This a genetic condition which affects metabolism of glucose. Glucose is essential for brain function and is transported from the blood to the brain using a protein called GLUT1. In GLUT1 deficiency the glucose supply is impaired and this affects brain development and functioning resulting in seizures early in life in most children and it is rare for seizures not to develop.
Characteristics
Children vary in terms of how they are affected and whether the signs are persistent. Abnormal eye movements may appear before the child develops seizures. Seizures may develop in the first few months although some children may develop seizures later than this, generally in the first few years. Head growth may be slow and linked to developmental delay.
The child may also seem confused upon waking. Abnormal eye movements may be seen in babies and young children. Abnormal limb and body movements, stiffness and posturing may be seen in older children. Some older children may also go on to develop co-ordination problems, ataxia, movement problems and weakness on one side. Cognitive effects such as confusion, learning delay and speech delay may be seen also. Some symptoms will be made worse if a child has not eaten or by tiredness or exertion.
The main seizure types in GLUT1 deficiency are absence seizures; myoclonic seizures and focal seizures. About 1 in 10 children with early onset absence seizures and 1 in 20 children with epilepsy with myoclonic-atonic seizures have GLUT1 deficiency.
Prognosis
Learning issues may be present for children with GLUT1 as may movement disorders.
Diagnosis
While an EEG might be abnormal in children with GLUT1 deficiency it will not be diagnostic of this condition. To test for the level of glucose in the Cerebrospinal Fluid, a lumbar puncture is carried out to see if GLUT1 may be indicated. Since GLUT1 deficiency is related to a mutation on the SLC2A1 which is involved in the production of GLUT1, genetic testing will be arranged.
Treatment
Treatment with Anti-Seizure Medications (ASM’s) is used but is unlikely to control seizures completely in GLUT1 Deficiency Syndrome. Children with movement disorders may need treatment for those also. The ketogenic diet is a main treatment from the outset for the seizures and it may be effective in controlling seizures and optimising cognitive outcome but may need to continued on a long-term basis.
The ketogenic diet (KD) is a high-fat, low-carbohydrate diet. There are several variations such as the classical MCT oil diet, low glycaemic index diet and the modified Atkins diet. It is a non-pharmacological treatment and is used in combination with ASM’s. The diet has been effective at reducing seizures and is regarded as safe with side effects being transient and less likely to lead to cognition difficulties and drowsiness.
Further Information
- Further information on Anti-Seizure Medications and the Ketogenic Diet can be found by visiting the 'Treatment' section of our website.
- Further information on diagnosis can be found by visiting the 'Diagnosis' section of our website.
- Other useful resources surrounding epilepsy can be found throughout our 'Epilepsy Information' section.
- If you need any information or support regarding epilepsy, contact your local Community Resource Officer - you can find their details by visiting the 'Our Local Service' section of our website.