Lafora disease: liver histopathology in presymptomatic children

Lafora disease is an inborn error of carbohydrate metabolism with storage of a polyglucosan in various tissues including brain and liver. Recently, distinctive histopathological changes in liver have been emphasized, and the diagnosis has been confirmed by the relatively simple procedure of percutaneous liver biopsy. We utilized this technique to study three asymptomatic preadolescent children from one family in which older siblings had symptomatic Lafora disease confirmed by brain or liver biopsy. Liver biopsies from the asymptomatic children showed altered hepatocytes identical to those seen in symptomatic subjects, although the cells were considerably less numerous. All three children subsequently became symptomatic. Distinctive liver changes can antedate the onset of symptoms in Lafora disease.     

Lafora disease: Current biology and therapeutic approaches

The ubiquitin system impacts most cellular processes and is altered in numerous neurodegenerative diseases. However, little is known about its role in neurodegenerative diseases due to disturbances of glycogen metabolism such as Lafora disease (LD). In LD, insufficiently branched and long-chained glycogen forms and precipitates into insoluble polyglucosan bodies (Lafora bodies), which drive neuroinflammation, neurodegeneration and epilepsy. LD is caused by mutations in the gene encoding the glycogen phosphatase laforin or the gene coding for the laforin interacting partner ubiquitin E3 ligase malin. The role of the malin-laforin complex in regulating glycogen structure remains with full of gaps. In this review we bring together the disparate body of data on these two proteins and propose a mechanistic hypothesis of the disease in which malin-laforin's role to monitor and prevent over-elongation of glycogen branch chains, which drive glycogen molecules to precipitate and accumulate into Lafora bodies. We also review proposed connections between Lafora bodies and the ensuing neuroinflammation, neurodegeneration and intractable epilepsy. Finally, we review the exciting activities in developing therapies for Lafora disease based on replacing the missing genes, slowing the enzyme – glycogen synthase – that over-elongates glycogen branches, and introducing enzymes that can digest Lafora bodies. Much more work is needed to fill the gaps in glycogen metabolism in which laforin and malin operate. However, knowledge appears already adequate to advance disease course altering therapies for this catastrophic fatal disease.     

Immunocytochemical and lectin-binding studies on Lafora bodies

Antibodies to a range of intermediate filaments and lectins specific for several different carbohydrates were used to study Lafora bodies in two cases of Lafora disease. Positive staining of Lafora bodies was found with antibodies to 160 KD and 200 KD neurofilaments and to desmin. Positive staining with concanavalin A showed different patterns of inhibition with glucose and mannose, suggesting that the latter hexose contributes to the 10% non-glucose carbohydrate content of these bodies.     

Distribution and electron microscopical and immunohistochemical aspects of Lafora bodies in a Lafora patient with a 17-year clinical course

Autopsy was performed on a 30-year-old man who died of Lafora disease. This patient, one of two siblings with Lafora disease, had onset of symptoms at age 13 years and a clinical course of 17 years. He had frequent tonic-clonic convulsions and myoclonus, followed by dementia. Due to dysphagia resulting from strong spasms of the pharyngo-esophageal muscles, he underwent gastrostomy. Routine laboratory data, including liver function tests and an electrocardiogram (ECG), were within the normal range. The autopsy revealed degeneration with polyglucosan accumulations in myocardiac muscle cells, liver cells, and smooth muscle cells of the esophago-gastrointestinal tract, urinary system, and blood vessels, as well as in striated muscle cells in the skeletal muscles and neurons in the nervous system. In the central nervous system (CNS), numerous intraneuronal polyglucosan accumulations (Lafora bodies) were present in the following structures (listed in decreasing order of density): the substantia nigra, olivary nuclei (superior and inferior), vestibular nucleus (medial and lateral), thalamus, globus pallidus (lateral segment), dentate nucleus, gracile and cuneate nuclei, cerebral cortex (frontal, temporal, parietal and occipital), amygdala, nucleus basalis of Meynert, neostriatum, hypothalamus, reticular formation of the brain stem, locus ceruleus, red nucleus, mesencephalic central gray, solitary nucleus, ambiguus nucleus, dorsal vagal nucleus, and some other cranial nerve nuclei. In the mammillary bodies or subthalamic nucleus no perikaryonal Lafora bodies were found, although a considerable number of intraneuritic Lafora bodies were noted. Electron microscopically, Lafora bodies were composed of granular material and irregular filaments (about 6 nm in diameter), which were immunohistochemically positive for ubiquitin and tau. No Lafora bodies were reactive with Gallyas stain. This study is the first to have revealed that in Lafora disease smooth muscle cells can be systemically involved in specific degeneration for Lafora disease. In this patient, severe myoclonus could potentially spread over the pharynx and esophagus and cause pharyngo-esophageal spasm and dysphagia. Because of the very long clinical course, the histopathology of this patient may represent the full extension of the degeneration that is specific for Lafora disease.     

