Ketogenic Diet in Lafora Disease

Study Summary

This study will examine the effect of a restricted-carbohydrate diet (ketogenic diet) on Lafora disease-a severe neurological disease in which brain cells die because of abnormal accumulation of glucose (a type of sugar). Patients with Lafora disease have rapid neurological deterioration with myoclonus (brief muscle jerks), seizures and mental decline. At present there is no treatment to halt disease progression. Patients 10 years of age and older with relatively advanced Lafora disease may be eligible for this study. Participants will be admitted to the Clinical Center for the first 4 weeks of this 6-month study for baseline testing and to start the ketogenic diet. They will have a complete medical history and physical examination, plus a detailed neurological examination and blood and urine tests. Procedures include: * Magnetic resonance imaging (MRI) brain scans to provide information about brain chemistry * Lumbar puncture (spinal tap) to analyze chemicals in cerebrospinal fluid * Metabolic and endocrinological tests, including a glucose tolerance test, to evaluate the body's response to a large intake of oral glucose * Standard neuropsychological tests * Magnetic resonance spectroscopy of the brain and muscle * Electroencephalography (EEG) to measure brain wave activity * Electromyography (EMG) to measure muscle activity * Evoked potentials (SEP and VEP) to study brain responses to mild electric or visual stimulation. Transcranial magnetic stimulation (magnetic stimulation of the brain) may also be done to study the function of the brain cortex (outer nervous tissue of the brain) and the effects of treatment on brain excitability. The ketogenic diet will begin after the tests are completed. The diet provides mainly fats to fuel the body, plus the recommended amount of protein and minimum carbohydrate. Vitamin and mineral supplements are provided to meet daily requirements. After 2 weeks on the diet, the patient will be discharged from the hospital and seen