Update on polyglucosan storage diseases

Amylopectinosis of the fatal epilepsy Lafora disease resists autophagic glycogen catabolism

In this Correspondence, B. Minassian and colleagues report that GHF201, an autophagy activator shown to diminish abnormal glycogen aggregates in a mouse model of Adult Polyglucosan Body Disease, fails to reduce such accumulations in a mouse model of Lafora disease.

Myofiber-type-dependent 'boulder' or 'multitudinous pebble' formations across distinct amylopectinoses

At least five enzymes including three E3 ubiquitin ligases are dedicated to glycogen's spherical structure. Absence of any reverts glycogen to a structure resembling amylopectin of the plant kingdom. This amylopectinosis (polyglucosan body formation) causes fatal neurological diseases including adult polyglucosan body disease (APBD) due to glycogen branching enzyme deficiency, Lafora disease (LD) due to deficiencies of the laforin glycogen phosphatase or the malin E3 ubiquitin ligase and type 1 polyglucosan body myopathy (PGBM1) due to RBCK1 E3 ubiquitin ligase deficiency. Little is known about these enzymes' functions in glycogen structuring. Toward understanding these functions, we undertake a comparative murine study of the amylopectinoses of APBD, LD and PGBM1. We discover that in skeletal muscle, polyglucosan bodies form as two main types, small and multitudinous ('pebbles') or giant and single ('boulders'), and that this is primarily determined by the myofiber types in which they form, 'pebbles' in glycolytic and 'boulders' in oxidative fibers. This pattern recapitulates what is known in the brain in LD, innumerable dust-like in astrocytes and single giant sized in neurons. We also show that oxidative myofibers are relatively protected against amylopectinosis, in part through highly increased glycogen branching enzyme expression. We present evidence of polyglucosan body size-dependent cell necrosis. We show that sex influences amylopectinosis in genotype, brain region and myofiber-type-specific fashion. RBCK1 is a component of the linear ubiquitin chain assembly complex (LUBAC), the only known cellular machinery for head-to-tail linear ubiquitination critical to numerous cellular pathways. We show that the amylopectinosis of RBCK1 deficiency is not due to loss of linear ubiquitination, and that another function of RBCK1 or LUBAC must exist and operate in the shaping of glycogen. This work opens multiple new avenues toward understanding the structural determinants of the mammalian carbohydrate reservoir critical to neurologic and neuromuscular function and disease.

Lafora Disease: A Case Report and Evolving Treatment Advancements

Lafora disease is a rare genetic disorder characterized by a disruption in glycogen metabolism. It manifests as progressive myoclonus epilepsy and cognitive decline during adolescence. Pathognomonic is the presence of abnormal glycogen aggregates that, over time, produce large inclusions (Lafora bodies) in various tissues. This study aims to describe the clinical and histopathological aspects of a novel Lafora disease patient, and to provide an update on the therapeutical advancements for this disorder. A 20-year-old Libyan boy presented with generalized tonic-clonic seizures, sporadic muscular jerks, eyelid spasms, and mental impairment. Electroencephalography showed multiple discharges across both brain hemispheres. Brain magnetic resonance imaging was unremarkable. Muscle biopsy showed increased lipid content and a very mild increase of intermyofibrillar glycogen, without the polyglucosan accumulation typically observed in Lafora bodies. Despite undergoing three lines of antiepileptic treatment, the patient's condition showed minimal to no improvement. We identified the homozygous variant c.137G>A, p.(Cys46Tyr), in the EPM2B/NHLRC1 gene, confirming the diagnosis of Lafora disease. To our knowledge, the presence of lipid aggregates without Lafora bodies is atypical. Lafora disease should be considered during the differential diagnosis of progressive, myoclonic, and refractory epilepsies in both children and young adults, especially when accompanied by cognitive decline. Although there are no effective therapies yet, the development of promising new strategies prompts the need for an early and accurate diagnosis.

