What is Fragile X Syndrome?

Fragile X syndrome is a birth defect occurring in about 2 of every 10,000 live births. It is more common in males, occurring in about 1 out of 3,600 and in about 1 of every 4,000-6,000 females. Fragile X syndrome can cause slow growth, mental retardation and other developmental delays. It accounts for about 2-3 percent of undiagnosed mental impairment.

Fragile X syndrome is caused by a mutation on the X chromosome. This mutation causes the Fragile X Mental Retardation-1 gene (FMR-1) to stop producing the FMR-1 protein, thus causing the syndrome. Because females have two X chromosomes, one of the chromosomes may have a "good" copy of the FMR-1 gene and this tends to lessen the effects of the FMR-1 gene shutdown on the other X chromosome. Males, on the other hand, usually have the more severe manifestation of the syndrome, since they do not have an extra X chromosome to compensate.

The results of the Fragile X syndrome may be most noticeable in developmental delays, although some physical characteristics may be present as well. Males in particular may have longer faces and ears, hyper flexible joints and other problems with connective tissue. They also often exhibit behavioral problems, and indeed, autism is a common manifestation of Fragile X syndrome in males. Females may also have behavioral problems, but generally to a lesser degree.

Fragile X syndrome is often diagnosed in early childhood if developmental delays are pronounced, but mild cases may not be diagnosed until adulthood, if at all. A DNA test is available and is 99 percent accurate for the syndrome.

There is no cure for Fragile X syndrome. Treatment of Fragile X syndrome consists largely of treating the symptoms. The child receives therapy for behavioral problems, physical therapy if needed, special education assistance and other assistance as needed. Most patients will need a treatment team of doctors and therapists, working together to help the person achieve as much as possible. For persons with severe Fragile X Syndrome, parents will need to consider advance life planning for the time when they are no longer able to care for their child. A social worker and attorney may be part of the treatment and life planning team, to make financial and living arrangements for the person.

With early intervention, Fragile X Syndrome patients are often able to live happy, productive lives, in spite of their physical and mental challenges.