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Glucose transporter type 1 deficiency syndrome


Other Names:
GLUT1 deficiency syndrome; Encephalopathy due to GLUT1 deficiency; Glucose transport defect, blood-brain barrier; GLUT1 deficiency syndrome; Encephalopathy due to GLUT1 deficiency; Glucose transport defect, blood-brain barrier; De Vivo disease; GLUT-1 deficiency syndrome; Glucose transporter protein syndrome; GLUT1 DS; G1D See More
Categories:
Glucose transporter type 1 deficiency syndrome (GLUT1 deficiency syndrome) is an inherited condition that affects the nervous system. Signs and symptoms generally develop within the first few months of life and may include recurrent seizures (epilepsy) and involuntary eye movements. Affected people may also have microcephaly (unusually small head size) that develops after birth, developmental delay, intellectual disability and other neurological problems such as spasticity, ataxia (difficulty coordinating movements), and dysarthria. Approximately 10% of affected people have the "non-epileptic" form of GLUT1 deficiency syndrome which is associated with all the typical symptoms of the condition without seizures.[1][2] GLUT1 deficiency syndrome is caused by changes (mutations) in the SLC2A1 gene and is inherited in an autosomal dominant manner. Although there is currently no cure for GLUT1 deficiency syndrome, a special diet (called a ketogenic diet) may help alleviate symptoms.[3]
Last updated: 12/7/2015
The most common form of glucose transporter type 1 deficiency syndrome (GLUT1 deficiency syndrome), called the classic type, may be characterized by:[1][3][2]
  • Recurrent seizures (epilepsy) beginning in the first months of life
  • Microcephaly (unusually small head size) that develops after birth
  • Developmental delay
  • Intellectual disability
  • Speech and language impairment
  • Movement abnormalities (i.e. involuntary eye movements, spasticity, ataxia, dystonia)
  • Behavioral problems
Other signs and symptoms may include headaches, confusion, loss of energy and/or myoclonus (muscle twitches).[1]

Approximately 10% of affected people have the non-epileptic form of GLUT1 deficiency syndrome. This form is associated with all the typical symptoms of the condition without seizures.[1][3]
Last updated: 12/8/2015

This table lists symptoms that people with this disease may have. For most diseases, symptoms will vary from person to person. People with the same disease may not have all the symptoms listed. This information comes from a database called the Human Phenotype Ontology (HPO) . The HPO collects information on symptoms that have been described in medical resources. The HPO is updated regularly. Use the HPO ID to access more in-depth information about a symptom.

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Medical Terms Other Names
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HPO ID
80%-99% of people have these symptoms
Abnormal erythrocyte morphology 0001877
Ataxia 0001251
Dystonia 0001332
EEG abnormality 0002353
Encephalopathy 0001298
Global developmental delay 0001263
Hypoglycorrhachia
Low glucose levels in cerebral spinal fluid
0011972
Progressive microcephaly
Progressively abnormally small cranium
Progressively abnormally small skull
[ more ] 		0000253
Spasticity
Involuntary muscle stiffness, contraction, or spasm
0001257
Status epilepticus
Repeated seizures without recovery between them
0002133
30%-79% of people have these symptoms
Choreoathetosis 0001266
Confusion
Disorientation
Easily confused
Mental disorientation
[ more ] 		0001289
Cyanosis
Blue discoloration of the skin
0000961
Delayed speech and language development
Deficiency of speech development
Delayed language development
Delayed speech
Delayed speech acquisition
Delayed speech development
Impaired speech and language development
Impaired speech development
Language delay
Language delayed
Language development deficit
Late-onset speech development
Poor language development
Speech and language delay
Speech and language difficulties
Speech delay
[ more ] 		0000750
Dysarthria
Difficulty articulating speech
0001260
Extrapyramidal dyskinesia 0007308
Generalized hyperreflexia 0007034
Headache
Headaches
0002315
Hemiparesis
Weakness of one side of body
0001269
Intellectual disability
Mental deficiency
Mental retardation
Mental retardation, nonspecific
Mental-retardation
[ more ] 		0001249
Lethargy 0001254
Muscle stiffness 0003552
Paralysis
Inability to move
0003470
Paroxysmal involuntary eye movements 0007704
Seizure 0001250
5%-29% of people have these symptoms
Apraxia 0002186
Autosomal recessive inheritance 0000007
Central apnea 0002871
Myoclonus 0001336
Sleep disturbance
Difficulty sleeping
Trouble sleeping
[ more ] 		0002360
Strabismus
Cross-eyed
Squint
Squint eyes
[ more ] 		0000486
Percent of people who have these symptoms is not available through HPO
Abnormality of metabolism/homeostasis
Laboratory abnormality
Metabolism abnormality
[ more ] 		0001939
Autosomal dominant inheritance 0000006
Babinski sign 0003487
Hyperreflexia
Increased reflexes
0001347
Infantile onset
Onset in first year of life
Onset in infancy
[ more ] 		0003593
Paroxysmal dystonia 0002268
Paroxysmal lethargy 0011973
Postnatal microcephaly 0005484
Specific learning disability 0001328
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Last updated: 7/1/2020
Glucose transporter type 1 deficiency syndrome (GLUT1 deficiency syndrome) is caused by changes (mutations) in the SLC2A1 gene. This gene encodes a protein that helps transport glucose (a simple sugar) into cells where it is used as fuel. The protein is particularly important in the central nervous system since glucose is the brain's main source of energy. SLC2A1 mutations impair the function of the protein. This significantly reduces the amount of glucose available to brain cells leading to the many signs and symptoms associated with GLUT1 deficiency syndrome.[1][4]
Last updated: 12/7/2015
Glucose transporter type 1 deficiency syndrome (GLUT1 deficiency syndrome) is inherited in an autosomal dominant manner.[1] This means that to be affected, a person only needs a change (mutation) in one copy of the responsible gene in each cell. In some cases, an affected person inherits the mutation from an affected parent. Other cases may result from new (de novo) mutations in the gene. These cases occur in people with no history of the disorder in their family. A person with GLUT1 deficiency syndrome has a 50% chance with each pregnancy of passing along the altered gene to his or her child.
Last updated: 12/8/2015
A diagnosis of glucose transporter type 1 deficiency syndrome (GLUT1 deficiency syndrome) is often suspected based on the presence of characteristic signs and symptoms. Additional testing can then be ordered to confirm the diagnosis. This may include a lumbar puncture, specialized blood tests to measure the blood concentration of glucose and genetic testing.[3][2]
Last updated: 12/8/2015