Torpide verlaufende Degeneration des äußeren Pallidumgliedes mit Bielschowsky-Körperchen

In a 60-year man with a very slowly progressive motor disturbance probably of torsion systonic or choreoathetotic type which started in childhood, we found an isolated degeneration of the exterior pallidum with intraneuronal deposition of Bielschowsky bodies and only slight deficit of neurons. The Bielschowsky bodies show the same structure as corpora amylacea and Lafora bodies. They might also be the result of a cellular disturbance mainly concerning the carbohydrate metabolism. In this case they are localised only in the neurons of the exterior part of the pallidum--in contrast to the organogenitically otherwise deriving (from the nucl. entopeduncularis) intact neurons of the pallidum internum--and they induce, after an excessive accumulation of the metabolites, not till extremely late loss of neurons. This circumstance explains the very torpid progress of this disease.     

Familial Lafora body disease of late onset: report of four cases in one family and a review of the literature

Lafora body disease is one cause of progressive myoclonus epilepsy. It typically presents in the second decade with generalized seizures, myoclonus and then intellectual decline. Death is usual within 10 years. Diagnosis may be made by biopsy of skin, muscle, liver or brain. We present four siblings who were normal until their mid-twenties, but then developed intellectual decline, followed by myoclonus. Although a rare form of Lafora body disease has been described that follows a more benign course, may be of later onset, and whose pathology is subtly different, this family is so far unique in terms of the late presentation of otherwise typical Lafora body disease. Received: 29 March 1996 Received in revised form: 22 July 1996 Accepted: 5 August 1996     

Inhibiting glycogen synthesis prevents lafora disease in a mouse model

Lafora disease (LD) is a fatal progressive myoclonus epilepsy characterized neuropathologically by aggregates of abnormally structured glycogen and proteins (Lafora bodies [LBs]), and neurodegeneration. Whether LBs could be prevented by inhibiting glycogen synthesis and whether they are pathogenic remain uncertain. We genetically eliminated brain glycogen synthesis in LD mice. This resulted in long‐term prevention of LB formation, neurodegeneration, and seizure susceptibility. This study establishes that glycogen synthesis is requisite for LB formation and that LBs are pathogenic. It opens a therapeutic window for potential treatments in LD with known and future small molecule inhibitors of glycogen synthesis. Ann Neurol 2013;74:297–300     

A novel codon4 mutation (A4F) in the SOD1gene in familial amyotrophic lateral sclerosis

Degos' disease or malignant atrophic papulosis is a rare disseminated occlusive vasculopathy affecting the skin, gastrointestinal tract, central nervous system, and less often other organ systems. The exact etiology of this vasculopathy has not been established. Infections, autoimmune disease and coagulation defects have been proposed as underlying pathogenic mechanisms, but none have been confirmed. Here, we report the clinical, radiological and histopathologic features of Degos' disease in a 41-year-old man following streptococcal throat infection. Prior postulated hypothesis as post-infectious immunologic mechanism may be further supported by this case.     

