Turner syndrome
45,X
Also known as: Monosomy X, 45 X
45,X is the karyotype of Turner syndrome, in which a single X is present and the second sex chromosome is missing. Short stature and ovarian insufficiency are characteristic, and loss of the SHOX gene drives much of the growth phenotype.
Open in the interactive visualizer →
What the notation means
45- total chromosome count (normal is 46)
X- sex chromosomes: a single X (monosomy X)
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.