Polyglucosan body disease in an aged chimpanzee (Pan troglodytes)

A 57-year-old female chimpanzee presented with a brief history of increasing lethargy and rapidly progressive lower-limb weakness that culminated in loss of use. Postmortem examination revealed no significant gross lesions in the nervous system or other organ systems. Histological analysis revealed round, basophilic to amphophilic polyglucosan bodies (PGBs) in the white and gray matter of the cervical, thoracic, lumbar, and coccygeal regions of spinal cord. Only rare PGBs were observed in forebrain samples. The lesions in the spinal cord were polymorphic, and they were positively stained with hematoxylin, periodic acid Schiff, Alcian blue, toluidine blue, Bielschowsky silver, and Grocott-Gomori methenamine-silver methods, and they were negative for von Kossa and Congo Red stains. Immunohistochemical evaluation revealed reactivity with antibodies to ubiquitin, but they were negative for glial fibrillary acidic protein, neuron-specific enolase, neurofilaments, tau protein, and Aβ protein. Electron microscopy revealed non-membrane-bound deposits composed of densely packed filaments within axons and in the extracellular space. Intra-axonal PGBs were associated with disruption of the axonal fine structure and disintegration of the surrounding myelin sheath. These findings are the first description of PGBs linked to neurological dysfunction in a chimpanzee. Clinicopathologically, the disorder resembled adult PGB disease in humans.

Inherited metabolic disorders in adults: systematic review on patient characteristics and diagnostic yield of broad sequencing techniques (exome and genome sequencing)

BACKGROUND/OBJECTIVES

The timely diagnosis of inherited metabolic disorders (IMD) is essential for initiating treatment, prognostication and genetic testing of relatives. Recognition of IMD in adults is difficult, because phenotypes are different from those in children and influenced by symptoms from acquired conditions. This systematic literature review aims to answer the following questions: (1) What is the diagnostic yield of exome/genome sequencing (ES/GS) for IMD in adults with unsolved phenotypes? (2) What characteristics do adult patients diagnosed with IMD through ES/GS have?

METHODS

A systematic search was conducted using the following search terms (simplified): "Whole exome sequencing (WES)," "Whole genome sequencing (WGS)," "IMD," "diagnostics" and the 1,450 known metabolic genes derived from ICIMD. Data from 695 articles, including 27,702 patients, were analyzed using two different methods. First, the diagnostic yield for IMD in patients presenting with a similar phenotype was calculated. Secondly, the characteristics of patients diagnosed with IMD through ES/GS in adulthood were established.

RESULTS

The diagnostic yield of ES and/or GS for adult patients presenting with unexplained neurological symptoms is 11% and for those presenting with dyslipidemia, diabetes, auditory and cardiovascular symptoms 10, 9, 8 and 7%, respectively. IMD patients diagnosed in adulthood (n = 1,426), most frequently portray neurological symptoms (65%), specifically extrapyramidal/cerebellar symptoms (57%), intellectual disability/dementia/psychiatric symptoms (41%), pyramidal tract symptoms/myelopathy (37%), peripheral neuropathy (18%), and epileptic seizures (16%). The second most frequently observed symptoms were ophthalmological (21%). In 47% of the IMD diagnosed patients, symptoms from multiple organ systems were reported. On average, adult patients are diagnosed 15 years after first presenting symptoms. Disease-related abnormalities in metabolites in plasma, urine or cerebral spinal fluid were identified in 40% of all patients whom underwent metabolic screening. In 52% the diagnosis led to identification of affected family members with the same IMD.

CONCLUSION

ES and/or GS is likely to yield an IMD diagnosis in adult patients presenting with an unexplained neurological phenotype, as well as in patients with a phenotype involving multiple organ systems. If a gene panel does not yield a conclusive diagnosis, it is worthwhile to analyze all known disease genes. Further prospective research is needed to establish the best diagnostic approach (type and sequence of metabolic and genetic test) in adult patients presenting with a wide range of symptoms, suspected of having an IMD.

SYSTEMATIC REVIEW REGISTRATION

https://www.crd.york.ac.uk/prospero/, identifier: CRD42021295156.

Metabolic Cardiomyopathies and Cardiac Defects in Inherited Disorders of Carbohydrate Metabolism: A Systematic Review

