LAFORA'S disease1(progressive myoclonus epilepsy with Lafora inclusion bodies) is a rare hereditary disorder. It can be characterized clinically by the onset in adolescence of myoclonus, convulsions, and progressive dementia with inexorable progression to death within four to ten years. Of the few reported examples of this disease, most have been diagnosed at autopsy and studies have generally been restricted to histopathologic techniques. We recently have studied two patients with Lafora's disease in an attempt more clearly to define the clinical, genetic, and biochemical aspects of this disease.2,3The histology and ultrastructure of biopsy material from cerebral cortex, striated muscle, liver, and other sites were also studied. Because definite abnormalities were noted in many facets of our investigation, we are reporting our observations in detail. Report of Cases CASE 1.— A 19-year-old white boy was admitted to the North Carolina Baptist Hospital in October 1963, for evaluation of