Mother with intellectual disabled child with drawing during consultation with psychotherapist
Fragile x syndrome is one of the most common genetic disorders that causes intellectual disability in children.

Understanding Fragile X Syndrome

Fragile X syndrome (FXS) triggers a wide array of development issues, including intellectual impairment, hyperactive behavior, learning disabilities, and autism.

Kids who are born with this disorder require special education and professional treatment to learn and grow like other children.

Additionally, medicines and other specialized therapies are often used to help alleviate physical symptoms and improve behavior in children affected with fragile X syndrome.

What Is Fragile X Syndrome?

FXS is one of the most common genetic disorders that can cause intellectual disability in children. It affects approximately 1 in 4,000 boys and 1 in 8,000 females.

Almost all cases of FXS are triggered by a mutation (change) in the FMR1 gene where a DNA fragment called the CGG triplet repeat is extended. The peculiarly extended CGG fragment deactivates the FMR1 gene, preventing it from generating a protein known as fragile X mental retardation protein. Absence of this protein causes FXS in both males and females.

What are the Common Symptoms of Fragile X Syndrome?

FXS can trigger development delays, learning disabilities, and behavioral difficulties. Disabilities differ with severity.

Fragile X Syndrome in Boys

Boys with FXS have some level of intellectual impairment. They have a unique facial appearance, epitomized by huge head size, protruding forehead and chin, a protracted face, and bulging ears. What’s more, males with FXS have loose joints and huge testes after puberty.

Boys with this inherited disorder may have serious behavioral issues like hyperactivity, anxiety, temper tantrums, hand biting, hand flapping, and autism.

Once they reach puberty, they may have poor eye contact, difficulties in distractibility and impulse control, and perseverative speech. They may also experience eye, skin, orthopedic, and heart problems.

Fragile X Syndrome in Girls

Girls with FXS have a mild mental disability. Family members with a smaller amount of FMR1 changes may not suffer from an intellectual impairment but may have other health issues. Women with fewer FMR1 changes may experience premature menopause or problems with getting pregnant.

Tremors and poor coordination are common in both males and females.

What are the Causes of Fragile X Syndrome?

The X chromosome features the FMR1 gene that synthesizes FMR protein, which aids nerve cells in communicating with one another. This protein is instrumental in the normal development of the brain.

Kids with FXS produce insufficient FMR protein or even lack it altogether. They also have more repetitions of CGG DNA segment than usual. Usually, this DNA fragment is repeated between five and 40 times. However, in individuals with FXS, it is repeated over 200 times. The higher the level of repetitions, the more severe the symptoms are.

The odds of a woman with the FMR1 gene mutation transferring it to any of her children is 50%. A man can only transfer this mutated gene to his daughters. The risks of getting fragile X is higher in boys than girls.

Moreover, the symptoms of this genetic condition are more severe in boys than in girls. Remember, girls have two X chromosome, and if one X chromosome carries the defective gene, the other will be okay. Boys, on the other hand, have a single X chromosome and a single Y chromosome. So if the mutative gene is on the X chromosome, they will experience signs and symptoms of FXS.

Some individuals get the fragile X gene but don’t show the symptoms – they are known as carriers. It’s important to keep in mind that while these individuals don’t exhibit symptoms of the condition, they can still transfer the defective gene onto their children.

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How Is Fragile X Syndrome Detected and Diagnosed?

There are limited outward symptoms of FXS in babies; however, a large head circumference is one indicative sign of the condition. A skilled geneticist may discover hidden differences in facial features.

Intellectual deficiency is the mark of this genetic disorder, and this could be the only sign of the condition in females.

Geneticists use a DNA blood test known as an FMR1 DNA test to diagnose fragile X syndrome. This test identifies alterations in the FMRI gene that are caused by FXS. Based on the results, the medical expert may decide to carry out extra testing to establish the severity of the disorder.

Doctors may recommend FXS test for kids who display symptoms of delays in development as well as other outward signs of FXS. Presence of a family history of FXS is another crucial reason for this test. Most Boys are diagnosed with FXS when they are between 35 and 37 months. Girls, on the other hand, are typically diagnosed around 41.6 months.

Fragile X Syndrome Treatment

There are no specific medications for fragile X. Treatment services can help affected children acquire important skills and improve behaviors. Here are options that can prove helpful in the management of FXS.

  • Special education to ease the learning process. There are educational plans like IEP and 504 that enable schools to offer the required support to children with FXS.
  • Professional therapy in speech and language.
  • Behavioral therapy.
  • Occupational therapy to assist with everyday tasks.
  • Medications to avert seizures, alleviate attention deficit disorder (ADD) symptoms such as hyperactivity, and manage other behavioral problems. Medications include methylphenidate (Ritalin), clonidine (Catapres), guanfacine (Intuniv), and SSRIs like sertraline, duloxetine, and paroxetine.

Life with Fragile X Syndrome

Although the lifespan of individuals with FXS is typically normal, there is limited data in the medical literature concerning adults with FXS. The impact of certain medical problems and related complications on people with FXS may differ since not all affected individuals have the same characteristics.

Affected males experience moderate to a serious mental disability, but one third to half of females with FXS have average intellectual ability. For this reason, some affected adult women may live extremely normal lives such as living independently, having friends, engaging in an array of leisure activities, pursuing higher education, and having a full-time job. However, affected adult males are at a heightened risk of having little to no independence.

Specific challenges that individuals with FXS face in their adulthood include the capability to dress, eat, and converse, collaborate with others, and the existence of mental health conditions like anxiety and depression.

Additionally, individuals with FXS together with an autism spectrum disorder may have far less independence in adult life compared to those with fragile X syndrome only.


Fragile X syndrome itself doesn’t worsen over time; however, the severity of its symptoms may vary at different points in the life of the affected individual. Behavioral symptoms may improve, worsen, or remain the same throughout a person’s life.

While FXS isn’t “curable” in the typical sense, special treatments and early interventions can help enhance function and prevent complications.