Heart failure (HF) is a progressive chronic disease that remains a primary cause of death worldwide, affecting over 64 million patients. HF can be caused by cardiomyopathies and congenital cardiac defects with monogenic etiology. The number of genes and monogenic disorders linked to development of cardiac defects is constantly growing and includes inherited metabolic disorders (IMDs). Several IMDs affecting various metabolic pathways have been reported presenting cardiomyopathies and cardiac defects. Considering the pivotal role of sugar metabolism in cardiac tissue, including energy production, nucleic acid synthesis and glycosylation, it is not surprising that an increasing number of IMDs linked to carbohydrate metabolism are described with cardiac manifestations. In this systematic review, we offer a comprehensive overview of IMDs linked to carbohydrate metabolism presenting that present with cardiomyopathies, arrhythmogenic disorders and/or structural cardiac defects. We identified 58 IMDs presenting with cardiac complications: 3 defects of sugar/sugar-linked transporters (GLUT3, GLUT10, THTR1); 2 disorders of the pentose phosphate pathway (G6PDH, TALDO); 9 diseases of glycogen metabolism (GAA, GBE1, GDE, GYG1, GYS1, LAMP2, RBCK1, PRKAG2, G6PT1); 29 congenital disorders of glycosylation (ALG3, ALG6, ALG9, ALG12, ATP6V1A, ATP6V1E1, B3GALTL, B3GAT3, COG1, COG7, DOLK, DPM3, FKRP, FKTN, GMPPB, MPDU1, NPL, PGM1, PIGA, PIGL, PIGN, PIGO, PIGT, PIGV, PMM2, POMT1, POMT2, SRD5A3, XYLT2); 15 carbohydrate-linked lysosomal storage diseases (CTSA, GBA1, GLA, GLB1, HEXB, IDUA, IDS, SGSH, NAGLU, HGSNAT, GNS, GALNS, ARSB, GUSB, ARSK). With this systematic review we aim to raise awareness about the cardiac presentations in carbohydrate-linked IMDs and draw attention to carbohydrate-linked pathogenic mechanisms that may underlie cardiac complications.

Metabolic Myopathies in the Era of Next-Generation Sequencing

Metabolic myopathies are rare inherited disorders that deserve more attention from neurologists and pediatricians. Pompe disease and McArdle disease represent some of the most common diseases in clinical practice; however, other less common diseases are now better-known. In general the pathophysiology of metabolic myopathies needs to be better understood. Thanks to the advent of next-generation sequencing (NGS), genetic testing has replaced more invasive investigations and sophisticated enzymatic assays to reach a final diagnosis in many cases. The current diagnostic algorithms for metabolic myopathies have integrated this paradigm shift and restrict invasive investigations for complicated cases. Moreover, NGS contributes to the discovery of novel genes and proteins, providing new insights into muscle metabolism and pathophysiology. More importantly, a growing number of these conditions are amenable to therapeutic approaches such as diets of different kinds, exercise training protocols, and enzyme replacement therapy or gene therapy. Prevention and management-notably of rhabdomyolysis-are key to avoiding serious and potentially life-threatening complications and improving patients' quality of life. Although not devoid of limitations, the newborn screening programs that are currently mushrooming across the globe show that early intervention in metabolic myopathies is a key factor for better therapeutic efficacy and long-term prognosis. As a whole NGS has largely increased the diagnostic yield of metabolic myopathies, but more invasive but classical investigations are still critical when the genetic diagnosis is unclear or when it comes to optimizing the follow-up and care of these muscular disorders.

[Neuropathology II: diseases of the central and peripheral nervous systems : Outlook on new techniques in electron microscopy]

In the diagnosis of diseases of the central and peripheral nervous systems, the use of electron microscopic analyses has become rare these days. However, there are questions in which the method is helpful in confirming the etiopathogenesis of the disease. Hereditary neurodegenerative and metabolic diseases, such as the lysosomal storage disease neuronal ceroid lipofuscinosis, are associated with pathognomonic storage products not only in the central nervous system (CNS) but also in extracerebral tissues such as sweat glands and lymphocytes. These tissues are easily accessible and thus function as "windows to the CNS". In addition, there are new methods that overcome limitations of conventional electron microscopy and may improve ultrastructural diagnostics. This is particularly important for the correct classification of viral particles such as SARS-CoV‑2, leading to a better understanding of COVID19-associated diseases in the CNS and peripheral nervous system.

Diagnosis and management of glycogen storage disease type IV, including adult polyglucosan body disease: A clinical practice resource

