Q99.2: Fragile X chromosome

You have fragile X syndrome.

Somatic cells usually hold a complete blueprint of your body. This blueprint consists of genetic information. The genetic information is encrypted in the chromosomes. In humans, somatic cells usually have 23 pairs of chromosome, so 46 chromosomes in all.

The X chromosome and the Y chromosome determine a person’s biological gender. Men normally have one X chromosome and one Y chromosome. Women normally have 2 X chromosomes.

With fragile X syndrome, part of the genetic information on the X chromosome is damaged. The damaged X chromosome is inherited. Other family members may therefore also have a damaged X chromosome. However, the other family members may nevertheless be healthy. Fragile X syndrome can vary in severity.

Because of the damaged genetic information, the cells cannot form a certain protein. This has various effects.

Fragile X syndrome can cause an elongated head and prominent ears. The muscles may be weaker and the joints very mobile. Epileptic seizures may occur. An epileptic seizure causes lots of nerve cells in the brain to be overactive at the same time. This causes certain muscles to cramp again and again, for example.

Fragile X syndrome can cause lower intelligence than the average. You may then be unable to learn and apply new things so quickly. It may also be more difficult to understand connections and adapt to new situations.

You may learn to speak later than other children. When speaking, the pronunciation can also be unclear. You typically also find arithmetic difficult.

Fragile X syndrome can also affect behavior. Sometimes it is difficult to concentrate or the person is very restless. You may also get angry easily. You may find it difficult to come into contact with other people. You may be shy or anxious, especially in unfamiliar situations. It is possible that you repeat the same movements or words again and again.