People with fragile X syndrome (or fragile X) have intellectual disability, behavioural and learning challenges as well as certain physical characteristics. Fragile X is the most common inherited cause of intellectual disability, and also the most common genetic cause of autism. It affects around 1 in 3600 males and around 1 in 6000 females.

About fragile X syndrome

Fragile X syndrome gets its name from the X chromosome – 1 of the 2 chromosomes that determine our gender.

Chromosomes carry our DNA – the chemical that has the information for our features. Sometimes the X chromosome develops a fault – its DNA changes, or mutates.

Some people are carriers of this faulty gene but are fairly healthy themselves. Some people with this faulty gene will be born showing the symptoms of fragile X syndrome.

Fragile X syndrome is more common and more severe in males than in females. This is because males have one X chromosome and one Y chromosome, while females have two X chromosomes, only of which one is changed.

Symptoms of fragile X

Some people with fragile X have very few problems, while others have significant problems. The main symptoms of fragile X are:

• speech and language delays
• intellectual disabilities and learning difficulties
• anxiety and related problems such as obsessive-compulsive disorder
• problems with coordination
• physical features such as low muscle tone or a heart murmur
• behavioural and emotional problems, shyness, aggression and mood swings
• attention deficit hyperactivity disorder or autism spectrum disorder

Women with fragile X or who carry the gene might experience early menopause.

Male carriers (and occasionally females) might experience fragile X tremor ataxia syndrome. The symptoms are similar in some ways to those of Parkinson’s disease.

Can fragile X syndrome be detected during pregnancy?

Yes. If you have a family history of fragile X, you can be tested before becoming pregnant to see if you are at risk of passing on the mutated X chromosome to your baby. That is, to see if you are a carrier.

A genetic counsellor can help you explore ways of having a healthy baby if you are found to be a carrier of the fragile X gene.

If you are a carrier, your baby can be tested in pregnancy using either amniocentesis or chorionic villous sampling.

If you have a child of any age showing symptoms of fragile X, your doctor can ask for a DNA blood test to see if they have the condition. Your child can then get the help they need.

What if my child has fragile X syndrome?

You may need support as you deal with the news.

If you are pregnant, you need to work out whether to have the baby or consider terminating the pregnancy. You can ask your doctor to refer you to a genetic counsellor who specialises in helping people in your situation. And you can call Pregnancy, Birth and Baby for advice and support.

It’s a good idea to find out as much as you can about fragile X syndrome. The Fragile X Association of Australia provides information and real-life stories about living with the condition.

There is no cure for fragile X but there are effective treatments. You can help your child reach their potential by getting help for them as soon as possible after diagnosis. This is called early intervention. A team of different specialists work together to look after your child’s educational, behavioural and medical needs. This team may also include a psychologist to help your family work through some of the difficulties of living with a person with a disability.

What assistance is available?

Raising a child with a disability is not easy but help is available. The Fragile X Association provides a list of government support programs. You can also call Pregnancy, Birth and Baby on 1800 882 436 for advice and emotional support.