Lafora disease: diagnosis by liver biopsy

We have studied four patients who had a clinical course compatible with Lafora disease. The diagnosis was confirmed in one by the presence of Lafora bodies in central nervous system neurons at autopsy and was supported in another by findings in the cerebral biopsy of a sibling. Our patients had no clinically apparent liver disease, but liver specimens in each instance showed a distinctive histological abnormality, with hepatocytes containing inclusions having a ground-glass appearance. The liver biopsy findings appear to be relatively specific for this disorder and can easily be differentiated from those in other liver diseases.     

Mental deterioration in Lafora's disease

Lafora's disease is included among the progressive myoclonic epilepsies. Despite the fact that dementia is a constant finding in this disease only a few papers have studied the timing of mental deterioration. We have performed wide neuropsychological testing in two cases early diagnosed as Lafora disease. The initial neuropsychological testing was carried out by the time there were no complaints of mental deterioration in both cases. In the first case consecutive neuropsychological testing demonstrated the rapidly progressive dementia. All neuropsychological testings in these cases showed severe impairment of right parietal lobe functions. Higher cortical functions related to language and intellectual processes were best preserved in both cases. The functions related to constructional praxis, memory and abstract concepts and processes were severely impaired. Our data suggest that mental deterioration is an early manifestation in Lafora disease, even by the time normal social life is not yet disturbed. Dominant hemisphere cognitive functions have been less impaired than the non-dominant ones. How a diffuse illness such as Lafora disease can cause such an asymmetrical higher cortical function deficit is not yet clear.     

Polysaccharide accumulation in the central nervous system ofd-penicillamine-treated rats

Summary A complex polysaccharide accumulation was observed in the central nervous system (CNS) of rats treated withd-penicillamine similar to Lafora-like bodies. They have histochemical similarities comparable to bodies described in previous studies of Lafora disease. The clinical usefulness ofd-penicillamine has been limited by many side effects including renal damage. It is suggested that, in addition tod-penicillamine nephropathy, there are toxic effects of this drug on the CNS.     

Periodic electroencephalogram discharges in a case of Lafora body disease: An unusual finding

Lafora body disease (LBD) is a form of progressive myoclonic epilepsy, characterized by seizures, myoclonic jerks, cognitive decline, ataxia, and intracellular polyglucosan inclusion bodies (Lafora bodies) in the neurons, heart, skeletal muscle, liver, and sweat gland duct cells. Electroencephalogram (EEG) findings in LBD may include multiple spikes and wave discharges, photosensitivity, multifocal epileptiform discharges, and progressive slowing in background activity. Periodicity in epileptiform discharges has not been frequently depicted in LBD. We herein report an unusual case of LBD who showed generalized periodic epileptiform discharges in EEG.     

Risk factors for Alzheimer's disease]

Apolipoprotein E (apoE) is the major risk factor, besides aging, for Alzheimer's disease (AD). Many hypotheses have been proposed to explain the mechanism whereby one of the isoforms of apoE, apoE4, could cause AD. We have been conducting studies on the pathogenic roles of apoE from the viewpoint of its physiological function. We previously reported that one detrimental effect of apoE4 on neuronal viability can be induced by alteration in intracellular cholesterol metabolism. In brains of patients with AD, there is a common pathological process, called the amyloid cascade. Therefore, one of the central questions regarding the pathogenic roles of apoE in the development of AD is how apoE4 enhances deposition of amyloid b-protein (A beta). In relation to this issue, evidence is now accumulating to show that the metabolism of amyloid precursor protein (APP) and A beta can be modulated by cellular cholesterol. Our recent studies revealed that a novel A beta with a unique ability to accelerate fibril formation of soluble A beta is generated in the presence of cellular cholesterol. These lines of evidence suggest that the alteration of cholesterol metabolism in neurons due to aging and/or expression of apoE4 may be a prerequisite for the development of AD.     

