X-linked creatine deficiency

Title

Other Names:

Mental retardation , X-linked with seizures, short stature and midface hypoplasia; Mental retardation , X-linked, with creatine transport deficiency; X-linked creatine transporter deficiency; Mental retardation , X-linked with seizures, short stature and midface hypoplasia; Mental retardation , X-linked, with creatine transport deficiency; X-linked creatine transporter deficiency; X-linked creatine deficiency syndrome; Creatine deficiency, X-linked See More

Categories:

Congenital and Genetic Diseases; Metabolic disorders; Nervous System Diseases; Congenital and Genetic Diseases; Metabolic disorders; Nervous System Diseases; Newborn Screening See More

Summary Summary

X-linked creatine deficiency is a rare condition that primarily affects the brain. Signs and symptoms generally develop before age 2 and may include mild to severe intellectual disability; delayed speech development, behavioral problems (i.e. autistic features, hyperactivity), and seizures. Less commonly, affected people may have distinctive facial features, heart abnormalities, and gastrointestinal disorders. X-linked creatine deficiency is caused by changes (mutations) in the SLC6A8 gene and is inherited in an X-linked manner. Treatment with high doses of creatine monohydrate, L-arginine, and L-glycine has been used to treat some of the symptoms associated with X-linked creatine deficiency with variable success.^[1]^[2]^[3]

Last updated: 11/5/2015

Symptoms Symptoms

The Human Phenotype Ontology (HPO) provides the following list of features that have been reported in people with this condition. Much of the information in the HPO comes from Orphanet, a European rare disease database. If available, the list includes a rough estimate of how common a feature is (its frequency). Frequencies are based on a specific study and may not be representative of all studies. You can use the MedlinePlus Medical Dictionary for definitions of the terms below.

Signs and Symptoms	Approximate number of patients (when available)
Abnormality of creatine metabolism	Very frequent (present in 80%-99% of cases)
Delayed speech and language development	Very frequent (present in 80%-99% of cases)
Intellectual disability	Very frequent (present in 80%-99% of cases)
Seizures	Very frequent (present in 80%-99% of cases)
Aganglionic megacolon	Frequent (present in 30%-79% of cases)
Ataxia	Frequent (present in 30%-79% of cases)
Athetosis	Frequent (present in 30%-79% of cases)
Autistic behavior	Frequent (present in 30%-79% of cases)
Cachexia	Frequent (present in 30%-79% of cases)
Chorea	Frequent (present in 30%-79% of cases)
Constipation	Frequent (present in 30%-79% of cases)
Dystonia	Frequent (present in 30%-79% of cases)
Hyperactivity	Frequent (present in 30%-79% of cases)
Hypertonia	Frequent (present in 30%-79% of cases)
Ileus	Frequent (present in 30%-79% of cases)
Malar flattening	Frequent (present in 30%-79% of cases)
Muscular hypotonia	Frequent (present in 30%-79% of cases)
Open mouth	Frequent (present in 30%-79% of cases)
Self-mutilation	Frequent (present in 30%-79% of cases)
Joint hyperflexibility	Occasional (present in 5%-29% of cases)
Mask-like facies	Occasional (present in 5%-29% of cases)
Microcephaly	Occasional (present in 5%-29% of cases)
Ptosis	Occasional (present in 5%-29% of cases)
Redundant skin	Occasional (present in 5%-29% of cases)
Abnormality of metabolism/homeostasis	-
Aggressive behavior	-
Attention deficit hyperactivity disorder	-
Broad forehead	-
Delayed myelination	-
Exotropia	-
Failure to thrive	-
Feeding difficulties in infancy	-
Gait disturbance	-
Hypermetropia	-
Hypoplasia of the corpus callosum	-
Impaired social interactions	-
Infantile onset	-
Joint hypermobility	-
Long face	-
Midface retrusion	-
Motor delay	-
Myopathic facies	-
Narrow face	-
Neonatal hypotonia	-
Pes cavus	-
Poor hand-eye coordination	-
Spasticity	-
Tall stature	-
Underfolded superior helices	-
Vomiting	-
X-linked recessive inheritance	-

