DDX3X Foundation
Cycle 1
DDX3X Syndrome is a rare disease caused by a spontaneous mutation within a DDX3X gene at conception or can be inherited. The syndrome primarily affects girls due to its location on the X-chromosome, though there are some boys it has affected as well. DDX3X Syndrome is linked to intellectual disabilities, seizures, autism, low muscle tone, abnormalities of the brain, and slower physical developments.
Last updated 04/30/2026
Clinical
Disease Class
Intellectual disability and developmental syndromes
Body Systems
Endocrine
Nervous / Sensory
Organs
Brain
Ears
Esophagus
Eyes
Gallbladder
Heart
Intestines
Liver
Lungs
Mouth / teeth
Nose
Pancreas
Stomach
Throat/pharynx
Known Genetic Link
Yes, one or more genes directly cause the condition
Causative Genes
DDX3X
Contributory Genes
None specified / unknown
Type of Inheritance
De novo
X-linked dominant
X-linked recessive
Newborn Screening
No
Disease Mechanism(s)
Unknown
Age of Onset
Prebirth
Average Age at Diagnosis
Early childhood (age 1+-5)
Life Expectancy
Adulthood (age 18-64)
Elderly (age 65+)
Affected Sex(es)
Female
Male
National Prevalence
1001-10000
Global Prevalence
1001-10000
National Incidence
Unknown
Global Incidence
Unknown
Symptoms / Phenotypes
abnormal brain features
developmental delay
hypotonia
intellectual disability
livedo reticularis
microcephaly
movement disorders / ataxia / tremor
seizures / epilepsy
speech problems / apraxia
Biomarkers
Diagnostic
· Presence of mutation in the DDX3X gene detected through WES
Existing Therapies
None
Therapies in Development
Gene therapy
Repurposed drug
Therapeutic Development Stages
In preclinical development
In research/exploratory phase
Therapeutic Development Role
Access to registry or natural history study
Data analysis
Data sharing
Focus group participation or coordination
Funding
Outcome measures development
Recruitment and outreach to patients
Recruitment and outreach to trial sites / physicians
Results dissemination (including publications)
Sample provision
Study material design and/or review (not protocol) — includes patient-facing materials such as informed consent
Study protocol design and/or review (includes selection of outcome measures)
Travel coordination
Organizational & Research
Cell Lines
iPSCs
Cell Lines, Institution
University of California San Francisco (UCSF)
Cell Lines, Involvement
Funded
Cell Lines, share
Unsure
Disease Model
Mouse
Zebrafish
Disease Model, Involvement
Consulted
Funded
Own
Disease Model, share
Some of our disease models are freely available
Organizational Challenges
Not applicable
Clinical Trial Role
Not involved
Biobank, Institution
Coriell Institute
Biobank, Involvement
Consulted
Center of Excellence, Institution
Children’s Hospital of Philadelphia (CHOP)
Rush University
University of California San Francisco (UCSF)
University of Pennsylvania (PENN)
Center of Excellence, Involvement
Designed
Endorsed/Certified/Accredited
Funded
Registry
Yes, we have a registry that we created
Data Collected, Registry
Clinical data
Electronic health records/electronic medical records
Genetic data
Imaging data
Longitudinal natural history data
Medication usage
Patient contact info
Patient-reported data
Data Entered by, Registry
Both
Platform, Registry
Ordinal Data
Natural History Study
Yes, we have a natural history study that we created
Data Collected, Natural History Study
Electronic health records/electronic medical records
Genetic data
Imaging data
Patient-reported outcomes
Prospective data
Retrospective data
Platform, Natural History Study
REDCap
FDA Patient Listening Session
No
FDA Patient-Focused Drug Development (PFDD) Program
No
ICD Codes
We are working on obtaining an ICD-10 code
Diagnostic Guidelines
Yes, we have guidance available on our website
Science Advisory Board Policies
Yes, willing to share SAB policies
Research Network Policies
Has CRN but no policies
Patient Priority Survey
Yes
Patient Priority Survey, share
Yes, will share
Research Roadmap
Yes we have a Research Roadmap, and will share policies
International Chapters
Asia
Europe
Oceania
South America
International Partners
Europe
Oceania
South America
Other International Research Initiatives
Asia
Europe
North America
Oceania
South America