Fragile X syndrome affects men and women differently. It causes mild and moderate intellectual disability in women and men respectively. They are found to have distinct physical features, such as bulging ears, prominent chin, large head, loose joints, and long face amongst others. However, these features may not appear in the early years. So parents usually find out about this condition when their children reach puberty. Delays in acquiring language and motor skills are not apparent at a younger age. They also become obvious over time. Fragile X patients also develop autistic behaviour amongst other behavioural abnormalities.
Fragile X syndrome is a result of an abnormality found in the FMR1 gene, which present in the X chromosome. FMRP, a type of protein produced by X chromosome helps in adequate cell function. This is why Fragile X syndrome is sometimes referred to as XXX chromosome disorder in many countries across the world. Also, Fragile X disorder is called so because some people who have this disorder appear to have their X chromosome fragile or broken. And now we know that the X chromosome in affected people is broken or fragile at the same location where FMR1 gene is present.
Causes of Fragile X Syndrome
The protein produced by the FMR1 gene facilitate communication between different nerve cells. This protein plays a very important role in the normal development of the brain children. The FMR protein is produced in very small amounts or not produced at all in children with Fragile X.
People suffering from this disorder are also found to have more than normal copies of CGG DNA segment. Normally, this segments is found from 5 to 40 times but Fragile X patients have it over 200 times. There is a direct relation between the available amounts of this segment with the severity of symptoms. More the quantity of CGG DNA, more severe the symptoms. A father can pass the FMR1 abnormality to daughters while mothers can pass it on to any of their children.
The likelihood of boys having Fragile X disorder is higher than that or girls. Symptoms in boys are also more severe. There are 2 copies of X chromosome in girls so their chances of having this condition is very low. Even if the FMR gene in one copy undergoes mutation, the other ones can work fine. On the other hand, boys have one copy of X and one copy of Y chromosome. So, a change in FMR gene in X chromosome will most likely result in Fragile X Syndrome in boys. Also, there are people who can inherit XXX chromosome disorder from their parent but won’t have any symptoms. They are simply carriers who can pass on the abnormal FMR gene to future generations.
Symptoms of Fragile X Disorder
Fragile X Syndrome causes varying degree of intellectual disability in men and women. Different men experience different physical changes, most of which may not be visible untill puberty. We have already discussed these physical changes. We are just going to add a few more, including ear infections, dental problems, flat feet, heart problems, arched palate, crossed eyes, and others. Symptoms that are not as common as others include hyperactivity, occasional seizures, and toe walking amongst others.
Fragile X Diagnosis
You can find out whether your baby who is yet to be born has Fragile X or not by getting these tests done during pregnancy:
Chorionic villus sampling or CVS
Cells present in the placenta are examined to find out if there is a change in the FMR1 gene.
The presence of FMR1 change is confirmed after examining amniotic fluid sample Once the baby is born, you can still find out if they have Fragile X,
How Is It Diagnosed?
These tests can be done during pregnancy to see if an unborn baby has fragile X:
Doctors check a sample of amniotic fluid for the FMR1 gene change
Chorionic villus sampling (CVS)
Doctors test a sample of cells from the placenta to check for the FMR1 gene
After the child is born, a blood test can diagnose fragile X syndrome. This test looks for the FMR1 gene change. Babies that are born with this syndrome rarely show signs in their early years. It is only after a few years that the signs start to become apparent.
Fragile X Treatment
There are several treatment modalities that can help individuals with Fragile X improve the quality of their lives. Some of these include behaviour modification programs, speech therapy, special education, occupational therapy, and others. A concerted effort that combines different modalities can go a long way in helping affected individuals make progress.
Fragile X Syndrome can be easily managed with the right treatment approach. Early diagnosis is the key.