FXS Symptoms & Therapy

People with Fragile X do not all have the same symptoms, but they do have some things in common.

Intelligence and Learning:

  • Problems can range from the mild, such as learning disorders, to the severe, such as an intellectual or developmental disability.
  • FXS may affect the ability to think, reason, and learn.
  • Because many people with Fragile X also have attention disorders, hyperactivity, anxiety, and language-processing problems, a person with Fragile X may have more capabilities than his or her IQ score suggests.


As children with Fragile X begin to develop, they may grow into certain features that are typical of the syndrome including:

  • narrow face;
  • large head;
  • large ears;
  • flexible joints;
  • flat feet; and
  • prominent forehead.

These physical signs become more obvious with age.

Behavioral, Social, and Emotional:

  • Afraid or anxious in new situations
  • Trouble making eye contact with other people
  • Trouble paying attention or be aggressive (boys especially),
  • Be shy around new people (girls especially)
  • Attention disorders
  • Problems with hyperactivity

Speech and language:

Most boys with FXS have problems with speech and language including:

  • trouble speaking clearly;
  • stuttering, or leaving out parts of words; and  
  • problems understanding social cues, tone of voice, or specific types               of body language.

Girls do not usually have severe problems with speech or language.

Most children with FXS begin talking later, however a few might stay nonverbal throughout their lives.


Many children with FXS can be bothered by:

  • bright light,
  • loud noises,
  • certain ways clothing feels on their body.
  • These sensory issues might cause them to act out.

Symptoms are often milder in females than in males.