Fragile X Syndrome: A-to-Z Guide from Diagnosis to Treatment to Prevention

lazy summer

Related concepts:

Martin-Bell syndrome, Marker X syndrome, Cluttering

Introduction to fragile X syndrome:

Fragile X syndrome is the most common cause of mental retardation in boys.

What is fragile X syndrome?

Fragile X syndrome is a condition caused by a fragile area on the X chromosome. This section of the chromosome contains ‘repeats’ in the genetic code. Higher numbers of repeats is associated with more severe forms of the disease.

Who gets fragile X syndrome?

The number of repeats in a fragile X chromosome tends to remain constant when transmitted by a father but to increase each time it is transmitted by a mother. Those with 200 to 2000 repeats (or even more) have the symptoms of full-blown fragile X syndrome. Girls with fragile X syndrome have varying degrees of symptoms.

What are the symptoms of fragile X syndrome?

The classic symptoms are mental retardation, large size, large testicles, and a long face with a prominent jaw and large ears. Often the eyes are pale blue.

Torticollis and cleft palate are more common in those with Fragile X.

These children also tend to be hyperactive and sometimes have some of the stereotypical movements associated with autism.

Cluttering is the name of their characteristic speech pattern. Like stuttering, cluttering is a speech disorder, but cluttering involves pauses in normal speech that are too short, too long, and in the wrong places. These may come from talking in fast spurts, or from not knowing what one wants to say. Corrections, revisions, and interjections are common. (People who stutter know what they want to say but have difficulty getting the words out.)

Is fragile X syndrome contagious?


How long does fragile X syndrome last?

This is a lifelong condition.

How is fragile X syndrome diagnosed?

Fragile X is diagnosed with specific chromosome testing.

How is fragile X syndrome treated?

There is no cure for fragile X syndrome. Therapy is aimed at helping people with fragile X reach their full potential.

How can fragile X syndrome be prevented?

Once a baby is conceived with fragile X, nothing can change that. Timing of childbearing may make some difference in inheritance. We do know that women who are carriers are more likely to have had older fathers.

Related A-to-Z Information:

Attention Deficit Hyperactivity Disorder (ADHD), Cleft Lip and Palate, Down Syndrome, Fetal Alcohol Syndrome, Head Banging Phenylketonuria, Stuttering, Tantrums, Torticollis

Reviewed by: Khanh-Van Le-Bucklin, Rebecca Hicks
Last reviewed: November 10, 2009
Dr. Alan Greene

Article written by

Dr. Greene is the founder of (cited by the AMA as “the pioneer physician Web site”), a practicing pediatrician, father of four, & author of Raising Baby Green & Feeding Baby Green. He appears frequently in the media including such venues as the The New York Times, the TODAY Show, Good Morning America, & the Dr. Oz Show.