What is Fragile X Syndrome?
Fragile X syndrome (FXS) is the most common known cause of intellectual disability, also known as mental retardation, and developmental disability that can be inherited (passed from one generation to the next). The exact number of people who have FXS is unknown, but it is estimated that about 1 in 4000 males and 1 in 6000 to 8000 females have the disorder. Although FXS occurs in both males and females, females generally have milder symptoms. Signs that a child has FXS include not sitting, walking, or talking as early as other children. This is known as having developmental delays. Often, there are other physical and behavioral signs, but features of FXS vary and signs can be subtle and easy to miss. Children often have a typical facial appearance that gets more noticeable with age. These features include a large head, long face, and prominent ears, chin, and forehead. Children who have FXS might also have learning disabilities, speech and language delays, and behavioral problems such a
