Is Turner syndrome marked by a genetic abnormality?
Turner syndrome is characterized by an abnormality in the X chromosome. Normally females have two X chromosomes (and males have one X and one Y). In Turner syndrome, females often have only a single X chromosome. (This occurs in 60 percent of patients with Turner syndrome.) Patients may also have “cell line mosaicism”, meaning not all cells in the body have identical chromosomes. Normally all cells have the same chromosomes, but in some patients with Turner syndrome, some cells will have the normal XX pattern and some will have X0 (meaning only one X chromosome as opposed to the normal two chromosomes). There are a number of possible mosaic patterns. If a “Y” cell line is present, the patient is at higher risk for developing a particular type of cancer of the ovary and thus removal of the ovaries is recommended.