Anti-GQ1b ganglioside antibody in peripheral nervous system disorders: pathophysiologic role and clinical relevance

The recent literature about autoimmune peripheral neuropathies has been dominated by the discovery of antibodies to a variety of glycosphingolipids. Gangliosides are important carbohydrate determinants for autoimmune activity, and several studies have suggested that serum antibodies against gangliosides are responsible for some forms of acute and chronic neuropathy syndromes. However, this view is disputable, and despite substantial progress in understanding the potential pathogenic effects of antiganglioside antibodies, many central issues remain unresolved across the whole pathogenic process. Miller Fisher syndrome has been classified as a variant of Guillain-Barré syndrome that comprises the clinical triad of ataxia, areflexia, and ophthalmoplegia. It has been considered the archetypal antiganglioside antibody-mediated human neuropathy because anti-GQ1b ganglioside antibody is detected in most patients with Miller Fisher syndrome, decays rapidly with clinical recovery, and is not found in normal and disease control serum samples. The only other case in which this antibody is found is in patients with related conditions, which might share the same pathogenic mechanism, such as Bickerstaff brainstem encephalitis. The strength of this close serologic-clinical association is such that measurement of anti-GQ1b antibody in suspected cases of Miller Fisher syndrome is a useful diagnostic marker for clinicians. This article reviews the occurrence, the pathophysiologic role, and the clinical background of anti-GQ1b ganglioside antibody in Miller Fisher syndrome and related disorders.     

Ontogeny of Lafora bodies and neurocytoskeleton changes in Laforin-deficient mice

Lafora disease (LD) is an autosomal recessive, always fatal progressive myoclonus epilepsy with rapid cognitive and neurologic deterioration. One of the pathological hallmarks of LD is the presence of cytoplasmic PAS+polyglucosan inclusions called Lafora bodies (LBs). Current clinical and neuropathological views consider LBs to be the cause of neurological derangement of patients. A systematic study of the ontogeny and structural features of the LBs has not been done in the past. Therefore, we undertook a detailed microscopic analysis of the neuropile of a Laforin-deficient (epm2a-/-) mouse model. Wild type and epm2a-/- mice were sacrificed at different ages and their encephalon processed for light microscopy. Luxol-fast-blue, PAS, Bielschowski techniques, as well as immunocytochemistry (TUNEL, Caspase-3, Apaf-1, Cytochrome-C and Neurofilament L antibodies) were used. Young null mice (11 days old) showed necrotic neuronal death in the absence of LBs. Both cell death and LBs showed a progressive increment in size and number with age. Type I LBs emerged at two weeks of age and were distributed in somata and neurites. Type II LBs appeared around the second month of age and always showed a complex architecture and restricted to neuronal somata. Their number was considerably less than type I LBs. Bielschowski method showed neurofibrillary degeneration and senile-like plaques. These changes were more prominent in the hippocampus and ventral pons. Neurofibrillary tangles were already present in 11 days-old experimental animals, whereas senile-like plaques appeared around the third to fourth month of life. The encephalon of null mice was not uniformly affected: Diencephalic structures were spared, whereas cerebral cortex, basal ganglia, pons, hippocampus and cerebellum were notoriously affected. This uneven distribution was present even within the same structure, i.e., hippocampal sectors. Of special relevance, was the observation of the presence of immunoreactivity to neurofilament L on the external rim of type II LBs. Perhaps, type II LB is not the end point of a metabolic abnormality. Instead, we suggest that type II LB is a highly specialized structural and functional entity that emerges as a neuronal response to major carbohydrate metabolism impairment. Early necrotic cell death, neurocytoskeleton derangement, different structural and probably functional profiles for both forms of LBs, a potential relationship between the external rim of the LB type II and the cytoskeleton and an uneven distribution of these abnormalities indicate that LD is both a complex neurodegenerative disease and a glycogen metabolism disorder. Our findings are critical for future studies on disease mechanisms and therapies for LD. Interestingly, the neurodegenerative changes observed in this LD model can also be useful for understanding the process of dementia.     