Glycogen storage disease type IV (GSD IV) is an ultra-rare autosomal recessive disorder caused by pathogenic variants in GBE1 which results in reduced or deficient glycogen branching enzyme activity. Consequently, glycogen synthesis is impaired and leads to accumulation of poorly branched glycogen known as polyglucosan. GSD IV is characterized by a remarkable degree of phenotypic heterogeneity with presentations in utero, during infancy, early childhood, adolescence, or middle to late adulthood. The clinical continuum encompasses hepatic, cardiac, muscular, and neurologic manifestations that range in severity. The adult-onset form of GSD IV, referred to as adult polyglucosan body disease (APBD), is a neurodegenerative disease characterized by neurogenic bladder, spastic paraparesis, and peripheral neuropathy. There are currently no consensus guidelines for the diagnosis and management of these patients, resulting in high rates of misdiagnosis, delayed diagnosis, and lack of standardized clinical care. To address this, a group of experts from the United States developed a set of recommendations for the diagnosis and management of all clinical phenotypes of GSD IV, including APBD, to support clinicians and caregivers who provide long-term care for individuals with GSD IV. The educational resource includes practical steps to confirm a GSD IV diagnosis and best practices for medical management, including (a) imaging of the liver, heart, skeletal muscle, brain, and spine, (b) functional and neuromusculoskeletal assessments, (c) laboratory investigations, (d) liver and heart transplantation, and (e) long-term follow-up care. Remaining knowledge gaps are detailed to emphasize areas for improvement and future research.

Distinct features in adult polyglucosan body disease: a case series

Adult polyglucosan body disease (APBD) is caused by bi-allelic pathogenic variants in GBE1 and typically shows middle age onset urinary symptoms followed by progressive gait disturbances and possibly cognitive decline. Here we present a Belgian cohort of four patients from three families showing both classical and atypical signs of APBD. By clinical phenotyping, detailed neuroimaging of both central nervous system and skeletal muscle, genetic and biochemical testing, we confront our findings with the classical presentation of adult polyglucosan body disease and emphasize the importance of a multidisciplinary approach when diagnosing these patients.

Intestinal Pathology in Patients With Pathogenic ACTG2-Variant Visceral Myopathy: 16 Patients From 12 Families and Review of the Literature

BACKGROUND

Dominant gamma-smooth muscle actin gene (ACTG2) variants cause clinically diverse forms of visceral myopathy. Many patients undergo intestinal resection or biopsy before identification of their genetic defect. The pathology of ACTG2-variant visceral myopathy has not been evaluated systematically.

METHODS

Glass slides, ultrastructural images, molecular genetic reports, and clinical records from 16 patients with pathogenic (15) or likely pathogenic (1) ACTG2 variants were reviewed and compared with surgical specimens from controls (no evidence of a primary myopathy or pseudo-obstruction due to Hirschsprung disease) and published descriptions.

RESULTS

The variable clinical manifestations in our cohort matched those in the literature. Only non-specific light and electron microscopic findings observed in non-myopathic controls were encountered in 13 of 16 patients. The remaining 3 patients harbored hyalinized cytoplasmic inclusions in smooth muscle cells and 1 of them had polyglucosan bodies in the muscularis propria.

CONCLUSIONS

Apart from hyalinized inclusions, which were only observed in 3/16 patients, intestinal pathology in the majority of patients with ACTG2 variants is not indicative of an underlying visceral myopathy. Molecular testing should be considered even when no diagnostic intestinal pathology is identified.

Pathomorphogenesis of Glycogen-Ground Glass Hepatocytic Inclusions (Polyglucosan Bodies) in Children after Liver Transplantation

Seventeen out of 764 liver biopsies from transplanted (Tx) livers in children showed glycogen-ground glass (GGG) hepatocytic inclusions. The inclusions were not present in pre-Tx or in the explanted or donor’s liver. Under the electron microscope (EM), the stored material within the cytosol appeared as non-membrane-bound aggregates of electron-lucent globoid or fibrillar granules, previously described as abnormally structured glycogen and identified as Polyglucosan bodies (PB). The appearance of GGG in our children was analogous to that of PB-GGG occurring in a number of congenital diseases due to gene mutations such as Lafora’s d., Andersen’s d., Adult Polyglucosan Body Disease and glycogenin deficiency. The same type of GGG was previously reported in the liver of patients undergoing transplants, immunosuppressive or antiblastic treatment. To explore the potential mechanism of GGG formation, we examined whether the drugs after whose treatment this phenomenon was observed could have a role. By carrying out molecular docking, we found that such drugs somehow present a high binding affinity for the active region of glycogenin, implicating that they can inactivate the protein, thus preventing its interaction with glycogen synthase (GS), as well as the maturation of the nascent glycogen towards gamma, beta or alfa glycogen granules. We could also demonstrate that PG inclusions consist of a complex of PAS positive material (glycogen) and glycogen-associated proteins, i.e., glicogenin-1 and -2 and ubiquitin. These features appear to be analogous to congenital GGG, suggesting that, in both cases, they result from the simultaneous dysregulation of glycogen synthesis and degradation. Drug-induced GGG appear to be toxic to the cell, despite their reversibility.

