What Is Triple X Syndrome?
Triple X syndrome is a genetic
condition found in females only. About 1 in 1,000 girls have it.
Girls with triple X syndrome — also known as XXX syndrome, trisomy X, and
47,XXX, — might be taller than other girls. Other symptoms can include problems
with spoken language and processing spoken words, coordination problems, and weaker
muscles.
Most girls with triple X syndrome can grow up healthy, have normal sexual
development and fertility, and lead productive lives.
Depending on which symptoms a girl has and how severe they are, doctors may recommend
various treatments.
What Causes Triple X Syndrome?
Girls who have triple X syndrome are born with it. It's called triple X because
they have an extra X chromosome in most or all of their cells.
Usually, a person has 46 chromosomes in each cell, divided into 23 pairs, which
includes two sex chromosomes. Half of the chromosomes are inherited from the father
and the other half from the mother. The chromosomes contain genes, which determine
an individual's characteristics, such as eye color and height. Girls typically have
two X chromosomes (or XX), but girls with triple X syndrome have an extra X chromosome
(XXX).
Triple X is not caused by anything the parents did or did not do. The disorder
is a random error in cell division. This error can happen before conception in the
reproductive cells of the mother or the father, or early in the embryo's development.
When the extra chromosome is due to incorrect cell division in the embryo, a girl
may have a mosaic form of triple X syndrome. This means some of the
cells have an extra X chromosome, but not all do. Girls with this type of triple X
syndrome usually have fewer symptoms.
What Are the Signs & Symptoms of Triple X Syndrome?
Noticeable signs and symptoms of triple X syndrome can vary greatly. Some girls
have no obvious signs, while others have mild symptoms. Occasionally, the disorder
causes significant problems.
Girls with triple X syndrome can have some or all of these physical symptoms to
some degree:
- taller than average height (usually, very long legs)
- low muscle tone, or muscle weakness (called hypotonia)
- very curved pinky finger (called clinodactyly)
- widely spaced eyes (called hypertelorism)
Girls with triple X syndrome also may have delayed development of their social,
language, and learning skills. They also can have problems with reading and understanding
math, and may have mild delays with coordination.
What Problems Can Happen?
Girls with triple X syndrome may develop anxiety,
depression,
and attention deficit hyperactivity
disorder (ADHD). These problems might ease as they get older and reach adulthood.
Otherwise, treatment can help manage them.
Less often, girls might have abnormal development of the ovaries and/or uterus,
a delayed or early onset of puberty, and problems with fertility. Rarely, a girl may
develop kidney and heart problems, frequent urinary
tract infections (UTIs), stomach pain, constipation, flat feet, and an abnormally
shaped chest wall and ribcage (called pectus
excavatum).