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In this Article

• What is Fragile X syndrome?
• What causes Fragile X syndrome?
• What keeps the FMR1 gene from producing FMRP in Fragile X syndrome?
• Patient Discussions: Fragile X Syndrome - Describe Your Experience
• Fragile X Syndrome Glossary
• Fragile X Syndrome Index

What are the signs and symptoms of Fragile X syndrome?

Not everyone with Fragile X has the same signs and symptoms, or to the same degree. Even affected children in the same family can have different signs and symptoms. These differences often make Fragile X hard to diagnose. However, because everyone with Fragile X has too little FMRP, they do share a pattern of certain physical, social, mental, and sensory characteristics. Although most of the Fragile X research to date has focused on children, adults with Fragile X also have most of these signs and symptoms.

In general, the signs and symptoms of Fragile X fall into five categories:

• Intelligence and learning
• Physical
• Social and emotional
• Speech and language
• Sensory
• Disorders commonly associated or sharing features with Fragile X

Now consider each category in more detail.

Intelligence and learning

Many people with Fragile X have impaired intellectual functioning, which affects their ability to think, reason, and learn. In most cases, researchers use an intelligence test to measure intellectual functioning, resulting in an IQ (intelligence quotient) score. But this score reflects many things besides the ability to think. Attention disorders, hyperactivity, anxiety, and language processing problems can interfere with test-taking skills and learning. Because many people with Fragile X have these problems, a person with Fragile X may have more capabilities than his or her IQ score suggests.

Researchers consider people who score between 85 and 115 on an IQ test to have "average" intelligence.⁷ On the whole, less than 20 percent of males with Fragile X have an IQ in this range.² At the same time, few people with Fragile X are severely or profoundly impaired, with IQs below 40 or 25, respectively.⁸ In general, those with a full mutation tend to have an IQ somewhere in between 40 and 85, which is considered mild to moderate mental impairment.

Females tend to be less seriously affected by Fragile X than males. Even among females who have full-mutation FMR1 genes, only about one-third have an IQ in the mental retardation range.⁶ Females with Fragile X are more likely to have relatively normal cognitive development, or they may show a learning disability where their academic achievement in some areas is lower than their overall ability to learn. For example, a female with a learning disability in math might score several grades below her grade level in math, even though her IQ is within the normal range.

Many factors influence intelligence, and, like most individuals, people with Fragile X have areas of both strength and weakness. For example, people with Fragile X tend to have good memories for pictures and visual patterns. This ability helps them to learn to recognize letters and words. They are also generally able to follow instructions that are presented as pictures. Their main weaknesses are in thinking about abstract ideas, organizing information, planning ahead, and solving problems.

No matter what their IQ or areas of intelligence, all children and adults with Fragile X are capable of learning. Most children will progress in school and develop basic academic skills. Many adults can learn to take care of themselves and work at a job. People with Fragile X may need more time to learn, special teaching methods, or a specially tailored environment (see the Suggestions for working with individuals with Fragile X box), but they usually can and do make steady progress.