The animated videos in NORD’s Rare Disease Video Library provide brief introductions to rare disease topics for patients, caregivers, students, professionals and the public. NORD collaborates with medical experts, patient organizations, videographers and Osmosis to develop the videos, which are made possible by individual donations, educational grants and corporate sponsorships. NORD is solely responsible for the content.
Glucose transporter type 1 deficiency syndrome (Glut1DS) is a rare genetic metabolic disorder characterized by deficiency of a protein that is required for glucose (a simple sugar) to cross the blood-brain barrier and other tissue barriers. The most common symptom is seizures (epilepsy), which usually begin within the first few months of life. However, the symptoms and severity of Glut1DS can vary substantially from one person to another. For example, some affected individuals may not develop epilepsy. Additional symptoms that can occur include abnormal eye-head movements, body movement disorders, developmental delays, and varying degrees of cognitive impairment, slurred speech and language abnormalities. Glut1DS is caused by changes (mutations) in the SLC2A1 gene and is inherited in an autosomal dominant pattern. Rarely, the condition also may be inherited in an autosomal recessive pattern. Glut1DS does not respond to traditional epilepsy treatments (e.g., anti-seizure medications), but is successfully treated with the ketogenic diet.
Glut1DS was first described in the medical literature in 1991 by Dr. De Vivo, et al. The disorder is also known as De Vivo disease. Glut1DS is classified as an epileptic encephalopathy. Epileptic encephalopathies are a group of disorders in which seizure activity is associated with progressive psychomotor dysfunction. Paroxysmal exercise-induced dyskinesias (PED), also known previously as dystonia 18 and dystonia 9, are now considered part of the Glut1DS spectrum. Epilepsy commonly presents in infancy whereas PED commonly emerges in late childhood and adolescence.