and confirm that hybridization has taken place. The red spots are the TUPLE1 probe. Only one of the two copies of chromosome 22 contains the sequence that hybridizes to this probe.




Interphase FISH test for trisomy 21. The chromosome 21 probe is labelled with a red fluorochrome and a control probe (for chromosome 18) is labelled in green. The two green dots show that the hybridization has worked for this cell, and the three red dots show that there are three copies of chromosome 21. The clinical report is based on examining a large number of cells. For prenatal diagnosis a mix of differently coloured probes from chromosomes 13, 18, 21, X and Y is often used.




Array-CGH result on the patient shown in Figure 4.3. The whole genome was surveyed, but only results for the probes from chromosome 12 are shown. There is a duplication involving 39 contiguous clones from 12q24.1.



47,XX,+21



47,XX,+13



47,XX,+18



45,X



47,XXY



47,XYY



45,XX,der(14;21)(q10;q10)



46,XX,t(4;15)(q2?1.3;q13)



46,XX,t(9;22)(q34;q11)



ish der(9)(ABL-),der(22)(BCRsp+conABLsp+,ABLsp+,BCRsp+)



46,Y,fra(X)(q27.3)



Fragile X Chromosome



47,XX,+?mar



46,X,r(X)



ins(22;9)(q11;q13q34)



46,XY.ish del(15)(q11.2q11.2)(SNRPN-)



46,XY.ish del(15)(q11.2q11.2)(SNRPN-)



46,XX.ish del(22)(q11.2q11.2)(TUPLE1-)



46,XX.ish del(22)(q11.2q11.2)(TUPLE1-)



46,X,del(X)(p21.1)



46,XX,del(4)(p15.2p16.?2)



ish del(7)(q11.23q11.23)(ELN-)

Williams syndrome





Trisomy 21: 47,XX,+21three separate copies of chromosome 21



Three copies of all the chromosomes: triploidy



Different chromosome banding resolutions can resolve bands, sub-bands and sub-sub-bands

Chromosome 1

Human chromosome banding patterns seen on light microscopy



FISH - fluorescence in situ hybridisation



Example of FISH



Trisomy 21 amniocyte



Chromosomes seen through a microscope

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Karyotypes - Various