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Abnormal carbohydrate structures known as polyglucosan bodies (PGBs) are associated with neurodegenerative disorders, glycogen storage diseases (GSDs), and aging. A hallmark of the GSD Lafora disease (LD), a fatal childhood epilepsy caused by recessive mutations in the EPM2A or EPM2B genes, are cytoplasmic PGBs known as Lafora bodies (LBs). LBs result from aberrant glycogen metabolism and drive disease progression. They are abundant in brain, muscle and heart of LD patients and Epm2a(−/−) and Epm2b(−/−) mice. LBs and PGBs are histologically reminiscent of starch, semicrystalline carbohydrates synthesized for glucose storage in plants. In this study, we define LB architecture, tissue-specific differences, and dynamics. We propose a model for how small polyglucosans aggregate to form LBs. LBs are very similar to PGBs of aging and other neurological disorders, and so these studies have direct relevance to the general understanding of PGB structure and formation.

We report a case of two siblings with progressive myoclonus epilepsy whose parents were not consanguineous. Their clinical symptoms were typical of Lafora disease (LD), but skin biopsies revealed no Lafora bodies. Whole-exome sequencing identified a recurrent homozygous frameshift variant in the NHLRC1 gene in both siblings. The genetic analysis was useful for the diagnosis of LD, as neither consanguinity nor Lafora bodies were found.

11 páginas, 7 figuras. This is a pre-copyedited, author-produced version of an article accepted for publication in Human Molecular Genetics following peer review. The version of record Rubio-Villena C., Viana R., Bonet J., Garcia-Gimeno M.A., Casado M., Heredia M.,Sanz P. (2018). Astrocytes: new players in progressive myoclonus epilepsy of Lafora type. Hum Mol Genet 27(7): 1290-1300, is available online at: http://dx.doi.org/10.1093/hmg/ddy044, Lafora disease (LD) is a fatal form of progressive myoclonus epilepsy characterized by the accumulation of insoluble poorly branched glycogen-like inclusions named Lafora bodies (LBs) in the brain and peripheral tissues. In the brain, since its first discovery in 1911, it was assumed that these glycogen inclusions were only present in affected neurons. Mouse models of LD have been obtained recently, and we and others have been able to report the accumulation of glycogen inclusions in the brain of LD animals, what recapitulates the hallmark of the disease. In this work we present evidence indicating that, although in mouse models of LD glycogen inclusions co-localize with neurons, as originally established, most of them co-localize with astrocytic markers such as glial fibrillary acidic protein (GFAP) and glutamine synthase. In addition, we have observed that primary cultures of astrocytes from LD mouse models accumulate higher levels of glycogen than controls. These results suggest that astrocytes may play a crucial role in the pathophysiology of Lafora disease, as the accumulation of glycogen inclusions in these cells may affect their regular functionality leading them to a possible neuronal dysfunction., This work was supported by grants from the Spanish Ministry of Economy and Competitiveness SAF2014-54604-C3-1-R, a grant from Generalitat Valenciana (PrometeoII/2014/029), a grant form Fundación Ramón Areces (XVIII Concurso Nacional Ayudas Investigacion Ciencias Vida y Materia) and a grant from the National Institute of Health (NIH-NINDS) P01NS097197, which established the Lafora Epilepsy Cure Initiative (LECI), to PS and grants SAF2016-75004-R and Contribution to COST Action CA15203 MITOEAGLE to MC.

In 1911, the Spanish neurologist-pathologist Gonzalo Lafora, working at the then Government Hospital for the Insane in Washington DC, first described the progressive myoclonus epilepsy that would later bear his name (Lafora, 1911). The journey to understand this disease started with Lafora’s detailed neuropathological description of the large and profuse inclusions (Fig. 1) that would come to be known as Lafora bodies. The odyssey has visited many a shore, and the latest and most mysterious is revealed by Javier Gayarre et al. (2014) in this issue of Brain . Figure 1 Lafora bodies as drawn by Lafora in his original manuscript (Lafora, 1911). Whereas the ‘amyloid’ plaques of Alzheimer’s disease are not in fact amyloid (starch), Lafora bodies, by contrast, are. Lafora bodies are composed of hyperphosphorylated and malformed glycogen molecules. These abnormal starch-like polyglucosans aggregate to form insoluble masses, which over time accumulate inside neuronal somata and dendrites. Lafora disease is caused by loss-of-function mutations in …

Polyglucosan bodies (Lafora bodies) were identified in a juvenile gray-headed flying fox ( Pteropus poliocephalus) with neurological signs. The structures were only noted in the brain stem, and no associated degenerative changes were present. These structures have not been previously identified in any species in the order Chiroptera.

