Fragile X syndrome, diagnosis and intervention

Fragile X Syndrome (FXS) is considered the second most frequent cause of intellectual disability, only behind Down Syndrome and is the first cause of hereditary disability. It is a syndrome whose transmission is linked to the X chromosome, which is why a higher incidence and degree of involvement is observed in men . Its estimated prevalence in the Spanish population is 1 / 2500-4000 in men and 1 / 4000-8000 in women. These figures are highly variable because, as we will explain below, Fragile X Syndrome is often not diagnosed.

It was first described in 1943 from the observation of a group of adult men with characteristic symptoms, although it was not until 1991 that the genetic alteration that causes it was discovered. This is the anomalous expansion of a triplet of the FMR1 gene, which is found on the X chromosome. The variability in the number of repeats of the triplet, beyond the 55 copies in which the range considered normal is situated, is very wide. A distinction is made between premutation (between 55 and 200 repeats) and complete mutation (more than 200). As a consequence of the mutation, the gene is inactivated and cannot perform the function of synthesizing the FMRP protein, which is responsible for regulating and providing stability to a series of cellular , transport and translation processes of other proteins.

PEOPLE WITH FRAGILE X SYNDROME

This mutation causes people with Fragile X Syndrome to have a characteristic physical appearance, although not too striking. Males may have characteristic facial features such as a long face, a broad forehead, large, set ears, and a prominent chin . These traits appear especially from adolescence, so it will be difficult to detect them and use them as a diagnostic clue in cases of young children. In the case of women this appearance is even less obvious.

The most characteristic of Fragile X Syndrome, as we say, is intellectual disability . Men are always more affected than women and levels of disability can range from mild or moderate to severe . It is likely that in the case of women this level of mild intellectual disability is not even diagnosed and, therefore, that the syndrome itself is not diagnosed.

However, the biggest problem with the diagnosis is the widespread ignorance that exists about Fragile X Syndrome which, added to a series of common characteristics that it usually shares with other genetic disorders or syndromes, means that the Syndrome is often not diagnosed. Fragile X or misdiagnosis .

HOW IS FRAGILE X SYNDROME DIAGNOSED?

Children with Fragile X Syndrome often have certain personality and behavioral traits reminiscent of Autism Spectrum Disorder : social relationship difficulties, stereotyped movements, restricted interests, etc. These characteristics do not always manifest themselves but, when they do, it is frequent that these children are directly diagnosed with Autism Spectrum Disorder , because they can meet all the diagnostic criteria.

The problem is that there are another series of differential characteristics in children with Fragile X Syndrome that mean that the intervention must be approached differently from the cases of Autism Spectrum Disorder. For example, children with Fragile X Syndrome usually develop language late, around 3 or 5 years , but this level of language eventually normalizes over time. On the other hand, what must be intervened and prioritized from the first moment is their intellectual disability, through cognitive stimulation from an early age. Between 20% and 30% of children with Fragile X Syndrome meet the clinical diagnostic criteria for Autism Spectrum Disorder, but it is estimated that between 2% and 6% of children diagnosed with autism would present the Fragile X Syndrome mutation.

To reach the diagnosis of Fragile X Syndrome it is essential to carry out genetic tests and the difficulty that may exist in accessing them often makes the diagnosis difficult. For this reason, the prevalence of the syndrome is estimated to be still much higher than is currently believed.

It can also be confused with ADHD , as children with Fragile X Syndrome often also have impulsive traits and attention problems. Once again, it is on intellectual disability that we have to focus, to know how to differentiate one and the other and recommend the diagnosis through genetic tests.

INTERVENTION IN PEOPLE WITH FRAGILE X SYNDROME

Because the discovery of Fragile X Syndrome is relatively recent , there are few studies with adults that can determine the evolution and prognosis of development of these people. Most of the studies are done with young children and the research with girls is also scarce.

However, it has been shown that early intervention improves the evolution and development of children with Fragile X Syndrome. Early Care professionals will work in a multidisciplinary way to, first of all, establish the child’s developmental profile. This way you will be able to determine which are your strong points and which are your weak points to act accordingly. Professionals, psychologists, speech therapists, psychomotricists , etc., will work in a coordinated way to intervene in the most appropriate way with the little ones and guide the family, giving them the necessary guidelines and guiding them in the future schooling of the little ones.