Fragile X syndrome: causes, symptoms and treatment

Our genetic code contains the instructions necessary to shape and develop our organism. We inherit much of who we are from our ancestors, although whether or not some of these instructions are expressed will depend on the environment in which we live.

However, sometimes there are several genetic mutations that can cause a disorder to exist in those who carry them. This is the case with fragile X syndromeThe second most common cause of mental retardation is for genetic reasons.

    Fragile X syndrome: description and typical symptoms

    Fragile X syndrome or Martin-Bell syndrome is an X-linked recessive genetic disease. The symptoms produced by this syndrome can be seen in different areas.

    The most notable are those related to cognition and behavior, although they may present with other symptoms such as typical morphological alterations or even metabolic problems. It still affects both men and women, as a rule, it is much more common in the former, also showing more pronounced and severe symptoms.

    Cognitive and behavioral symptoms

    One of the most characteristic symptoms is the presence of an intellectual disability. In fact, along with Down syndrome, Fragile X syndrome is one of the most common genetic causes of mental retardation. This handicap can be very variable.

    In the case of women, we observe a level of intelligence usually observed on the borderline of intellectual disability, with a CI between 60 and 80. However, in men, the level of disability is usually much higher, With a CI typically between 35 and 45. In this case, we would face moderate disability, which would mean slower and delayed development in major stages such as speech, with difficulties in abstraction and speech. need for some level of supervision.

    Another common aspect is the presence of a high level of hyperactivity, Showing motor restlessness and impulsive behaviors. In some cases, they can even harm themselves. They also often have difficulty concentrating and maintaining their attention.

    They can also present typically autistic behaviors, Which can lead to the presence of serious difficulties in social interactions, phobia of contact with other people, mannerisms such as shaking hands and avoiding eye contact.

      typical morphology

      In terms of physical characteristics, one of the most common morphological characteristics in people with fragile X syndrome is that they have a certain level of macrocephaly from birth, Possessing relatively large and elongated heads. Other common features are the presence of large eyebrows and ears, jawline and prominent forehead.

      It is relatively common to have hyperlax joints, especially in the limbs, as well as hypotonia or muscle tone below expectations. Deviations of the spine are also common. In men, macroorchidism, or excessive testicular development, can also appear, especially after adolescence.

      medical complications

      Regardless of the types of characteristics we have observed, people with Fragile X syndrome may have disorders such as gastrointestinal problems or less visual acuity. Unfortunately, many of them suffer from heart problems and are more likely to suffer from heart murmurs. A high percentage, between 5 and 25%, also suffers from local or epileptic seizures, whether localized or generalized.

      However, those with Martin-Bell syndrome they can have a good quality of life, Especially if the diagnosis is made early and there is treatment and education to limit the effects of the syndrome.

      Causes of this disorder

      As we have stated, Fragile X Syndrome is a disorder of genetic origin linked to the X sex chromosome.

      In people with this syndrome, the X sex chromosome suffers from a type of mutation which causes a specific series of nucleotides to appear in the FMR1 gene, specifically the Cytosine-Guanine-Guanine (CGG) chain, to appear excessively repeated throughout the gene.

      While subjects without this mutation may have 45-55 repeats of this chain, a subject with fragile X syndrome may have 200-1300. This prevents the gene from being able to express itself properly, so it does not produce the gene. FMRP protein when silenced. .

      The fact that the X chromosome is affected by the mutation is the main reason why the disorder is seen more often and with greater severity in men, by having only one copy of this chromosome. In women, by having two copies of the X chromosome, the effects are minor and may not even show symptoms (although they can be passed on to the offspring).

      Treatment of Martin-Bell syndrome

      Fragile X syndrome he currently has no type of care. However, they can treat the symptoms caused by this disorder in a palliative way and with the aim of improving their quality of life, thanks to a multidisciplinary approach integrating medical, psychological and educational aspects.

      Some of the treatments used with people with this syndrome to improve their quality of life these are speech therapy and various language therapies to improve their communication skills, as well as occupational therapy which helps them integrate information from different sensory modalities.

      Cognitive-behavioral programs and treatments can be used to help them establish basic and more complex behaviors. In terms of education, they must have individualized plans which take into account their characteristics and difficulties.

      Pharmacologically, SSRIs, anticonvulsants and various anxiolytics are used to reduce symptoms of anxiety, depression, obsession, restlessness and seizures. Psychostimulants are also used occasionally in cases where there is a low level of activation, as well as atypical antipsychotics in cases where aggressive or self-harming behavior usually occurs.

      Bibliographical references:

      • Grau, C .; Fernández, M. & Costa, JM (2015) Fragile X chromosome syndrome: behavioral phenotype and learning difficulties. Zero Century, vol. 46 (4), n ° 256. University of Salamanca Publishing.

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