DDX3X
The information for this summary of DDX3X-related syndrome comes from research publications. This is not meant to take the place of medical advice.
Click here for our full DDX3X Gene Guide
The online Gene Guide includes more information about DDX3X such as the chance of having another child with this condition, behavior and development concerns linked to DDX3X-related syndrome or specialists to consider for people with this condition. Share this resource with family members or your clinical providers.
DDX3X-related syndrome is also called intellectual developmental disorder, X-linked syndromic, Snijders Blok type, or DDX3X neurodevelopmental disorder. For this webpage, we will be using the name DDX3X-related syndrome to encompass the wide range of variants observed in the people identified.
What is DDX3X-related syndrome?
DDX3X-related syndrome happens when there are changes in the DDX3X gene. These changes can keep the gene from working as it should.
Key Role
DDX3X plays a key role in the growth of the brain.
Symptoms
Because the DDX3X gene is important for brain activity, many people who have DDX3X-related syndrome have:
- Developmental delay
- Intellectual disability
- Changes in muscle tone
- Movement disorders
- Vision impairments
- Autism
- Attention-deficit/hyperactivity disorder (ADHD)
- Language impairment
- Heart defects
- Brain changes seen on magnetic resonance imaging (MRI)
How many people have DDX3X-related syndrome?
As of 2025, over 230 people with DDX3X-related syndrome have been described in medical research.
Support Resources
- Simons Searchlight Community – DDX3X Facebook group
- DDX3X Foundation Website – DDX3X.org
– Gene DDX3X – Facebook group - Unique – DDX3X Guidebook
- Geisinger Developmental Brain Disorder Gene Database – DDX3X
GeneReviews
GeneReviews are a great resource to bring to your child’s clinicians. These publications provide a summary of current research on genetic conditions and information on ongoing care.
Check out the GeneReviews for DDX3X.
Research Article Summaries
Below, we have summarized research articles about changes in the DDX3X gene. We hope you find this information helpful.
The information available about DDX3X is limited, and families and doctors share a critical need for more information. As we learn more from children who have a change in this gene, we expect this list of resources and information to grow.
Full versions of published research articles can be found on PubMed. PubMed is a National Institutes of Health (NIH) online database that is free. It has a collection of both medical and scientific research articles. A PubMed search for DDX3X articles can be found here.
You can also visit the Simons Foundation’s SFARI Gene website to see information for researchers about this gene.
Mutations in DDX3X are a common cause of unexplained intellectual disability with gender-specific effects on Wnt signaling
Original research article by L. Snijders Blok et al. (2015).
Read the abstract here and the Simons Searchlight summary here.
Research Opportunities
Simons Searchlight
Help the Simons Searchlight team learn more about DDX3X genetic changes by taking part in our research. You can learn more about the project and sign up here.
Research into speech & language skills in individuals with DDX3X variants: an international study
Researchers are running a project looking at speech & language in individuals with DDX3X variants. By improving our understanding of speech & language abilities, they hope to improve prognoses, better identify individuals in need of speech therapy, and develop more targeted therapies. *This study is not affiliated with Simons Searchlight. See their flyer here.
External Research Opportunity: FaceMatch
FaceMatch is a platform that helps parents and doctors contribute to an international secure image database of both undiagnosed and diagnosed children across the globe. *This study is not affiliated with Simons Searchlight. Learn more about FaceMatch.
If interested or would like to know more contact; angela.morgan@mcri.edu.au, or geneticsofspeech@mcri.edu.au.