Summary A longitudinal clinicoelectrophysiologic study was undertaken of a 15-year 2-month-old girl with Lafora disease who was diagnosed by skin biopsy and an immunohistochemical method with antisera against Lafora bodies. From age 10 years 5 months, 4 months after onset, EEG disclosed progressive deterioration of background activity and incremental increase in epileptic discharges. Photosensitivity was unique: Occipital spikes and diffuse spike-wave discharges were provoked by low-frequency repetitive photic stimuli but without elicitation of myoclonic seizures. Photosensitivity completely disappeared after age 13 years 10 months. High-voltage somatosensory evoked potentials (SEPs) and high-voltage flash visual evoked potentials (F-VEPs) were seen before age 13. After age 13, progressive prolongation of I-III and I-V interpeak latencies of auditory brainstem responses (ABRs), progressive prolongation of latencies of photoevoked eyelid microvibrations, delayed latencies of pattern-reversal visual evoked potentials, and a decrease in the V/I amplitude ratio of ABRs and the previously high F-VEP amplitudes were observed. RESUME Les auteurs ont suivi une jeune fille âgee de 15 ans et 2 mois, Presentant une maladie de Lafora diagnostiquee par biopsie cutanee et etude immunohistochimique au moyen d'un serum reagissant sur les corps de Lafora. A partir de l'âge de 10 ans et 5 mois, 4 mois apres le debut de la maladie, l'EEG a mis en evidence une deterioration progressive de l'activite de fond et une augmentation progressive des decharges epileptiques. Une photosensibilite tres particuliere a ete mise en evidence: des Pointes occipitales et des pointes-ondes diffuses etaient provoquees par la stimulation lumineuse intermittente a basse frequence, sans provoquer toutefois de crises myocloniques, cette photosensibilite a disparu completement apres l'âge de 13 ans et 10 mois. Des potentiels evoques somato-sensitifs de haut voltage et des potentiels evoques visuels au flash de haut voltage ont ete enregistres avant l'âge de 13 ans. Apres cet âge, les auteurs ont constate un allongement progressif des latences interpics I-III et I-IV des potentiels evoques auditifs precoces, un allongement progressif des latences des microvibrations palpebrales evoquees par la lumiere, un allongement des latences des potentiels evoques visuels par inversion de pattern, et une diminution de l'amplitude du rapport V/I des potentiels evoques auditifs precoces et des amplitudes des potentiels evoques visuels au flash. RESUMEN Se ha realizado un estudio longitudinal clinico-electrofisiologico en una nina de 15 anos y 2 meses de edad que padecia la enfermedad de Lafora diagnosticada mediante una biopsia cutanea y un metodo histoquimico con antisuero anticuerpos de Lafora. Desde la edad de 10 anos y 5 meses, 4 meses despues del comienzo de la enfermedad, aaparecio un deterioro progresivo de la actividad de fondo con un incremento de las descargas epilepticas. La fotosensibilidad fue muy especial: puntas occipitales y descargas difusas punta-onda fueron provocadas mediante estimulacion fotica repetitiva efectiva, de baja frecuencia, pero sin que se observaran ataques mioclonicos. La fotosensibilidad desaparecio completamente despues de la edad de 13 anos y 10 meses. Antes de la edad de 13 anos se observaron potenciales evocados somatosensoriales de alto voltaje y potenciales evocados visuales (F-VEPs) tras flash de alto voltaje. Despues de la edad de 13 anos se observaron: una progresiva prolongacion de las latencias interpicos de I-III y I-V de las respuestas auditivas de tronco cerebral (APRs), una prolongacion progresiva de las latencias de las vibraciones de los parpados evocadas foticamente, un retraso de las latencias de los potenciales evocados visuales inducidos por patrones graficos y una reduccion de la relacion V-I de los ABRs y de las previas amplitudes de los F-VEP. ZUSAMMENFASSUNG Eine klinisch-elektrophysiologische Langzeitstudie wurde bei einem jetzt 15 Jahre alten Madchen mit Lafora-Erkrankung durch gefuhrt. Die Diagnose war durch Hautbiopsie un durch immunhistochemische Methoden mit Antiseren gegen Laforakorper gestellt worden. Im Alter von 10,5 Jahren, 4 Monate nach Auftreten der Erkrankung, zeigte das EEG einen progredienten Abbau der Grundaktivitat und allmahliche Zunahme epileptischer Entladungen. Die Fotosensibilitat war auffallig: durch langsame repetitive Stimuli wurden occipitale spikes und diffuse spike-waves Entladungen provoziert ohne Auslosung einer myoklonischen Reaktion. Im Alter von 13,10 Jahren verschwand die Fotosensibilitat vollstandig. Amplitudenhohe somatosensorische EP und hohe Blitz-VEP wurden vor dem Alter von 13 Jahren und danach beobachtet. Die AEP zeigten allmahliche Verlangerung der I-III und I-V Latenzen, ferner eine Verlangerung der Licht-evozierten Augenlid-Mikrovibrationen und verzogerte Latenzen der VEP bei Musterumkehr. Ein Abfall der Amplitudenkorrelation V/1 der AEP und der Amplituden der F-VEP wurde ebenfalls festgestellt.