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.
There is currently no cure for glucose transporter type 1 deficiency syndrome (GLUT1 deficiency syndrome); however, a special diet (called a ketogenic diet) may help control symptoms in some affected people.[3] The GLUT1 Deficiency Foundation offers an information page with detailed information regarding the ketogenic diet. Please click on the link to access this resource.     
Last updated: 12/8/2015

Management Guidelines

  • Orphanet Emergency Guidelines is an article which is expert-authored and peer-reviewed that is intended to guide health care professionals in emergency situations involving this condition.  

If you need medical advice, you can look for doctors or other healthcare professionals who have experience with this disease. You may find these specialists through advocacy organizations, clinical trials, or articles published in medical journals. You may also want to contact a university or tertiary medical center in your area, because these centers tend to see more complex cases and have the latest technology and treatments.

If you can’t find a specialist in your local area, try contacting national or international specialists. They may be able to refer you to someone they know through conferences or research efforts. Some specialists may be willing to consult with you or your local doctors over the phone or by email if you can't travel to them for care.

You can find more tips in our guide, How to Find a Disease Specialist. We also encourage you to explore the rest of this page to find resources that can help you find specialists.

Healthcare Resources

Research helps us better understand diseases and can lead to advances in diagnosis and treatment. This section provides resources to help you learn about medical research and ways to get involved.

Clinical Research Resources

  • ClinicalTrials.gov lists trials that are related to Glucose transporter type 1 deficiency syndrome. Click on the link to go to ClinicalTrials.gov to read descriptions of these studies.

    Please note: Studies listed on the ClinicalTrials.gov website are listed for informational purposes only; being listed does not reflect an endorsement by GARD or the NIH. We strongly recommend that you talk with a trusted healthcare provider before choosing to participate in any clinical study.

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

Social Networking Websites

  • RareConnect has an online community for patients and families with this condition so they can connect with others and share their experiences living with a rare disease. The project is a joint collaboration between EURORDIS (European Rare Disease Organisation) and NORD (National Organization for Rare Disorders).

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 Glucose transporter type 1 deficiency syndrome. This website is maintained by the National Library of Medicine.
  • The National Organization for Rare Disorders (NORD) has a report for patients and families about this condition. NORD is a patient advocacy organization for individuals with rare diseases and the organizations that serve them.

In-Depth Information

  • 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.
  • 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 Glucose transporter type 1 deficiency syndrome. Click on the link to view a sample search on this topic.

Questions sent to GARD may be posted here if the information could be helpful to others. We remove all identifying information when posting a question to protect your privacy. If you do not want your question posted, please let us know.

  1. GLUT1 deficiency syndrome. Genetics Home Reference. March 2014; http://ghr.nlm.nih.gov/condition/glut1-deficiency-syndrome.
  2. Glucose Transporter Type 1 Deficiency Syndrome. NORD. 2014; https://rarediseases.org/rare-diseases/glucose-transporter-type-1-deficiency-syndrome/.
  3. Dong Wang, MD, Juan M Pascual, MD, PhD, and Darryl De Vivo, MD. Glucose Transporter Type 1 Deficiency Syndrome. GeneReviews. January 2015; http://www.ncbi.nlm.nih.gov/books/NBK1430/#glut1.Clinical_Description.
  4. What is Glut1 Deficiency?. GLUT1 Deficiency Foundation. http://www.g1dfoundation.org/what-is-glut1-deficiency/what-is-glut1-deficiency/. Accessed 12/7/2015.