Utilization of Skin Biopsy for Diagnosis in a case of Lafora Disease

Lafora disease is a rare inherited neurodegenerative disease with onset in adolescence. Patients present with progressive myoclonic seizures and cognitive decline. The disease is linked to mutations in either of the two genes encoding malin and laforin, and it is associated with the accumulation of polyglucosan inclusions (Lafora bodies) in various tissues, such as brain, liver, muscle, and skin, with the skin being particularly accessible for biopsy. Histopathologic examination of affected tissue with demonstration of Lafora bodies, together with presence of pathologic mutation in EPM2A or NHLRC1 genes, is sufficient for diagnosis of this neurologic disorder when clinically suspected. Here, we report the case of a 16-year-old female with progressive neurologic symptoms and homozygous mutation in the NHLRC1 gene encoding malin. Skin biopsy was instrumental in reaching the final diagnosis by demonstrating Lafora bodies in sweat glands by histopathologic and electron microscopic examination. This article is protected by copyright. All rights reserved.

A novel variant of RBCK1 gene causes mild polyglucosan myopathy

Homozygous or compound heterozygous pathogenic variants of the RBCK1 gene can result in a systemic disorder characterized by the accumulation of complex carbohydrate molecules, namely polyglucosan bodies in the muscular tissues. The role of this gene in the pathophysiology of the disorder at the molecular level remains unclear. Being a very rare disorder, the medical knowledge is based on just a few reported cases. Here we report a 7-year-old girl who presented with exercise intolerance and hepatosplenomegaly. Her liver profile was constantly raised. The genetic investigation has revealed a variant of the RBCK1 gene of unknown significance, which has later been confirmed as pathogenic via a variety of clinical, genetic, and histopathological approaches. More importantly, it is evident that the availability of sophisticated genetic testing, such as whole-exome sequencing, has significantly improved the knowledge of and diagnosis of many rare metabolic disorders.

From corpora amylacea to wasteosomes: History and perspectives

Corpora amylacea (CA) have been described in several human organs and have been associated with ageing and several pathological conditions. Although they were first discovered two centuries ago, their function and significance have not yet been identified. Here, we provide a chronological summary of the findings on CA in various organs and identify their similarities. After collecting and integrating these findings, we propose to consider CA as waste containers created by specific cells, which sequester waste products and foreign products, and assemble them within a glycan structure. The containers are then secreted into the external medium or interstitial spaces, in this latter case subsequently being phagocytosed by macrophages. This proposal explains, among others, why CA are so varied in content, why only some of them contain fibrillary amyloid proteins, why all of them contain glycan structures, why some of them contain neo-epitopes and are phagocytosed, and why they can be intracellular or extracellular structures. Lastly, in order to avoid the ambiguity of the term amyloid (which can indicate starch-like structures but also insoluble fibrillary proteins), we propose renaming CA as "wasteosomes", emphasising the waste products they entrap rather than their misleading amyloid properties.

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.

Adult polyglucosan body disease: an acute presentation leading to unmasking of this rare disorder

Introduction: Adult polyglucosan body disease (APBD) is an autosomal recessive leukodystrophy caused by abnormal intracellular accumulation of glycogen byproducts. This disorder is linked to a deficiency in glycogen branching enzyme-1 (GBE-1). Neurologic manifestations include upper and lower motor neuron signs, dementia, and peripheral neuropathy. APBD is typically a progressive disease. In this report, we discuss a novel case of APBD in a patient who had a sudden onset of spastic quadriparesis preceded by gradual difficulty with gait. Genetic and postmortem analysis confirmed the diagnosis of APBD.Case report: A 65-year-old man was evaluated for a new-onset of spastic quadriparesis, right-gaze preference, and left-sided beat nystagmus. Magnetic resonance imaging (MRI) of the brain revealed areas of white matter hyperintensities most prominent in the brainstem and periventricular regions. MRI of the cervical spine showed marked cord atrophy. Laboratory workup and cerebrospinal fluid analysis were unremarkable. Genetic testing supported the diagnosis of APBD due to GBE-1 deficiency. Postmortem analysis showed multiple white matter abnormalities suggestive of a leukodystrophy syndrome, and histopathologic testing revealed abnormal accumulation of polyglucosan bodies in samples from the patient's central nervous system supporting the diagnosis of APBD.Conclusion: APBD is a rare disorder that can affect the nervous system. The diagnosis can be confirmed with a combination of genetic testing and pathologic analysis of affected brain tissue.

