Seizures may be just one symptom of a rare genetic disorder called glucose transporter type 1 deficiency syndrome (Glut1 DS).

Learning About Glut1 Deficiency Syndrome

Many neurologic conditions share the symptoms of glucose transporter type 1 deficiency syndrome (Glut1 DS), a rare genetic disorder. In people with Glut1 DS, glucose is not adequately transported from the bloodstream into brain cells. Because glucose is the primary source of energy for the brain, the brain receives inadequate energy in people affected by Glut1 DS.

Glut1 DS symptoms include:

Seizures

A variety of seizure types may occur in Glut1 DS, including myoclonic, atonic, focal, and generalized tonic-clonic. Absence seizures, in which a person appears to lose awareness or stares into space and is generally unresponsive, are also common in Glut1 DS. These can happen at a very young age as well (under age 3 years). However, not all people affected by Glut1 DS have seizures. (Learn about different types of seizures.)

Developmental delay

Children affected by Glut1 DS may experience motor (movement) and developmental delay including learning disabilities and language difficulties. Most children can have these issues.

Movement disorders

People with Glut1 DS may experience abnormal limb movements such as twitching, flailing, writhing, and poor balance. These can be ongoing or occasional. Problems walking or running may be a sign of a movement disorder. Additionally, abnormal, involuntary eye movements that cannot be controlled have been observed in people with Glut1 DS.

Diagnosis of Glut1 DS

A genetic test (SLC2A1) can help identify Glut1 DS as the underlying cause of neurologic problems in people who have seizures or other symptoms but do not respond to medications. In the past (and still once in a while), the diagnosis was made by lumbar puncture looking for a low glucose level compared to blood.

Treatment of Glut1 DS

The only approved treatment and treatment of choice is the use of high fat, low-carbohydrate diets such as the ketogenic diet. Some people and centers have also seen success using the modified Atkins diet for Glut1 DS. This is a medical diet that requires supervision and most children with Glut1 DS regularly monitor ketones and remain on the diet for years or decades. Seizures, movement problems and learning issues can all improve with the ketogenic diet. Alternative options such as C7 oils are under study but at this time do not replace the use of dietary therapy

For more information:

Authored by: Eric Kossoff MD | Ketogenic Diet Editor