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An elderly man was affected by progressive dementia, motor neuron disease, and sensory abnormalities for about three years, since the age of 59. Seizures or myoclonus were not observed. On postmortem examination, abnormal inclusion bodies which were histologically, histochemically, and ultrastructurally identical to Lafora disease, were seen in neuronal processes throughout the central nervous system (CNS). Unlike classical Lafora's disease, however, their presence was limited to neuronal processes and not in the perikarya. Also, diffuse distribution of these bodies in the CNS differed from classical Lafora's disease, which showed more heavy concentration in the dentate nucleus, thalamus, inferior olive, and substantia nigra. Since it appears that the inclusions were almost identical, the differences in localization and distribution of inclusions may contribute to the differences in symptomatology between the present case and classical cases of Lafora's disease.

Very low levels of arylsulphatase A were found in a young patient with the clinical features of Lafora disease, confirmed by muscle biopsy. The deficiency was shown both in leukocytes and cultured fibroblasts. A cerebroside sulphate loading showed that 93% of [14C]cerebroside sulphate taken up by skin fibroblasts from the patient remained unmetabolized after a 24h pulse, ruling out pseudo-arylsulphatase A deficiency. In the healthy parents and siblings of the patient, biochemical data suggested heterozygosity for arylsulphatase A deficiency. The apparent co-inheritance of arylsulphatase A deficiency and Lafora disease in this family might be the consequence of genetic linkage between the two genes.

Ultrastructural studies of muscle from a patient with Lafora disease showed sheets of glycogen particles and fine granular-filamentous material between myofibrils. These structures were frequently intermingled and stained intensely with silver proteinate, a specific stain for polysaccharides. Methods for isolation of glycogen yielded excessive hexose-releasing material. In chromatographic analysis of a hydrolysate of this material, glucose was the only component sugar. Compared with action on normal muscle glycogen, phosphorylase was ineffective, β-amylase 50% less effective, but α-amylase normally effective in degrading the Lafora polyglucosan. Incubation of muscle homogenate or isolated polyglucosan with a mixture of glucosidases capable of completely degrading normal glycogen (Diazyme) resulted in only 30% digestion of the Lafora polyglucosan. The metabolic error causing the accumulation of anomalous polysaccharide in this generalized storage disease remainsobscure.

Summary Glycogen in the brain and the liver of two autopsied cases of hepatic encephalopathy was studied histochemically and biochemically. 1. Lots of glycogen particles deposited in the liver and in the brain of the cases, particulary in the brain of Case 1 and in the liver of Case 2. Glycogen granules accumulated in the cerebral cortex, especially in the nuclei of Alzheimer's type II glia, in the perivascular space and freely in the tissue. 2. Glycogen was extracted from the brain and from the liver of both cases. The yield from the brain was 0.058% wet weight in Case 1 and 0.072% in Case 2, that from the liver was 0.103% in Case 1 and 4.42% in Case 2 respectively. 3. The structural analysis of the extracted glycogen revealed that the glycogen from the brain of Case 1 and from the brain and the liver of Case 2 had a relatively shorter chain length (unbranched, exterior) of glucose radicals, while that from the liver of Case 1 had a longer chain length which was similar to that from the brain of Lafora disease. This study was supported by the Grant for the research of science from the Department of Education of the Government of Japan.

THE LAFORA body form of myoclonus epilepsy is a genetically-determined (recessive) disease. It usually begins clinically in the teens, and ends fatally two to ten years later. 1,2 Its cardinal clinical features are those of a progressive seizure disorder, with myoclonus, dementia, ataxia, and dysarthria. 3 The round inclusions described by Lafora are the hallmark of this disorder. 1 These Lafora bodies (LFB) occur not only in ganglion cells of the central nervous system, but also in the retinae and in the axones of spinal nerves. Another neuropathological feature is a degeneration of some ganglion cells severe enough to constitute a form of poliodystrophy. The histochemical and chemical nature of LFB have been points at issue. This situation has left unclear the precise relationship between LFB and the pathogenesis of the disease. The purposes of this study are: (1) to note a method for isolating a Lafora body fraction