Lafora bodies (polyglucosan deposits) were identified in the brain of a young adult cat with neurologic signs characterized by intermittent but progressively worsening head and body tremors. The cerebellar cortex was the most severely affected area of brain, and the deposits were identified within Purkinje cell bodies and processes and throughout the neuropil. The association of Lafora bodies with neurologic signs, occurrence of deposits within neuronal perikarya, and distribution primarily within the cerebellar cortex are features distinct from the more commonly recognized situation in which Lafora bodies occur as incidental lesions in cats.

Lafora disease (LD) is an inherited and fatal form of neurodegenerative disorder characterized by the presence of an abnormal form of glycogen inclusions, called Lafora bodies, in neurons and other tissues. While Lafora bodies have been thought to underlie the neuropathology in LD, the specific process by which these inclusions might affect the neuronal functions was not very well understood. Here we review one of our recent studies on the LD animal model, wherein we have shown that the Lafora bodies might contribute to the impairment in the endosomal-lysosomal and autophagy pathways.

Background Lafora Disease (LD) is a fatal teenage-onset progressive myoclonus epilepsy. It is characterized by the formation of Lafora bodies (LBs), deposits of abnormally branched, insoluble, hyperphosphorylated glycogen-like polymers that are generally believed to trigger the development of the clinical symptoms of LD. 58% and 35% of the LD cases are caused by mutations in EPM2A (laforin) and EPM2B (malin), respectively. However, little is known about their function in LB formation. Two different mechanisms have been proposed to explain the accumulation of insoluble LBs: first, excessive glycogen phosphorylation and, second, an imbalance between glycogen synthesizing enzymes. The present study aims at the identification of proteins involved in the molecular mechanisms leading to LB formation and appearance of LD and the phosphorylation of glycogen.

Summary: Since age 12 years, a 25-year-old woman had a syndrome with myoclonic epilepsy, cerebellar signs, and spontaneous myoclonus. Skin biopsy showed typical Lafora bodies (LB), but she lacked a progressive course and mental impairment, hallmarks of Lafora disease. Lysosomal enzyme assays showed low level arylsulfatase A (ASA) activity. DNA study disclosed a homozygous ASA Pd genotype. Both parents carried one Pd allele. The still-unknown relationship between the pathologic level of ASA activity and myoclonic epilepsies suggests introduction of ASA assays in patients with PME. RESUMEN Desde la edad de 12 anos una mujer de 25 anos padecio un sindrome con epilepsia mioclonica, trastornos cerebelosos y mioclonias espontaneas. La biopsia cutanea mostro tipicos cuerpos de Lafora pero no presento un cuadro progresivo ni alteraciones mentales, sintomas fundamentales de la enfermedad de Lafora. Los ensayos de enzima lisosomial mostraron niveles bajos de actividad ASA. El estudio de DNA revelo un genotipo homozigotico ASA Pd. Ambos familiares eran portadores del allelo Pd. Todavia permanece desconocida la relacion entre el nivel patologico de la actividad de la ASA y las epilepsias mioclonicas lo que sugiere la introduccion de los ensayos ASA en los pacientes con epilepsia mioclonica progresiva. ZUSAMMENFASSUNG Eine 25 jahrige Frau litt seit ihrem 12. Lebensjahr an einem Syndrom mit myoklonischer Epilepsie, zerebellaren Zeichen und spontanem Myoklonus. Die Hautbiopsie zeigte typische Laforakorper, die Patientin zeigte jedoch keinen progressiven Verlauf und mentalen Abbau, wie sie typisch fur dei Lafora-Erkrankungen sind. Die Bestimmung der lysosomalen Enzyme zeigte eins erniedrigts ASA-Aktivitat. DNA-Untersuchungen schlossen einen homozygoten ASA Pd Genotyp aus. Beide Eltern trugen sin Pd Allel. Die bislang unbekannte Beziehung zwischen pathologischen ASA Werten und myoklonischen Epilepsien legen nahe, ASA Assays bei Patienten mit PME durchzufuhren.

