The Principles of Clinical Cytogenetics - Extra Materials - Springer

38 Avirachan Tharapel
Fig. 5. (continued)
Here, we have a patient with Klinefelter syndrome who has an acquired X chromosome in his tumor
cells. The letter “c” is placed next to XXY to show that the patient’s sex chromosome complement is
XXY and not XY or XXXY.
46,Xc,+X
This is a Turner syndrome patient (45,X) with gain of an X chromosome in her tumor cells.
Numerical Abnormalities of the Autosomes
The situation here is similar to that involving the sex chromosomes, with the exception that (+)
and (–) signs are used to designate constitutional abnormalities:
47,XY,+18 Male with trisomy 18
48,XX,+18+21 Female with both trisomy 18 and trisomy 21
45,XY,–21 Male with monosomy 21
46,XY,+21c,–21 Male trisomy 21 patient with loss of one chromosome 21 in his tumor cells
48,XX,+21c,+21 Female with trisomy 21 and gain of an additional chromosome 21 in her tumor cells
Mosaics and Chimeras
An individual with two or more cell types, differing in chromosome number or structure is either
a mosaic or a chimera. If the two cell types originated from a single zygote, the individual is a mosaic
(mos). If the cell types originated from two or more zygotes that subsequently fused, the individual is
a chimera (chi). In designating mosaic or chimeric karyotypes, a slash (/) is used to separate the cell
lines. The actual number of cells detected in each clone can be given within square brackets [ ]. The