This is an inactivated X chromosome in the form of tightly-coiled heterochromatin that appears as a discrete, recognisable entity on light microscopy.
Its presence can be used in the sexing of a baby; it is searched for in liquor obtained by amniocentesis, or in cells derived from chorionic villus sampling.
Annotations allow you to add information to this page that would be handy to have on hand during a consultation. E.g. a website or number. This information will always show when you visit this page.