Signs & Symptoms
No one individual will have all the features of FXS, and some features, such as a long face and macroorchidism, are more common after puberty. Some of the features are due to poor connective tissue, such as flexible joints, flat feet, and high arched palate.
Physical features may include:
- Large ears
- Long face
- Soft skin
- Flexible joints — particularly fingers, wrists, elbows
- Low muscle tone
- Flat feet
- High arched palate
- Large testicles (called “macroorchidism”) in post-pubertal males
Behavioral characteristics may include:
- Sensory processing challenges (sensitive fabrics or clothing, loud noises, crowds, food textures, etc.)
- Hand-flapping, hand-biting
- Poor eye contact
- ADHD (attention deficit/hyperactive disorder)
- Autism spectrum disorders
- Increased risk for aggression
- Sleep disorders
- Cognitive abilities in FXS include a range from mild learning disabilities to more severe intellectual disabilities. The majority of males with Fragile X syndrome demonstrate moderate intellectual disability.
- Speech and language delay
- Motor delay (late crawling, walking, toileting)
Medical issues may include:
- Ear infections (also often due to poor connective tissue)
- Strabismus (crossed eyes)
Disposition characteristics often include:
- Very social and friendly
- Excellent imitation skills
- Strong visual and long-term memory
- Especially nice, likes to help others
- Wonderful sense of humor
Behavioral characteristics seen in males can also be seen in females, though females often have a milder presentation of the syndrome’s behavioral, physical, and connective tissue features.
About one-third of females with FXS have no to very mild learning disabilities, about a third have mild learning disabilities, and a third have moderate to significant intellectual disabilities.
Additional issues sometimes seen are:
- Emotional and mental health issues
- General anxiety
- Social anxiety
A small percentage of females who have the full mutation of the FMR1 gene that causes FXS will have no apparent signs of the condition — intellectual, behavioral, or physical. These females are often identified only after another family member has been diagnosed.