Fragile X syndrome is a genetic disease that occurs due to a mutation in the X chromosome, leading to the occurrence of several repetitions of the CGG sequence. Because they only have one X chromosome, boys are more affected by this syndrome, showing more characteristic signs, such as an elongated face, large, flapping ears, in addition to behavioral traits similar to that of autism. This mutation can also happen in girls, however the signs and symptoms are much milder, because as they have two X chromosomes, the normal chromosome compensates for the defect of the other.
The diagnosis of fragile X syndrome is difficult, as most symptoms are nonspecific, but if there is a family history, it is important to carry out genetic counseling to check the chances of the syndrome occurring. Understand what genetic counseling is and how it is done.
Signs and symptoms of fragile X syndrome
Fragile X syndrome is very characterized by behavioral disorders and intellectual impairment, especially in boys, with learning and speech difficulties. In addition, the characteristic symptoms of fragile X syndrome are:
- Elongated face; Large, protruding ears; Protruding chin; Low muscle tone; Impairment of connective tissue; Flat feet; High palate; Prolapse of the mitral valve; Single palmar fold; Strabismus or myopia; Scoliosis; Hand-biting habit; Recurrent otitis.
Most features related to the syndrome are only noticed from adolescence. In boys it is common in adolescence to have an enlarged testicle, while women may have problems with fertility and ovarian failure.
How the diagnosis is made
The diagnosis of fragile X syndrome can be made by molecular and chromosomal tests, to identify the mutation, the number of CGG sequences and the characteristics of the chromosome. These tests can be done with a blood sample, saliva, hair or amniotic fluid.
How the treatment is done
Treatment for Fragile X syndrome is done through behavioral therapy, physical therapy and, if necessary, surgery for physical changes.
People with a history of fragile X syndrome in the family should seek genetic counseling to find out the likelihood of having children with the disease. Men have the XY karyotype, and if they are affected they can transmit it only to their daughters, never to their sons since the gene received by boys is Y, and this does not show any alteration related to the disease.
