Brain Sci. 2020

Authors: Jessica Klusek, Jinkuk Hong, Audra Sterling, Elizabeth Berry-Kravis, and Marsha Mailick

At the time of this writing, three Fragile X specialty clinics are collecting supplemental information for FORWARD. They assess and collect longitudinal (over time) data on a group of tests to measure cognitive and behavioral function in the FXS population so that we can specifically understand the course of development in FXS. This is one of the two publications that was a result of those efforts.


Restricted and repetitive behaviors (RRBs) are a group of behaviors that include repetitive movements, inflexible adherence to routines, ritualistic behavior, restricted interests, and unusual sensory interests. RRBs are a known domain of ASD but also affect individuals with other neurodevelopmental disorders such as FXS. This study took at a look at what RRBs looked like in 154 individuals with FXS, 2–50 years old. Researchers examined the effect that age, ASD diagnosis, and IQ score had on RRB severity.

Unique RRB profiles emerging based on age and gender with increased severity of RRBs based on ASD diagnosis. Findings suggest a peak in RRBs between the ages of 7 and 12, the exception being sensory-motor behaviors, which appear to peak between the ages of 2 and 12 years old. An added diagnosis of ASD significantly increased repetitive behaviors in these individuals. IQ score alone did not seem to influence the presence of RRBs.

Why This Is Important

These findings contribute to specialists understanding of RRBs in FXS. Taking an individual’s diagnoses and sex into account may help clinicians assess and understand their restricted repetitive behaviors to form a treatment plan.

What Are the Next Steps

More research is needed to develop a deeper understanding of the effect IQ, gender, and ASD diagnosis have on the RRB profile of individuals with FXS and inform treatment. Looking at these behaviors over time may help professionals understand changes in RRBs in individuals with FXS over time.

more research results