GPs urged to start testing for Fragile X syndrome

One in every 250 women and one in every 600 men have the gene

A charity is urging GPs to test patients for a genetic condition that is the most common inherited cause of learning disability. There is a “surprising lack of awareness” around Fragile X, experts said.

Fragile X syndrome is caused by an alteration to a gene on the X chromosome, which disrupts the production of a protein needed for brain development. About one in 250 women and one in 600 men are carriers of the abnormal gene that causes Fragile X syndrome, according to the Fragile X Society, with female carriers at a higher risk of early menopause.

Women with the gene have a 50% chance of passing on the condition to their children, while an affected man will pass the condition on to daughters, but not sons. Fragile X syndrome affects about one in 4,000 males and one in 6,000 females, causing a range of developmental issues.

Pete Richardson, managing director of the Fragile X Society, said: “As the most common inherited cause of learning disability, there is a surprising lack of awareness around Fragile X syndrome. Carriers of the Fragile X pre-mutation often won’t know they are affected.”

People are more likely to be carriers if they have a family history of Fragile X syndrome – or of intellectual disability, developmental delay or autism of unknown cause – as well as infertility problems associated with elevated follicle-stimulating hormone levels or premature ovarian failure.

Women with ovarian insufficiency also have a 2-15% chance of being a Fragile X carrier. Mr Richardson added: “When a woman shows signs of premature menopause, being a Fragile X carrier is often the last thing that doctors will investigate.

“We need this to change. Now.”

According to the Fragile X Society, patients who suspect they may carry the gene can ask medical professionals for a Fragile X (FMR1) DNA test. Alex McQuade, 41, raised concerns when her baby missed his developmental milestones.

She said: “At no point was there a conversation about genetics, despite myself and husband Chris telling doctors that I had a female cousin with what I thought was an autistic son.”

The couple, from Groby, Leicestershire, thought the issues experienced by their son, Evan, now 10, were a one-off. However, their second child Xander, now seven, had similar problems.

Mrs McQuade said: “I began doing my own research online. I knew it was like autism, but autism didn’t quite fit. It wasn’t long before I came across Fragile X syndrome. When I found the list of physical symptoms there was no doubt in my mind that the boys had it.”

What is Fragile X syndrome and how do you know if you carry it?

What is Fragile X syndrome?

“Fragile X Syndrome (FXS) is the most common inherited cause of learning disability,” says Richardson. “The condition affects approximately one in 4,000 males and one in 6,000 females.

“It can cause a wide range of difficulties with learning, as well as social, language, attentional, emotional and behavioural problems.”

There are also a number of misconceptions around this condition about family history and gender that Richardson wants to address.

“The mutation that causes FXS can grow larger when passed on to the next generation, so people with FXS may not have a family history,” clarifies Richardson. “Also, both girls and boys can have FXS. However, females often have a milder presentation of the syndrome’s features.”

What causes it?

“Fragile X syndrome is caused by a change in the FMR1 gene, and the FMR1 gene is located on the X chromosome,” explains Richardson. “This abnormal gene, which can be passed from generation to generation, is usually inherited through the gene that is carried by women.

“Although both males and females can be FMR1 carriers, and can pass the premutation on to their offspring.”

What are the symptoms?

Fragile X syndrome causes a wide range of physical, mental and behavioural symptoms, including mild to severe intellectual disability.

“ Common behavioural features include short attention span, distractibility, impulsiveness, restlessness, over activity and sensory problems,” notes Richardson. “Learning disabilities occur in almost all males with Fragile X, to differing degrees.”

However, some females with the condition can seem less affected.

“Because females have two X chromosomes, and usually only one of them is affected by Fragile X, the impact of the condition varies,” explains Richardson. “Some females appear unaffected, others have a mild learning disability, and some have a more severe learning disability.”

“Girls with or without learning disabilities may show concentration problems and social, emotional and communication difficulties related to extreme shyness and anxiety in social situations.”

There are some physical features associated with Fragile X, but these are often not very obvious in young children.

“Physical features include a long face, large or prominent ears, and flat feet – which usually become more noticeable in young adults than in children and in males more than females,” says Richardson. “Males with the condition may also have enlarged testes.”

Are carriers of Fragile X at risk of any health problems?

Women carriers often experience early menopause.

“Fragile X-Associated Primary Ovarian Insufficiency (FXPOI) is a condition that can affect carrier women under the age of 40,” highlights Richardson. “Symptoms include decreased or abnormal ovarian function, which can lead to infertility or fertility problems, irregular or absent periods, or premature ovarian failure.

“When a woman shows signs of premature menopause, being a Fragile X carrier is often the last thing that doctors will investigate. We need this to change.”

How is it diagnosed?

The only way you can tell if someone has the condition is through a DNA test.

“This process is easier if there is an identified carrier already in the family, or someone with Fragile X syndrome and can be arranged by a GP/family doctor, or any physician or genetic counsellor,” explains Richardson.

How is it managed/treated?

Richardson wants to emphasise that while there is no cure, some treatments can help minimise the symptoms of condition.

“Individuals with Fragile X who receive appropriate education, therapy services, and medications have the best chance of using all of their individual capabilities and skills,” says Richardson. “Even those with an intellectual or developmental disability can learn to master many self-help skills.”

Early intervention is also very important.

“Because a young child’s brain is still forming, early intervention gives children the best start possible and the greatest chance of developing a full range of skills,” explains Richardson. “The sooner a child with Fragile X syndrome gets treatment, the more opportunity there is for learning.”