Overview
X-linked creatine transporter deficiency (also called creatine transporter defect, CTD, or CRTR deficiency) is a rare inherited condition that affects how the brain and body use creatine. Creatine is a natural substance that cells — especially brain cells — need to produce energy. In this condition, a faulty gene means the body cannot properly move creatine into cells, so the brain is starved of the energy it needs to develop and work normally. The condition mainly affects males, though some females who carry the gene change can also have symptoms, usually milder ones. The most common signs include intellectual disability (difficulty with learning and thinking), delayed speech and language development, behavioral problems such as hyperactivity or autism-like behaviors, and seizures. Some affected individuals also have low muscle tone (floppiness) and slow physical development. There is currently no cure for X-linked creatine transporter deficiency. Treatment focuses on managing symptoms — for example, anti-seizure medicines for epilepsy, speech therapy, occupational therapy, and educational support. Creatine supplements have been tried but unfortunately do not help because the transporter needed to get creatine into brain cells is not working. Research into new treatments, including gene therapy approaches, is ongoing.
Also known as:
Key symptoms:
Intellectual disability (difficulty with learning, reasoning, and daily tasks)Delayed speech and language developmentBehavioral problems such as hyperactivity, aggression, or autism-like behaviorsSeizures (epilepsy)Low muscle tone (floppy muscles, especially in infancy)Delayed motor milestones such as sitting, standing, or walking lateShort stature or slow physical growthAttention difficulties and impulsivityMild facial features that may look slightly different from family membersAnxiety or mood problemsFeeding difficulties in infancy
Clinical phenotype terms (26)— hover any for plain English
X-linked recessive
Carried on the X chromosome; typically affects males more than females
Infantile
Begins in infancy, roughly 1 month to 2 years old
FDA & Trial Timeline
4 eventsLeonardo Calò, MD — NA
Hospices Civils de Lyon — NA
Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD)
TESS Research Foundation — NA
Data sourced from FDA regulatory filings and ClinicalTrials.gov. Updated periodically.
Treatments
No FDA-approved treatments are currently listed for X-linked creatine transporter deficiency.
2 clinical trialsare actively recruiting — trials can provide access to cutting-edge therapies.
View clinical trials →Rare Disease Specialist
Rare Disease Specialist
Treatment Centers
8 centersBaylor College of Medicine Rare Disease Center ↗
Baylor College of Medicine
📍 Houston, TX
🏥 NORDStanford Medicine Rare Disease Center ↗
Stanford Medicine
📍 Stanford, CA
🔬 UDNNIH Clinical Center Undiagnosed Diseases Program ↗
National Institutes of Health
📍 Bethesda, MD
🔬 UDNUCLA UDN Clinical Site ↗
UCLA Health
📍 Los Angeles, CA
🔬 UDNBaylor College of Medicine UDN Clinical Site ↗
Baylor College of Medicine
📍 Houston, TX
🔬 UDNHarvard/MGH UDN Clinical Site ↗
Massachusetts General Hospital
📍 Boston, MA
🏥 NORDMayo Clinic Center for Individualized Medicine ↗
Mayo Clinic
📍 Rochester, MN
👤 Mayo Clinic Center for Individualized Medicine
🏥 NORDUCLA Rare Disease Day Program ↗
UCLA Health
📍 Los Angeles, CA
Travel Grants
No travel grants are currently matched to X-linked creatine transporter deficiency.
Community
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Start the conversation →Latest news about X-linked creatine transporter deficiency
1 articlesCaregiver Resources
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Social Security Disability
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Questions for your doctor
Bring these to your next appointment
- Q1.What genetic test results confirm this diagnosis, and what does the specific SLC6A8 change mean for my child's outlook?,Should other family members, especially female relatives, be tested for carrier status?,What therapies are most important to start right away, and how often should my child receive them?,Are there any clinical trials or research studies we could consider joining?,What is the best plan for managing seizures, and when should I call emergency services?,Are there any dietary supplements or experimental treatments that might help?,What support services and educational resources are available for my child and our family?
Common questions about X-linked creatine transporter deficiency
What is X-linked creatine transporter deficiency?
X-linked creatine transporter deficiency (also called creatine transporter defect, CTD, or CRTR deficiency) is a rare inherited condition that affects how the brain and body use creatine. Creatine is a natural substance that cells — especially brain cells — need to produce energy. In this condition, a faulty gene means the body cannot properly move creatine into cells, so the brain is starved of the energy it needs to develop and work normally. The condition mainly affects males, though some females who carry the gene change can also have symptoms, usually milder ones. The most common signs i
How is X-linked creatine transporter deficiency inherited?
X-linked creatine transporter deficiency follows a x-linked recessive inheritance pattern. Genetic counseling can help families understand recurrence risk and testing options.
At what age does X-linked creatine transporter deficiency typically begin?
Typical onset of X-linked creatine transporter deficiency is infantile. Age of onset can vary across affected individuals.
Are there clinical trials for X-linked creatine transporter deficiency?
Yes — 2 recruiting clinical trials are currently listed for X-linked creatine transporter deficiency on UniteRare. See the clinical trials section on this page for phase, sponsor, and site details sourced from ClinicalTrials.gov.
Which specialists treat X-linked creatine transporter deficiency?
7 specialists and care centers treating X-linked creatine transporter deficiency are listed on UniteRare, sourced from ClinicalTrials.gov principal investigators, published research, and the NPPES NPI registry.