Fragile X & Autism

What is Fragile X Syndrome?

FXS is a genetic condition that causes intellectual disability, behavioural and learning challenges, and various physical characteristics. Though FXS occurs in both genders, males are more frequently affected than females, and generally with greater severity. The agreed upon prevalence of FXS is approximately 1 in 3,600–4,000 for males and 1 in 4,000–6,000 for females.

No one individual will have all the features of FXS:

• Behavioural characteristics?include ADD, ADHD, social anxiety, hand-biting and/or flapping, poor eye contact, sensory disorders, increased risk for aggression, and autism and autistic-like behaviours.
• Intellectual disabilities?include a range from moderate learning disabilities to more severe intellectual disabilities.
• Physical features?may include large ears, long face, soft skin, and large testicles in post-pubertal males.
• Connective tissue problems?may include ear infections, flat feet, high arched palate and joint hypermobility (such as Hypermobile Ehlers Danlos Syndrome or hEDS).
• Disposition: In contrast to the generally perceived profile of many autistic individuals (many of us mask our symptoms ), FXS individuals tend to be very social and friendly, have excellent imitation skills, have a strong visual memory/long term memory, like to help others, are nice, thoughtful people and have a wonderful sense of humour.

Cause of FXS

Fragile X syndrome is caused by the expansion or lengthening of the FMR1 gene on the X chromosome, known as a gene mutation. The X chromosome is one of two sex-determining chromosomes. When the gene lengthens it switches off production of a protein that is involved in brain development and other functions.

The Diagnosis

FXS is usually diagnosed through genetic testing using the FMR1 DNA Test (sometimes called the Fragile X DNA Test) .

Who Should Have Fragile X Testing?

In the UK, many young children with signs of intellectual disabilities, global developmental delay, speech and language delay, autism or learning disabilities are often routinely tested for Fragile X before considering other diagnoses such as Smith-Magenis Syndrome or Fetal Anticonvulsant Syndrome.

Treating FXS

Like autism, there is no medical treatment or cure for FXS. Interventions and therapies are focused more around preventative behavioural interventions , speech and language therapy , sensory integration and intensive interaction . For most individuals a combination of some or all of these therapies can improve the lives of affected individuals and their families. Given the proper education, therapy, and support, all individuals can make progress.

Similarities & Differences

FXS vs. ASD

Characteristics that have been found to differ between the FXS behavioural phenotype and ASD include:

• The frequency of intellectual disability is higher in FXS than ASD. Most males and about a third of females with FXS have intellectual disability, while only about 40% of individuals with ASD have intellectual disability.
• Motor coordination deficits are worse in FXS than ASD.
• Autistic individuals are more likely to show greater deficits in receptive language than expressive language, while individuals with FXS tend to show the opposite pattern.
• Interest in socialising is higher in FXS in general than ASD (although limited by anxiety and avoidance).
• Imitation skills are better in FXS than ASD when level of intellectual impairment is controlled.

FXS+ASD vs. FXS Alone

Characteristics of individuals with FXS who meet criteria for ASD (FXS+ASD) compared to individuals with FXS alone include:

• Less developed language skills, particularly receptive skills.
• Lower non-verbal cognition and IQ scores.
• Lower adaptive skills.
• More severe overall behavioural problems.
• Reduced interest in and motivation for social interaction or a failure to attend to social information that might promote appropriate social behaviour.

Consequently, from educational and vocational viewpoints, individuals with FXS+ASD face similar but more severe challenges than children with FXS.

When it comes to diagnosing Fragile X syndrome, there is good news and bad news. The good news is that more children than ever are being accurately diagnosed with Fragile X syndrome at an early age. The bad news is that there is a lot of confusion among parents, and even professionals, about the meaning of Fragile X in relation to other types of diagnoses that a child receives.

Further information on Fragile X Syndrome can be found in the UK at :

https://www.fragilex.org.uk/