Massive occurrence of polyglucosan bodies (PBs) was found within the surgically removed temporal lobe of a 34 year old woman with complex partial seizures. This peculiar feature is very unusual in neuropathological examinations of epileptogenic foci. This patient could not be included in any of the classic diseases in which PBs are found. She exhibited a localised form of glycogen storage disease.

Summary Sixty-five patients with progressive myoclonus epilepsy without Lafora bodies were examined by the Wechsler Verbal or Terman-Merrill-Lehtovaara scale, and 25 were reexamined after a mean of 6 yr. Intelligence was relatively intact by contrast with the patients' poor physical condition. The estimated I.Q. at the onset was 92, in the low normal range, and it diminished by about 10 points in 10 yr. This diminution had begun before the appearance of clear clinical symptoms. Low test scores correlated significantly (p < 0.01) with duration of the disease and with age. On the Wechsler Verbal Scale, tests of similarities, information, and comprehension were least affected; scores on digit span and arithmetic tests were lowest. Speech was slow and dysarthric and became finally unintelligible. Personality was infantile and mood labile and often depressed. The surprisingly high intelligence differentiates these patients from those having the form of progressive myoclonus epilepsy that occurs with Lafora bodies. The two diseases seem to be distinct clinical and histopathologic entities. REsume 65 sujets avec une epilepsie myoclonique progressive sans corps de Lafora, ont ete examines avec l'echelle verbale Wechsler ou Terman-Merrill-Lehtovaara, et 25 ont ete examines a nouveau en moyenne 6 ans apres. L'intelligence etait relativement intacte en contraste avec les mauvaises conditions psychiques des sujets. Le Q.I. au debut etait environ G 92, dans les limites inferieures de la normale. Des pauvres performances etaient en correlation significative (p < 0.01) avec la duree de la maladie et l'âge. Dans l'echelle verbale de Wechsler, les tests de similitudes, l'information et la comprehension etaient moins atteints; les valeurs des tests, la memoire des chiffres et l'arithmetique, etaient les plus bas. Le langage etait ralenti et avec dysarthrie et devenait a la fin incomprehensible. La personnaliteetait infantile et l'heumeur labile et souvent depressive. Un niveau d'intelligence etonnament eleve differencie ces patients de ceux qui ont une forme de myoclono-epilepsie progressive avec corps de Lafora. Les deux maladies sont des entites distinctes du point de vue clinique et histo-pathologique. RESUMEN Utilizando la escala verbal de Wechsler o la de Terman-Merrill-Lehtovaara se han examinado 65 enfermos con epilepsyia mioclonica progresiva sin cuerpos de Lafora, 25 de los cuales fueron reexaminados despues de un promedio de 6 anos. La inteligencia estaba relativamente conservada, hecho que contrastaba con el considerable deterioro fisico de los enfermos. Al principio del estudio el Cociente Intelectual (IQ) fue de 92, normal bajo, disminuyendo 10 puntos al cabo de 10 anos. Se aprecio una significativa correlateon (p < 0.01) entre los IQ bajos, la duracion de la enfermedad y la edad de los enfermos. En la escala verbal de Wechsler, resultaron menos afectados los tests de semejanzas, information y comprension, mientras que los resultados mas bajos se obtuvieron en pruebas aritmeticas. El lenguaje era disartrico y lento llegando, finalmente, a ser incomprensible. La personalidad era infantil y el animo labil y frecuentemente deprimido. La inteligencia sorprendentemente alta diferencia a este tipo de enfermos con los que padecen la forma progresiva de epilepsyia mioclonica con cuerpos de Lafora. Estas dos enfermedades constituyen entidades clinicas e histopatologicas distintas. ZUSAMMEnfassung 65 Patienten mit progressiver Myoklonusepilepsie ohne Laforakorperchen wurden psychologisch untersucht mit dem verbalen Wechslertest oder der Terman-Merrill-Lehtovaara-Skala. 25 von ihnen wurden nach einer durchsehnittlichen Zeitdauer von 6 Jahren nachuntersucht. Im Gegensatz zu der schweren korperlichen Beeintrachtigung war die Intelligenz relativ intakt. Der durchschnittliche IQ lag im Beginn mit 92 im unteren Normbereich. Er verminderte sich um etwa 10 Punkte in 10 Jahren. Niedrige Testergebnisse korrelierten signifikant mit der Dauer der Erkrankung und mit dem Alter (p < 0.01). Im Wechslerverbaltest waren die Untertests fur Ahnlichkeiten, Informatione und Verstandnis am wenigsten beeintrachtigt. Die Scores fur Zahlennachsprechen und Rechnen lagen am niedrigsten. Die Sprache war langsam und dysarthrisch und wurde schliesslich unverstandlich. Die Personlichkeit war infantil, die Stimmung labil und haufig depressiv. Die uberraschenderweise hohe Intelligenz unterscheidet diese Patienten von solchen mit einer progressiven Myoklonusepilepsie, bei der Lafora-korperchen gefunden wurden. Beide Erkrankungen sind klinisch und histopathologisch zu unterscheidende Entitaten.

