Fragile X Syndrome: Care Staff Guide to Inheritance and Support

Fragile X syndrome is the most common inherited cause of learning disability, and it affects people in different ways depending on their sex and genetic profile. Care and support staff may work with people who have fragile X syndrome, but also with relatives who carry a related change and who can develop other health conditions later in life. This guide, based on the NHS Genomics Education Programme knowledge hub, explains the key facts and how staff can support people well. It sits alongside our guides to Oliver McGowan mandatory training, ataxia and essential tremor.

What is fragile X syndrome?

The NHS genomics source describes fragile X syndrome as an X-linked genetic condition causing intellectual disability and distinctive physical features. It is caused by a change in the FMR1 gene on the X chromosome, where a repeating section of DNA expands. More than 200 repeats is described as the full mutation.

How it is inherited

Because the gene is on the X chromosome, inheritance differs between men and women. The source says that a mother who carries the full mutation has a 50 per cent chance of passing it on to each child, and that a father with the change passes it to all of his daughters but none of his sons. The size of the repeat can also grow from one generation to the next. Genetic counselling is available through NHS genetic services for families who have questions.

Features of fragile X syndrome

• Learning disability: usually moderate to severe in males. About half of females have mild to moderate learning disability, and there is variation because of how the X chromosomes are used in the body's cells.
• Social communication and behaviour: the source reports autism spectrum disorder in about 50 to 70 per cent of cases.
• Physical features: these can include a long, thin face, a prominent chin, large ears, a larger head, joint hypermobility and, in males after puberty, enlarged testes.

Every individual is unique, and some people have few physical signs. Management is complex and delivered by a multidisciplinary team, which can include paediatric, genetic, speech and language, educational and mental health professionals.

Carriers and the premutation

People with 55 to 200 repeats are described as premutation carriers. They do not have fragile X syndrome but can develop other conditions. The source explains that fragile X-associated tremor/ataxia syndrome (FXTAS), which causes tremor and balance problems later in life, affects 40 to 75 per cent of male carriers and 16 to 20 per cent of female carriers. Fragile X-associated primary ovarian insufficiency (FXPOI), which can cause early menopause and reduced fertility, affects about 25 per cent of female carriers.

This matters for staff because an older adult with a tremor or unsteadiness and a family history of learning disability may benefit from a referral to a neurologist or genetics service. Our guides on ataxia and tremor explain how to support people with these symptoms in the meantime.

Practical support for care staff

• Use the person's communication passport. Learn how the person communicates and what they find hard.
• Plan for anxiety and sensory sensitivity. Busy, loud or unpredictable settings can be stressful, so build in quiet time and advance warning of changes.
• Use visual supports and routines. These help with understanding and reduce distress.
• Make reasonable adjustments to healthcare. People with learning disabilities benefit from annual health checks and clear information. Be alert to joint problems and hypermobility.
• Review medicines carefully. Psychotropic medicines should not be used to manage behaviour without a clear clinical reason and regular review.
• Support families. Parents and siblings may be carriers and may have their own health concerns.

When to get help

If you notice a new or worsening tremor, balance problems, memory changes or other changes in a person's health, tell their GP. Families with questions about inheritance can ask their GP for a referral to NHS genetic services. In an emergency, call 999.

Frequently asked questions

Is fragile X syndrome the same as autism?

No. The source reports that many people with fragile X syndrome are autistic, but many are not, and autism can have other causes.

Do females have fragile X syndrome?

Yes. The source says about half of females with the full mutation have a mild to moderate learning disability, and it varies widely.

What is a premutation?

It is a smaller expansion of the gene, which does not cause fragile X syndrome but can lead to conditions such as FXTAS and FXPOI.

Where can staff build their knowledge?

The health and social care learning available through Learnsignal CPD can help you support people with learning disabilities.

This article is general information for care staff, based on NHS Genomics Education Programme information, and does not replace the advice of a person's own clinicians. If you are worried about someone's health right now, contact their GP, NHS 111 or, in an emergency, call 999.