Last updated: 9/1/2017

Diagnosis Diagnosis

Making a diagnosis for a genetic or rare disease can often be challenging. Healthcare professionals typically look at a person’s medical history, symptoms, physical exam, and laboratory test results in order to make a diagnosis. The following resources provide information relating to diagnosis and testing for this condition. If you have questions about getting a diagnosis, you should contact a healthcare professional.

Testing Resources

The Genetic Testing Registry (GTR) provides information about the genetic tests for this condition. The intended audience for the GTR is health care providers and researchers. Patients and consumers with specific questions about a genetic test should contact a health care provider or a genetics professional.

Newborn Screening

Baby's First Test is the nation's newborn screening education center for families and providers. This site provides information and resources about screening at the local, state, and national levels and serves as the Clearinghouse for newborn screening information.
National Newborn Screening and Global Resource Center (NNSGRC) provides information and resources in the area of newborn screening and genetics to benefit health professionals, the public health community, consumers and government officials.

Treatment Treatment

The resources below provide information about treatment options for this condition. If you have questions about which treatment is right for you, talk to your healthcare professional.

Management Guidelines

GeneReviews provides current, expert-authored, peer-reviewed, full-text articles describing the application of genetic testing to the diagnosis, management, and genetic counseling of patients with specific inherited conditions.

Do you have updated information on this condition? Let us know.

Organizations Organizations

Support and advocacy groups can help you connect with other patients and families, and they can provide valuable services. Many develop patient-centered information and are the driving force behind research for better treatments and possible cures. They can direct you to research, resources, and services. Many organizations also have experts who serve as medical advisors or provide lists of doctors/clinics. Visit the group’s website or contact them to learn about the services they offer. Inclusion on this list is not an endorsement by GARD.

Organizations Supporting this Disease

Association for Creatine Deficiencies
1024 Bayside Dr.
Suite 532
Newport Beach, CA 92660
E-mail: kim@creatineinfo.org
Website: http://creatineinfo.org/

Do you know of an organization? Send us your suggestions.

Living With Living With

Living with a genetic or rare disease can impact the daily lives of patients and families. These resources can help families navigate various aspects of living with a rare disease.

Genetics Resources

To find a medical professional who specializes in genetics, you can ask your doctor for a referral or you can search for one yourself. Online directories are provided by GeneTests, the American College of Medical Genetics, and the National Society of Genetic Counselors. If you need additional help, contact a GARD Information Specialist. You can also learn more about genetic consultations from Genetics Home Reference.

Learn More Learn More

These resources provide more information about this condition or associated symptoms. The in-depth resources contain medical and scientific language that may be hard to understand. You may want to review these resources with a medical professional.

Where to Start

Genetics Home Reference (GHR) contains information on X-linked creatine deficiency. This website is maintained by the National Library of Medicine.

In-Depth Information

The Monarch Initiative brings together data about this condition from humans and other species to help physicians and biomedical researchers. Monarch’s tools are designed to make it easier to compare the signs and symptoms (phenotypes) of different diseases and discover common features. This initiative is a collaboration between several academic institutions across the world and is funded by the National Institutes of Health. Visit the website to explore the biology of this condition.
Online Mendelian Inheritance in Man (OMIM) is a catalog of human genes and genetic disorders. Each entry has a summary of related medical articles. It is meant for health care professionals and researchers. OMIM is maintained by Johns Hopkins University School of Medicine.
Orphanet is a European reference portal for information on rare diseases and orphan drugs. Access to this database is free of charge.
PubMed is a searchable database of medical literature and lists journal articles that discuss X-linked creatine deficiency. Click on the link to view a sample search on this topic.

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