Skin biopsy in Lafora disease: genotype-phenotype correlations and diagnostic pitfalls

Lafora disease is characterized by pathognomonic inclusions, Lafora bodies (LB), in neurons and other cell types. In skin, LB have been reported in either eccrine sweat glands or in apocrine sweat glands. The disease is caused by mutations in either the EPM2A gene or in a second yet-unknown gene. Here the authors determine whether a genotype-phenotype correlation exists between the genetic form of the disease and the skin cell type affected by LB formation. Also is described an important source of false positivity in the use of axillary biopsies for disease diagnosis.     

Amyotrophic lateral sclerosis: An unconventional autoimmune disease?

The possibility of an autoimmune mechanism of pathogenesis in amyotrophic lateral sclerosis has long been considered, but the evidence to support a conventional autoimmune process, reviewed here, is inconclusive. However, antibodies that react in vitro with gangliosides have recently been found in sera of a large majority of patients with classical amyotrophic lateral sclerosis and other motor neuron syndromes. A working hypothesis is proposed, suggesting how antibodies might be related to the disease process. The hypothesis attempts to account for (1) a pathogenic role of antibodies directed against the carbohydrate components of glycolipids, (2) the selectivity of the process for motor neurons, (3) an antibody-mediated mechanism that could result in apparently degenerative neuropathological changes without signs of inflammation, and (4) a type of autoimmune response that is extremely difficult to suppress by conventional means. Although the evidence for this hypothesis is by no means complete, its critical features are all testable.     

Targeting Gys1 with AAV‐SaCas9 Decreases Pathogenic Polyglucosan Bodies and Neuroinflammation in Adult Polyglucosan Body and Lafora Disease Mouse Models

Many adult and most childhood neurological diseases have a genetic basis. CRISPR/Cas9 biotechnology holds great promise in neurological therapy, pending the clearance of major delivery, efficiency, and specificity hurdles. We applied CRISPR/Cas9 genome editing in its simplest modality, namely inducing gene sequence disruption, to one adult and one pediatric disease. Adult polyglucosan body disease is a neurodegenerative disease resembling amyotrophic lateral sclerosis. Lafora disease is a severe late childhood onset progressive myoclonus epilepsy. The pathogenic insult in both is formation in the brain of glycogen with overlong branches, which precipitates and accumulates into polyglucosan bodies that drive neuroinflammation and neurodegeneration. We packaged Staphylococcus aureus Cas9 and a guide RNA targeting the glycogen synthase gene, Gys1, responsible for brain glycogen branch elongation in AAV9 virus, which we delivered by neonatal intracerebroventricular injection to one mouse model of adult polyglucosan body disease and two mouse models of Lafora disease. This resulted, in all three models, in editing of approximately 17% of Gys1 alleles and a similar extent of reduction of Gys1 mRNA across the brain. The latter led to approximately 50% reductions of GYS1 protein, abnormal glycogen accumulation, and polyglucosan bodies, as well as ameliorations of neuroinflammatory markers in all three models. Our work represents proof of principle for virally delivered CRISPR/Cas9 neurotherapeutics in an adult-onset (adult polyglucosan body) and a childhood-onset (Lafora) neurological diseases.Supplementary InformationThe online version contains supplementary material available at 10.1007/s13311-021-01040-7.     

The maestro don Gonzalo Rodríguez-Lafora

Gonzalo Rodríguez-Lafora (1886–1971) was an influential Spanish neurologist, and has been called the last of Cajal's great Spanish disciples. Of course, he is best known now for describing (in 1911) the intracytoplasmic inclusion bodies in "Lafora disease." In total, he published ∼200 papers covering a wide range of subjects in neurology, psychiatry, and neuropathology. He made seminal contributions not only to the clinical and scientific literature but also to the training of many noted disciples who paid him due homage as a true "maestro." Throughout his intellectual endeavors, Lafora manifested a singular purpose and intensity and a burning devotion to scientific honesty.