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 their cells.

Usually, a person has 46 chromosomes in each cell, divided into 23 pairs, which includes two sex chromosomes. Half 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 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 ones. Occasionally, the disorder causes significant problems.

Girls with triple X syndrome can have some or all of these physical signs 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).

How Is Triple X Syndrome Diagnosed?

Many girls with triple X syndrome are healthy and have no obvious symptoms. So sometimes the condition isn't diagnosed or is only found while a doctor checks for a different issue.

Often triple X syndrome is found because parents talked with a doctor about concerns with their daughter's development. This can help girls receive a diagnosis early. Research has shown that early interventions and treatments are more effective.

To diagnose triple X syndrome, doctors do a blood test to look for the extra X chromosome. Before birth, the condition may be found through  karyotype test or noninvasive prenatal testing (NIPT). NIPT is done on the fluid surrounding the fetus, tissue from the placenta, or the blood from the mother. After birth, doctors can make a diagnosis with a karyotype or with a microarray test from the baby.

How Is Triple X Syndrome Treated?

There is no cure for triple X syndrome, but treatments can help with specific symptoms.

Finding services early is important and can greatly increase how well they help girls live a healthier, more productive life. Options vary greatly depending on how old a girl was when she was diagnosed, whether she has noticeable symptoms, and the severity of those symptoms.

Treatments can include:

Regular doctor visits. At periodic visits, a doctor can monitor a girl's development for delays, social and language disabilities, or health problems and treat these promptly.

Educational support services. Educational support can teach girls ways to keep pace in school. Some girls might be eligible for an individualized educational program (IEP) or 504 education plan, which are designed to help children with specialized needs.

Early intervention services. It can be very helpful and often more effective for a girl to have speech, occupational, physical, or developmental therapy in the early months of life or as soon as concerns are found.

Speech therapy and physical therapy can improve a girl's speaking, reading, and writing skills and can help increase strength and coordination. Occupational therapy and behavioral therapy can help her develop more confidence and interact better with other children.

Counseling. The whole family can benefit from counseling to better understand triple X syndrome and help a girl who has it to live a productive life.

Early inventions should be considered at infancy for physical therapy, at 15 months for speech delay, at 1st grade for reading and learning issues, and at 3rd grade for anxiety or depression.

What Else Should I Know?

Girls with triple X syndrome can develop speech, learning, or social challenges at a young age. This can make them more likely to have low self-esteem and lead to school or social problems.

If your daughter has trouble making friends or struggles at school, talk to your doctor or the principal or school counselor. Counseling and therapy can teach your daughter practical skills to help her make friends and feel more confident in school, and educational services can help your daughter do well in school.

Talk to your doctor if you have any concerns about your daughter's physical and emotional development.

Despite physical differences and other problems, with the right medical care, early intervention, and ongoing support, a girl with triple X syndrome can lead a normal, healthy, and productive life.