This article describes the symptoms of fragile X syndrome, including behavioral symptoms and possible changes in physical appearance.
It explains what causes fragile X syndrome and how this condition is diagnosed and treated.
It also covers inheritance, related conditions, and screening.
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Not everyone with fragile X syndrome will experience all these potential issues.
The problems present and their severity also may change over an individuals lifetime.
Brain and Nervous System
Developmental delay and intellectual disability are major issues in fragile X syndrome.
For example, a child might first learn to talk or walk at a much later age than normal.
Some people with fragile X syndrome have normal intellectual functioning.
At the other extreme, some people have severe intellectual disability.
Behavioral issues are another big category.
It accounts for about 23% of all cases of autism.
Because of a genetic error, the FMR1 gene cant make FMRP the way it normally would.
This specific mutation is called a CGG repeat.
FMRP is an important protein, especially in the brain.
It plays key roles in regulating the production of other proteins in brain cells.
More Genetics
The FMR1 gene is found on the Xchromosome.
Thats the sex chromosome, of which females have two copies and males have one copy.
In males with fragile X syndrome, only one FRMP gene is available.
Thats why they tend to have fewer and less severe symptoms.
Another factor complicates the understanding of fragile X syndrome.
Some people have what is called a premutation of the FMR1 gene.
This is not a full-blown mutation causing fragile X syndrome, but it isnt quite normal.
People who have between 55 and 200 CGG repeats in the FMR1 gene have such a premutation.
Thats because intellectual disability and developmental delay can be triggered by many different sorts of problems.
However, other family problems might also point toward fragile X syndrome as a possibility.
A relative with early menopause or fertility issues might be another clue.
Its key that your physician gets a clear idea of all the problems involved.
This is critical, since not everyone with fragile X syndrome has identical symptoms.
Sometimes these medical problems can provide clues about the underlying cause of the problem.
Other times, subtle physical differences can give a clue about the presence of fragile X syndrome.
A variety of tests are sometimes used to help narrow in on a diagnosis.
These will depend on the specific symptoms present.
Such tests can sometimes rule out other possible causes.
For example, a child might receive tests like the following:
Genetic testingis essential for definitive diagnosis.
In some cases, even more specialized genetic tests may be necessary to pick up the diagnosis.
Its important that caregivers of a child provide insights about developmental and behavioral issues.
Its also essential to look for symptoms that might indicate autism.
Often, specialists can aid in these assessments.
Working with people who have specialized training in childhood genetic diseases like fragile X syndrome can be extremely beneficial.
Treatment of fragile X syndrome requires work from a variety of specialists.
This is written up in something called an individualized education plan (IEP).
Sometimes, medications are helpful for some of the problems of fragile X syndrome.
Additionally, its helpful to web link with other families.
The same gene involved in fragile X syndrome can cause associated disorders.
Genetic screening can be used to identified people who are affected.
Inheritance
Thegenetic inheritanceof fragile X syndrome is quite complicated and unusual.
Fragile X syndrome follows most of the patterns of what is called an X-linked dominant disorder.
Fragile X-Related Conditions
Something else complicates the inheritance of fragile X syndromepremutations.
People with premutations dont have fragile X syndrome, and they may not have any medical problems at all.
However, people with premutations are at risk of having certain other medical problems.
Females with premutations are at risk of another medical condition called fragile-X associated primary ovarian insufficiency (FXPOI).
This can causepremature menopauseor early ovarian failure.
Its important to get tested to understand your own medical risks as well as those of any potential offspring.
Prenatal diagnosis may be possible for people known to be carriers of the FMR1 gene mutation.
Summary
Fragile X syndrome is a genetic condition resulting in mutations on the X chromosome.
It can cause several symptoms, including developmental problems, behavioral symptoms, and changes in physical appearance.
Talk to a healthcare provider if you suspect fragile X syndrome in a child or yourself.
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