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GLUT1 deficiency syndrome
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Reviewed January 2014
What is GLUT1 deficiency syndrome?
GLUT1 deficiency syndrome is a disorder that primarily affects the brain. Affected individuals generally have seizures beginning in the first few months of life. Babies with GLUT1 deficiency syndrome have a normal head size at birth, but growth of the brain and skull is often slow, in severe cases resulting in an abnormally small head size (microcephaly).
People with GLUT1 deficiency syndrome may have developmental delay or intellectual disability. They may also have other neurological problems, such as stiffness caused by abnormal tensing of the muscles (spasticity), difficulty in coordinating movements (ataxia), and speech difficulties (dysarthria). Some experience episodes of confusion, lack of energy (lethargy), headaches, muscle twitches (myoclonus), or involuntary irregular eye movements, particularly during periods without food (fasting).
How common is GLUT1 deficiency syndrome?
GLUT1 deficiency syndrome is a rare disorder. Approximately 500 cases have been reported worldwide since the disorder was first identified in 1991.
What genes are related to GLUT1 deficiency syndrome?
The SLC2A1 gene provides instructions for producing a protein called the glucose transporter protein type 1 (GLUT1). This protein is embedded in the outer membrane surrounding cells, where it transports glucose (a simple sugar) from the blood into the cells for use as fuel.
The GLUT1 protein is involved in moving glucose across the blood-brain barrier, which is the boundary that separates tiny blood vessels (capillaries) from the surrounding brain tissue. Glucose is the brain's main energy source under normal conditions. The blood-brain barrier protects the brain's delicate nerve tissue by preventing many other types of molecules from entering the brain.
SLC2A1 gene mutations reduce or eliminate the function of the GLUT1 protein produced from one copy of the gene in each cell. Having less functional GLUT1 protein reduces the amount of glucose available to brain cells, which affects brain development and function.
Read more about the SLC2A1 gene.
How do people inherit GLUT1 deficiency syndrome?
This condition is inherited in an autosomal dominant pattern, which means one copy of the altered gene in each cell is sufficient to cause the disorder.
This disorder usually results from new mutations in the gene. These cases occur in people with no history of the disorder in their family. In other cases, an affected person inherits the mutation from an affected parent.
Where can I find information about diagnosis or management of GLUT1 deficiency syndrome?
These resources address the diagnosis or management of GLUT1 deficiency syndrome and may include treatment providers.
General information about the diagnosis and management of genetic conditions is available in the Handbook. Read more about genetic testing, particularly the difference between clinical tests and research tests.
To locate a healthcare provider, see How can I find a genetics professional in my area? in the Handbook.
Where can I find additional information about GLUT1 deficiency syndrome?
You may find the following resources about GLUT1 deficiency syndrome helpful. These materials are written for the general public.
You may also be interested in these resources, which are designed for healthcare professionals and researchers.
What other names do people use for GLUT1 deficiency syndrome?
What if I still have specific questions about GLUT1 deficiency syndrome?
Where can I find general information about genetic conditions?
The Handbook provides basic information about genetics in clear language.
These links provide additional genetics resources that may be useful.
What glossary definitions help with understanding GLUT1 deficiency syndrome?
ataxia ; autosomal ; autosomal dominant ; blood-brain barrier ; capillaries ; cell ; deficiency ; developmental delay ; dysarthria ; encephalopathy ; fasting ; gene ; glucose ; involuntary ; lethargy ; microcephaly ; mutation ; myoclonus ; neurological ; protein ; simple sugar ; spasticity ; syndrome ; tissue
You may find definitions for these and many other terms in the Genetics Home Reference Glossary.
See also Understanding Medical Terminology.
References (9 links)
The resources on this site should not be used as a substitute for professional medical care or advice. Users seeking information about a personal genetic disease, syndrome, or condition should consult with a qualified healthcare professional. See How can I find a genetics professional in my area? in the Handbook.