What are the features of triple X syndrome?

Only one X chromosome is active at any time in each female cell, thus triple X syndrome often does not cause medical issues or unusual physical features.

The features of triple X syndrome can vary widely and it is important to note that not all the features described will be seen in your child.

Some girls and women with triple X syndrome have minimal or no symptoms.

• Growth. Slightly taller stature.
• Physical features. Slightly smaller head, epicanthal folds (vertical folds of skin that comes across the inner angle of the eye) and clinodactyly (abnormally curved little finger).
• Learning.

  The majority of people with triple X syndrome have intelligence within the normal range. Some may have developmental issues such as delayed language or motor skills.
  
  Some may also experience behavioural and emotional difficulties.

Other medical problems may include:

• Cardiovascular (heart and blood vessels). Congenital heart disease (occurs in 0.8% – similar to population prevalence numbers).
• Endocrine. Delayed or early puberty. However, most girls and women with triple X syndrome have normal pubertal development and can conceive children.
• Kidney. Structural abnormalities of the kidney can occur, although it is rare.

It is important to note that although there may be certain differences between girls with triple X syndrome and girls with two X chromosomes, most of these differences are what is often found as normal variation among individuals.

Most girls and women with triple X syndrome lead normal lives. They go to mainstream schools, have jobs and children and live to an old age.