Fragile X Syndrome

What is Fragile X syndrome?

Fragile X syndrome is a genetic disorder. It is most often passed on from a parent to a child at the time the child is conceived. The disorder causes intellectual and developmental disabilities. This means it affects a person’s learning and physical growth. It also affects behavior and being able to relate to other people. The symptoms of Fragile X syndrome can be mild or moderate. It affects both girls and boys; however, it is often milder in girls.

Symptoms of Fragile X syndrome

There are many symptoms that go along with Fragile X syndrome. These include:

• Developmental: Many children have delays in sitting, crawling, walking, and speech in early childhood. The delays grow as the child gets older.
• Intellectual: School-aged children are below grade level in reading, math, and other subjects. They have trouble learning new things and could have mild to severe intellectual disability.
• Behavioral: They often have behavior problems. These could include trouble paying attention or being afraid or anxious. Both boys and girls may be shy or aggressive. They may also have social challenges. These could include difficulties making eye contact and interacting with others.
• Speech and language: Boys especially may have problems speaking clearly, stuttering, or leaving out parts of words. Some children have a delay in talking. A few may never talk at all.
• Sensory: Many people are sensitive to noise, light, or other sensory information.

A person diagnosed with Fragile X syndrome may have certain physical features, as well. These include:

• Larger-than-normal ears, jaw, and forehead
• A long, narrow face
• Flat feet
• Unusually flexible fingers

Men who have Fragile X syndrome may have larger-than-normal testicles after puberty. Women may experience infertility and enter menopause earlier than normal. Both men and women with Fragile X syndrome can have tremors (shaking) and difficulty with coordination. Some people will experience seizures.

What causes Fragile X syndrome?

Fragile X syndrome is caused by a problem with one of your genes. The normal gene makes a protein that is needed for brain development. But when there is a problem with that gene, it has trouble making the protein. This causes the symptoms that come with the disorder.

Most of the time, children inherit the gene from their parents. That is how Fragile X syndrome is passed on. However, it is possible to have Fragile X even if a child’s parents don’t have the Fragile X gene.

How is Fragile X syndrome diagnosed?

Some parents notice the developmental delays in their child and see their doctor. This leads to testing. A simple blood test can detect the Fragile X gene in your child any time after he or she is born. That confirms the diagnosis. Most children are diagnosed between the ages of 2 and 4.

If you suspect or know either parent has the Fragile X gene, prenatal testing can determine if the baby has the gene before it is born. This could include amniocentesis or chorionic villus sampling. Prenatal testing can help families prepare for a baby with Fragile X syndrome so they can start treatment as early as possible. But most parents don’t know they carry the gene, so prenatal testing is uncommon.

Can Fragile X syndrome be prevented or avoided?

Since Fragile X syndrome is a genetic disorder, it cannot be prevented or avoided.

Fragile X syndrome treatment

There is no cure for Fragile X syndrome. Certain therapies can help with the symptoms of the disorder. This includes physical, occupational, and speech therapy. Special education services can help with academic and learning challenges. They also can help with behavior. A young child’s brain is still growing. So, the earlier a child with Fragile X syndrome receives therapy, the better.

Living with Fragile X syndrome

Living with Fragile X syndrome is similar to living with any type of intellectual disability. Therapies and special education are designed to help the person to be as independent as possible. Independence depends on the severity of the diagnosis. For mild cases, the earlier the person receives therapy, the better their chances of being independent as they become an adult.

Questions to ask your doctor

• If I carry the Fragile X syndrome gene, how likely is it I will pass it on to my child?
• If I have one child with Fragile X syndrome, am I at a higher risk of having other children with the disease?
• If I notice delays in my child’s development, how long should I wait before seeing a doctor?
• Are there any medical conditions associated with Fragile X syndrome (heart, hearing, vision)?

Resources

Centers for Disease Control and Prevention, Facts About Fragile X Syndrome

Eunice Kennedy Shriver National Institute of Child Health and Human Development, Fragile X Syndrome

National Fragile X Foundation, Fragile X Syndrome

U.S. National Library of Medicine, Fragile X Syndrome