Fragile X syndrome

Fragile X syndrome is a genetic disease and is linked, as its name suggests, to a mutation on the X chromosome. It affects boys and girls, but is more serious and common in boys. Girls may be affected by the syndrome or simply carry the mutation with little or no symptoms. It is the first cause of hereditary mental deficiency.

Cause

The abnormality on the X chromosome causes a protein to be abnormally synthesized. The amount of synthesized protein (the expression of the gene) determines a lesser or greater range of symptoms. This protein is very important in the early stages of development and continues to be synthesized throughout life. It also determines the functions of other genes, hence the wide range of symptoms that the syndrome presents.

Symptoms

Fragile X syndrome can give a very wide range of symptoms, not everyone affected has all the symptoms. There are substantial differences between boys and girls.

Symptoms that may appear in children:

• Elongated face, large spread ears, and joint hyperelasticity
• Macroorchidism (large testicles): this trait manifests itself in adolescence
• Squint
• heart murmur
• Flat feet
• Epilepsy (not in all children)
• Mental retardation
• Delayed acquisitions and psychomotor
• Emotional and behavioral disorders
• Delay in language acquisition
• Hyperactivity or attention deficit
• Autistic behavior

Symptoms that may appear in girls:

• Facial features less marked than in children
• Mental retardation

Children affected by this syndrome have some strengths such as:

• They are very sociable and enjoy the company of others
• They are very receptive to cooperative work
• They have a sense of humor
• Good imitation ability
• Good visual and long-term memory; have a good sense of direction

Diagnosis

Diagnosis is made through a genetic and DNA study and can diagnose boys with the syndrome as girls who are carriers of the mutation. It can also be detected prenatally, during pregnancy. Early diagnosis is very important in order to offer the child the best possible medical and educational care.

Treatment

There is currently no treatment for Fragile X syndrome but gene therapy could provide a treatment option for these children in the future. The current treatment is based on alleviating the symptoms. Medical and educational follow-up is essential.