Liver Transplantation for Glycogen Storage Disease Type IV

Glycogen storage disease type IV (GSD IV) is a rare autosomal recessive disorder caused by glycogen-branching enzyme (GBE) deficiency, leading to accumulation of amylopectin-like glycogen that may damage affected tissues. The clinical manifestations of GSD IV are heterogeneous; one of which is the classic manifestation of progressive hepatic fibrosis. There is no specific treatment available for GSD IV. Currently, liver transplantation is an option. It is crucial to evaluate long-term outcomes of liver transplantation. We reviewed the published literature for GSD IV patients undergoing liver transplantation. To date, some successful liver transplantations have increased the quantity and quality of life in patients. Although the extrahepatic manifestations of GSD IV may still progress after transplantation, especially cardiomyopathy. Patients with cardiac involvement are candidates for cardiac transplantation. Liver transplantation remains the only effective therapeutic option for treatment of GSD IV. However, liver transplantation may not alter the extrahepatic progression of GSD IV. Patients should be carefully assessed before liver transplantation.

Shared and Distinctive Ultrastructural Abnormalities Expressed by Megakaryocytes in Bone Marrow and Spleen From Patients With Myelofibrosis

Numerous studies have documented ultrastructural abnormalities in malignant megakaryocytes from bone marrow (BM) of myelofibrosis patients but the morphology of these cells in spleen, an important extramedullary site in this disease, was not investigated as yet. By transmission-electron microscopy, we compared the ultrastructural features of megakaryocytes from BM and spleen of myelofibrosis patients and healthy controls. The number of megakaryocytes was markedly increased in both BM and spleen. However, while most of BM megakaryocytes are immature, those from spleen appear mature with well-developed demarcation membrane systems (DMS) and platelet territories and are surrounded by platelets. In BM megakaryocytes, paucity of DMS is associated with plasma (thick with protrusions) and nuclear (dilated with large pores) membrane abnormalities and presence of numerous glycosomes, suggesting a skewed metabolism toward insoluble polyglucosan accumulation. By contrast, the membranes of the megakaryocytes from the spleen were normal but these cells show mitochondria with reduced crests, suggesting deficient aerobic energy-metabolism. These distinctive morphological features suggest that malignant megakaryocytes from BM and spleen express distinctive metabolic impairments that may play different roles in the pathogenesis of myelofibrosis.

Adult polyglucosan body disease - Management and evolution in an intensive rehabilitation program

Adult polyglucosan body disease is a rare neuromuscular genetic disorder. It is characterized by accumulation of an abnormal structural form of glycogen, particularly in central and peripheral nervous system and muscles. Functional impairments and the rehabilitation approach of this entity is rarely reported. We present a case of a 65-year-old female with several years of undiagnosed symptoms. One year after the diagnosis, the patient was evaluated for the first time in a physical and rehabilitation consultation. We describe the inpatient rehabilitation program - an approach planned to achieve high levels of treatment intensity and with intervention of a multiprofessional and multidisciplinary team.

Metastasis of Uveal Melanoma with Monosomy-3 Is Associated with a Less Glycogenetic Gene Expression Profile and the Dysregulation of Glycogen Storage

The prolonged storage of glucose as glycogen can promote the quiescence of tumor cells, whereas the accumulation of an aberrant form of glycogen without the primer protein glycogenin can induce the metabolic switch towards a glycolytic phenotype. Here, we analyzed the expression of n = 67 genes involved in glycogen metabolism on the uveal melanoma (UM) cohort of the Cancer Genome Atlas (TCGA) study and validated the differentially expressed genes in an independent cohort. We also evaluated the glycogen levels with regard to the prognostic factors via a differential periodic acid-Schiff (PAS) staining. UMs with monosomy-3 exhibited a less glycogenetic and more insulin-resistant gene expression profile, together with the reduction of glycogen levels, which were associated with the metastases. Expression of glycogenin-1 (Locus: 3q24) was lower in the monosomy-3 tumors, whereas the complementary isoform glycogenin-2 (Locus: Xp22.33) was upregulated in females. Remarkably, glycogen was more abundant in the monosomy-3 tumors of male versus female patients. We therefore provide the first evidence to the dysregulation of glycogen metabolism as a novel factor that may be aggravating the course of UM particularly in males.