How much do you know about fragile X syndrome?

Fragile X syndrome is an inherited disease that causes intellectual and developmental disabilities. This disease is passed from parents to children through genes. Fragile X syndrome is the most common inherited source of mental retardation in boys. People with fragile X syndrome usually experience a wide range of developmental and learning problems. This disease is a lifelong disease.

Fragile X syndrome is one of the most common hereditary causes of mental disorders. Fragile X syndrome occurs when a change or mutation occurs in a single gene[FragileXmentalretardationgeneFMR-1.

This syndrome affects approximately 1 person out of 3600 men and 1 person out of 4000 to 6000 women.

This FMR-1 gene normally produces a protein that may lead to fragile X syndrome.

Fragile X syndrome is a hereditary disease, which means that it can be transmitted from parents to children. Parents can have children with syndrome X have a fracture, even if the parents themselves do not have this syndrome. When this gene is transferred from parents to children, more severe changes occur in the gene.

Some people may have only minor changes in the FMR-1 gene, which is called a premutation, and may not show any of the symptoms of Fragile X syndrome.

Other people may have more changes in the FMR-1 gene, which is called complete mutation, which leads to the symptoms of fragile X syndrome.

Symptoms and signs of syndrome X What is a breaker?

None of the people with fragile X syndrome show the same symptoms, but there are some general symptoms in all people, the symptoms of most girls are milder than boys.

Intelligence and learning

Many people with fragile X syndrome have intellectual and learning disabilities. These problems can vary from mild learning disorders to severe retardation.


Adolescents and adults with X syndrome have large ears, a long face with a prominent chin, problems related to this syndrome include ear infections, flat feet, excessive flexibility and laxity of joints, and various bone problems.


Most children with Fragile X syndrome have behavioral problems. These people may be afraid or anxious about the new situation. Many children, especially boys, have problems concentrating and paying attention, and may even be aggressive. Girls may feel embarrassed and shy in communicating with new people.

Language and speech

Most boys with Fragile X syndrome have many problems related to speaking. They may often have problems in speaking clearly or have stuttering or even leave part of the words while speaking. They also have comprehension problems when they talk to others, for example: disorders in understanding the speaker’s tone and tone, girls usually do not have acute problems in the field of speaking and speech.


Many affected children are stimulated by certain stimuli, such as: bright light, loud sound, or the way some objects are touched, some children do not like to be touched or even have trouble making direct eye contact with other people. They are a problem.

the reason

A change or mutation in the gene located on the X chromosome leads to fragile X syndrome. All humans have 46 chromosomes, two of which are sex chromosomes. Mutations in X chromosome DNA lead to this syndrome. The gene responsible for Fragile X syndrome is called FMR-1 Fragile x Mental Retardation. This gene is expressed in three ways, which can be different depending on the repetition frequency and the DNA pattern known as CGG repetition.

People who have less than 60 CGG repeats have normal genes. People with CGG repeats, 60-200, have pre-mutation (pre-mutation) and this means that these people carry this otherwise normal gene with them, which is an unstable mutation that may spread in the next generations and the background provide its update. People with CGG repeats above 200 have complete mutations that lead to fragile X syndrome. The complete mutation causes gene silencing or methylation (deactivation) of the FMR-1 region of the gene. Normally, the FMR-1 gene produces a special protein called FMRP, when the gene is turned off, the person cannot make FMRP, and the lack of this protein leads to Fragile X syndrome.


Currently, there is no treatment for this syndrome, however, special educational conditions, speech therapy, occupational therapy, and behavioral therapy will be useful for solving many behavioral symptoms and cognitive problems caused by fragile X syndrome. In addition to this, new medicinal findings can be useful to some extent to eliminate aggression, anxiety, hyperactivity and lack of concentration of these people.


During the years 1970-1980, the available test for the diagnosis of fragile X syndrome was genetic and chromosomal tests, although this test was helpful, but this test did not always show correct results.

The PCR analysis method can also be useful for determining the frequency of CGG repetitions in people with normal or pre-mutation genes, but this selective method is not used to detect complete mutations. But it determines the pre-mutation and frequency of repetition of CGG and normal gene with determination.


One of the prominent features of this state is that this gene can change over generations and reach its unstable form, and there is a greater possibility that this unstable gene will express itself more intensely in the next generations. Gene change in pre-mutation manifests itself in the next generation as full mutation. Premutation often does not show visible effects, however, premutation in older adults can manifest with neurological and parkinsonian symptoms.

Full mutation

Complete mutation means that the CGG repetition of the individual’s gene is more than 200 times on the DNA. In addition, most mutated genes have a degree of methylation that leads to gene silencing. A small percentage of men are fully mutated and do not have mental retardation. About 30% of women with complete mutation do not have cognitive problems. The rest of the women with complete mutation will have problems in cognitive, behavioral or social functions, and physical symptoms may be observed in women with a milder form.

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