Mosaic Turner syndrome
mos 45,X[12]/46,XX[18]
Also known as: 45,X/46,XX, mosaic 45 X
This karyotype shows mosaic Turner syndrome, with two cell lines: 45,X and 46,XX. The bracketed numbers are the cells counted in each line, and mosaic forms are often milder than a non-mosaic 45,X.
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![Karyotype of Mosaic Turner syndrome (mos 45,X[12]/46,XX[18])](karyogram.png)
What the notation means
45,X[12]12 cells
45- total chromosome count (normal is 46)
X- sex chromosomes: a single X (monosomy X)
[12]- seen in 12 cells counted for this clone
46,XX[18]18 cells
46- total chromosome count (the normal human number)
XX- sex chromosomes: two X (usual female karyotype)
[18]- seen in 18 cells counted for this clone
Clinical notes
Turner syndrome (45,X and variants)
Loss of all or part of the second sex chromosome. 45,X (monosomy X) is classic; variants include an isochromosome i(Xq), a ring r(X), an idic(Y), and 45,X mosaicism (e.g. 45,X/46,XX). Short stature, ovarian dysgenesis/streak gonads, webbed neck, coarctation/bicuspid aortic valve, lymphedema.