Seven cases of progressive familial myoclonus epilepsy occurring in three families are presented. The patients were in different stages of the illness. The EEG was abnormal in all. It is suggested that these cases belong clinically to the Lafora bodies group. Nystagmus and optic atrophy, seen in one patient, have not been described previously. Myoclonic jerks did not respond to treatment with diazepam and ethosuximide.

Foram feitos estudos neuropatológicos em dois casos de pacientes que apresentaram encefalopatia mioclônica pós-anóxica (síndrome de Lance-Adams). O encéfalo mostrou lesões neuronais difusas, comprometendo principalmente o córtice, tálamo e estruturas sub-talâmicas, desde lesões discretas caracterizadas pela presença de vacúolos intracitoplasmáticos (primeira alteração vista na anoxia) até neurônios totalmente degenerados, notando-se vários neurônios com lesões clássicas de isquemia. A presença de material de inclusão anfofílica discretamente PAS positiva observado no citoplasma neuronal foi diferente das inclusões verificadas nos casos de epilepsia mioclônica com corpúsculos de Lafora. Não conseguimos identificar a constituição destas inclusões, apesar de serem feitos diferentes métodos de coloração. Não encontramos também, na literatura, referência a tal tipo de inclusão. Foram também encontradas alterações vasculares, consistindo de vasos proliferados com células endoteliais tumefeitas. Tais células apresentaram-se com disposição anárquica, provavelmente devidas à anoxia isquêmica. A diferença dos achados anatomopatológicos, entre os casos 1 e 2, são provavelmente decorrentes do mecanismo diverso da instalação da anoxia. Two cases of Lance-Adams syndrome with anatomopathologic study are reported. There were evidences of diffuse neuronal degeneration in the brain. These changes were most seen in the neurones of the cortical layers, thalamus and subthalamic nuclei. The cells changes were similar of those seen in ischaemic disease. Some neurones showed intracytoplasmatic inclusions staining with the P.A.S. method. These inclusions were readily distinguished from the Lafora bodies.

Sections containing Lafora bodies were exposed to the action of amylolytic enzymes. These enzymes split the glucose linkages of glucose polymers (polyglucosans). The following ultrastructural changes were observed: ( a) the fibrils of Lafora bodies were greatly reduced in number; ( b) the staining intensity of the fibrils was reduced; ( c) the amorphous densities were no longer seen. The evidence suggests that the fibrils and amorphous densities of Lafora bodies are both polyglucosan in nature. Lafora bodies resemble corpora amylacea in this respect.

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A case is reported of an 18 year old man with progressive myoclonus epilepsy. Histopathological examination revealed the presence of numerous Lafora bodies in the cerebellar granular layer, without other significant changes in the central nervous system or in other organs.

