Triple X Syndrome: Not What You Think

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It may sound like a psychological disorder describing a blue movie fixation, but triple X syndrome, also called trisomy X, is actually a genetic ailment. The “triple X” in this case does not refer to a movie rating, but rather the number of chromosomes.

As you may remember from your high school Biology, females normally have two X chromosomes in all of their cells, one from each parent. But one in every thousand women – those with triple X syndrome – have three. This third chromosome occurs as a result of a random error in cell division. This error can happen before conception or early in the embryo's development.

Exactly when the error occurs will determine the scope of the syndrome. In most cases, either the mother's egg cell or the father's sperm cell divides incorrectly, resulting in an extra X chromosome in the child. This random error is called “nondisjunction,” and results in all the cells in the child's body having the extra X chromosome.

If the extra chromosome results from an incorrect cell division caused by a random event early in the embryo's development, the condition is known as “mosaic,” and only some cells will have the extra X chromosome. Females with the mosaic form may have less obvious symptoms.

The symptoms for triple X syndrome vary, from none to developmental delays and learning disabilities. The most common symptom is a taller than average height with especially long legs. Other symptoms may include:

  • Delayed development of speech and language skills, as well as motor skills, such as sitting up and walking
  • Learning disabilities, such as dyslexia or difficulty with math
  • Problems with fine and gross motor skills, memory, judgment and information processing
  • Weak muscle tone
  • Abnormally curved pinky fingers
  • Behavior and emotional problems
  • Vertical folds of skin that cover the inner corners of the eyes or widely spaced eyes

The time to see a doctor is when you have concerns over your daughter's development. Triple X syndrome can only be diagnosed through genetic testing; that is, chromosome analysis using a blood sample.

There is no way to reverse the chromosome error that causes triple X syndrome, so any treatment prescribed will be focused upon managing the particular case's symptoms.