Fragile X Syndrome & Autism

Families and some providers are often confused by the relationship between Fragile X syndrome and autism. It is important to note that it is more common for a child to be diagnosed with autism first and receive an additional diagnosis of FXS. There are overlaps and gaps between the two conditions, and understanding these distinctions can be particularly helpful when deciding on the most appropriate medical, therapeutic, and education interventions, and will increase the potential for both short- and long-term benefits.

Treatment Recommendations

The NFXF’s family-friendly Treatment Recommendations are in-depth documents developed by NFXF staff, members of the NFXF’s Fragile X Clinical & Research Consortium (FXCRC), and other Fragile X professionals, and reviewed and edited by the entire FXCRC.

Link to Understanding Autism Spectrum Disorder in Fragile X Syndrome treatment recommendations.

Fragile X Syndrome and autism can be confusing for families. This consensus helps explain how they can overlap and how to get the best treatment for them, plus advice from experts on how to help individuals with Fragile X Syndrome and autism.


From Our Blog

  • Two heads overlapping.

FXS and ASD: Similar But Different

By |Apr 2, 2018|

This discussion provides clinical perspectives on the behavioral differences between FXS and what are thought to be core features of autism. There is still much to be learned about identifying behaviors that suggest the presence or absence of ASD in FXS.

  • A clinician in a white lab coat kneeling on the floor next to a young boy wearing shorts sitting on the floor. She is engaging with the boy.

A Blood Test for Autism? Not So Fast

By |Feb 20, 2018|

Among families and professionals, in schools and therapeutic settings, there is already a great deal of confusion about the relationship between genetic test results and developmental diagnoses. We challenge the the notion that autism itself can be directly diagnosed through a blood test.

Additional Resources

Understanding Fragile X & Autism
Individuals with Fragile X syndrome (FXS) are frequently co-diagnosed with autism spectrum disorder, and families and some professionals are often confused by the relationship between the two. Much of our understanding has so far come from family surveys and small studies, but larger studies—including those utilizing data from the FORWARD Registry & Database — emerging to help us better understand the impact of an autism diagnosis in the care of people with Fragile X syndrome, and whether the link between the two extends beyond behavioral similarities.

Delineating Repetitive Behavior Profiles Across the Lifespan in Fragile X Syndrome
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.

ASD Diagnosis in Fragile X Syndrome
This research suggests there are differences between the diagnosis of FXS and FXS+ASD. More work needs to be done to examine additional modifications, beyond the deletion of non-informative items, that can further improve the diagnostic potential of the SCQ and SRS in FXS.

Behavioral Issues in FXS+ASD
While parents may be well aware of the differences between FXS, ASD, and FXS+ASD, teachers, clinicians, and other professionals, need to understand that FXS+ASD isn’t merely a sum of its parts.