Fragile X Syndrome

Fragile X syndrome is the most common known cause of inherited intellectual disability, affecting around 1 in 4000 males and about 1 in 6,000 females.

It is one of a family of conditions caused by a mutation (change) to the FMR1 gene on the X chromosome. The FMR1 gene is responsible for producing a protein important for brain development. When the gene lengthens through the mutation, it switches off production of that protein involved in brain development and other functions.

Fragile X syndrome can cause a wide range of difficulties with learning, as well as social, language, attentional, emotional, behavioural and medical problems. The effects of Fragile X syndrome on an individual vary and can range from mild to severe. Men and boys commonly appear more severely affected by Fragile X syndrome, but women and girls may also be severely affected.

Fragile X syndrome is also the most common known single-gene cause of autism spectrum disorder. Up to 50% of males with Fragile X syndrome will meet the criteria for autism spectrum disorder. Approximately 2% of people who meet the criteria for a diagnosis of autism spectrum disorder have been found to have Fragile X syndrome.

It is estimated that in Australia, each week one child is born with Fragile X syndrome, and 20 children are born who are carriers of the FMR1 gene premutation.

While there is as yet no cure for Fragile X syndrome, there are a range of treatment interventions and management strategies that are of great benefit.

chromosome image

Photo credit: Genome Research Limited

To learn more:

Understanding Fragile X

Video produced by Fragile X Association of Australia

About Fragile X syndrome

Video produced by Fragile X Society UK (7 minutes)

Fragile X syndrome 

Article from Medical Observer journal


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Your generous donation will help FXAA ensure people living with Fragile X are connected, included, understood and empowered. Specifically, your donation (no matter how big or small) will help us maintain and deliver support and connections to the Fragile X community: 1. Counselling support 2. FXAA Helpline - available 5 days per week 3. Webinar program 4. Peer connection and referrals 5. Advocacy work – for example, our Fragile X Care | Adults & Ageing study that we’re undertaking collaboratively with the Centre for Disability Studies is the first Australian study on the support needs, health & wellbeing of adults with Fragile X Syndrome as they age. All support is sincerely appreciated and helps us make a difference.

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