Summary: Lafora disease is an autosomal recessive and progressive degenerative disorder of the central nervous system (CNS). The pathogenic mechanism has been presumed to be an inborn error of carbohydrate metabolism, although this has never been proved. In a case of proven Lafora disease, pyruvate metabolism, which has a central position in carbohydrate metabolism, was studied in body fluids under various conditions and in brain biopsy material. No abnormalities in this metabolic pathway were found. This finding plus earlier reports in the literature exclude a defect in glycolysis; thus, a disturbance of carbohydrate metabolism as the pathogenic mechanism of Lafora disease is unlikely RESUME La maladie de Lafora est une affection autosomique recessive degenerative et progressive du systeme nerveux central. Le mecanisme pathogenique est vraisemblablement represente par une erreur innee du metabolisme qui n'a jamais ete prouvee. Dans un cas de Lafora confirme, les auteurs ont etudie le meta-bolisme du pyruvate, qui occupe une position centrale dans le metabolisme des glucides, dans les liquides biologiques et a par-tir une biopsie cerebrale. lis n'ont pas constate anomalie dans le meltabolisme du pyruvate. Ces resultats, joints a des travaux anterieurs de la Litterature, excluent hypothese un RESUMEN La enfermedad de Lafora consiste en un proceso degenerativo del Sistema Nervioso Central de naturaleza progresiva y debido a mecanismos hereditarios autosdmicos recesivos. Los mecanismos patogenicos parecen corresponder a un defecto congenita del metabolismo de los carbohidratos a pesar de que nunca nan sido probados. En un caso de enfermedad de Lafora compro-bado patologicamente, se ha estudiado el metabolismo del piru-vato, que ocupa un lugar central en el metabolismo de los carbohidratos, en diversos fluidos corporales bajo condiciones di-versas y tambten en material cerebral de biopsia sin que se encontraran anomalfas de las vias metaolicas. Estos hallazgos unidos a informes previos de la literature excluyen un defecto en la glicolisis por lo que un trastorno en el mecanismo de los carbohidratos, como mecanismo patogenico en la enfermedad de Lafora parece improbable. ZUSAMMENFASSUNG Die Lafora-Erkrankung ist eine autosomal rezessive und progressiv-degenerative Erkrankung des ZNS. Als pathogenetischer Mechanismus wird bislang unbewiesen eine angeborene Stoning des Kohlehydratstoffwechsels vermutet. Bei einem erwiesenen Fall einer Lafora-Erkrankung wurde der Pyruvat-Metabolismus, der eine zentrale Stelle im Kohlehydrat-Metabolismus einnimmt, sowohl in Korperflussigkeiten unter unterschiedlichen Bedin-gungen als auch im bioptischen Hirngewebe untersucht. Es wur-den keine Abnormalitaten dieses Stoffwechselweges gefunden. Dies last zusammen mit alteren Berichten der Literatur einen Glycolysedefekt ausschliesen. Somit scheint eine Stoning des Kohlehydrat-Stoflwechsels als pathogenetischer Mechanismus fur die Lafora-Erkrankung unwahrscheinlich

SUMMARY 1 In the brains of two siblings suffering from progressive myoclonus epilepsy, cells were observed which suggested the presence of a storage process. A fragment of the brainstem of a four-day-old nephew of these patients also showed “storage cells”. The neuropathological aspects are briefly described and found to correspond with classical descriptions of progressive myoclonus epilepsy with Lafora bodies in the nervous system. 2 Complete anatomical investigation of the visceral organs was possible in only one of the siblings. The heart contained deposits which were strongly PAS-positive and remained so after treatment of the specimen with saliva. In the liver of this patient, two different types of PAS-positive products could be found: (a) products which remain PAS-positive after treatment of the specimens with saliva and (b) products resembling glycogen in being saliva- and acid formaldehyde-labile. The latter type of product was found in cells arranged in insular patterns. 3 The hexosamine content of the brains of the two siblings and of the heart of one of them was normal. The liver of the last named patient contained an excess of nonlipid hexosamine. 4 It is tentatively suggested that a pathological alteration of glycogen metabolism existed in one of the patients described. This hypothesis could not be verified in the other two patients from this family who came to autopsy, because the preservation of the post mortem material was not appropriate for histochemical or biochemical studies. RESUME 1 Des cellules temoignant de la presence d'une thesaurismose ont ete observees dans le cerveau de deux malades (frere et soeur) atteints d'epilepsie myoclonique et le meme type de cellules a ete retrouve dans le tronc cerebral d'un cousin de ces malades, âge de quatre jours. L'aspect neuro-pathologique est resume en bref. II correspond a la description classique de l'epilepsie myoclonique progressive avec corpuscules de Lafora dans le systeme nerveux. 2 Un examen anatomique complet des organes visceraux n'a ete possible que chez Tun des malades adultes. Le coeur contenait des depots fortement PAS-positifs, resistant au traitement de la coupe par de la salive. On a trouve dans le foie de ce malade deux types diffeArents de produits PAS-positifs: (a) des produits restant PAS-positifs apres le traitement des coupes par la salive et (b) des produits ressemblant au glycogene en ce sens qu'ils disparaissent apres le traitement par la salive et par le formaldehyde acide. Ce dernier type de produit est present dans des cellules rangees selon un type insulaire. 3 Le taux d'hexosamine du cerveau de chacun des deux malades adultes, ainsi que celui du coeur de l'un d'eux etaient normaux. Le taux d'hexosamine non-lipidique etait eleve dans le foie de ce malade. 4 L'auteur tend a suggerer, comme hypothese de travail, la presence d'un trouble du metabolisme de glycogene chez l'un des malades decrits. Cette hypothese n'a pu etre confirmee a l'autopsie chez les deux autres malades de cette famille parce que la conservation du materiel post-mortem ne permettait point des etudes histochimiques et biochimiques.

SUMMARY A sister and brother, children of consanguineous parents, were suffering from progressive myoclonus epilepsy. In the boy, the myoclonic jerks of the Unverricht type remained very discrete. In both cases there were numerous Lafora bodies in the brain; one patient in addition showed cardiac and hepatic changes in the form of accumulations of unidentified material. Patients with progressive myoclonus epilepsy who belong to the Lafora group, have similar clinical symptoms and similar microscopic abnormalities in the brain. The clinical picture is characterized by the onset of generalized seizures at age 10–17, myoclonus of the Unverricht type, early dementia, normal ocular fundi and a duration of illness not exceeding 10 years; EEG findings are to some extent characteristic, and remain practically constant during the course of the illness; the disease often is a familial condition; the parents are free of the affection, but often consanguineous. Numerous Lafora bodies in the substantia nigra, dentate nucleus, the entire cerebral cortex and the thalamus are considered by us to be pathognomonic for a particular subgroup of the clinical syndrome progressive myoclonus epilepsy; this probably also applies to the changes in the heart and liver. RESUME Un frere et une soeur, issus de parents consanguins, sont atteints d'une epilepsie myoclonique progressive dont les secousses du type Unverricht sont tres discretes chez le garcon. L'examen anatomique montre de nombreux corpuscules de Lafora dans les deux cerveaux et, chez l'un des malades seulement, des alterations cardiaques et hepatiques representees par l'accumulation d'une substance non identifyee. Ces deux observations confirment le fait que les malades souffrant d'une epilepsie myoclonique progressive du type Lafora presentent une semeiologie clinique et des anomalies microscopiques cerebrales semblables. L'aspect clinique est caracterise par l'apparition de crises generalisees entre 10 et 17 ans, par des myoclonies du type Unverricht, une demence relativement precoce et un fond d'oeil normal; l'evolution n'excede jamais dix ans. Les donnees de L'E.E.G. sont relativement caracteristiques et restent pratiquement constantes pendant le cours de la maladie. L'affection est souvent familiale, mais elle respecte les parents qui sont frequemment consanguins. L'existence de nombreux corpuscules de Lafora dans la substance noire, dans le noyau dentele, dans le thalamus et dans tout le cortex cerebral est, a notre avis, pathognomonique d'un subgroupe du syndrome clinique d'epilepsie myoclonique progressive; il en va probablement de meme en ce qui concerne les alterations cardiaques et hepatiques.

The diagnosis of Lafora's syndrome, progressive myoclonus epilepsy and intracytoplasmic periodic acid-Schiff-positive inclusions (Lafora bodies), was made by skin biopsy in a 16-year-old girl at the Depts of Pathology and Dermatology, University of Texas Medical Branch, Galveston, TX.