scholarly journals Canine Lafora Disease: An Unstable Repeat Expansion Disorder

Life ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 689
Author(s):  
Thilo von Klopmann ◽  
Saija Ahonen ◽  
Irene Espadas-Santiuste ◽  
Kaspar Matiasek ◽  
Daniel Sanchez-Masian ◽  
...  
Keyword(s):  
Genetic Testing ◽  
Vision Loss ◽  
Clinical Signs ◽  
Myotendinous Junction ◽  
Homozygous Mutation ◽  
Loss Of Function ◽  
Lafora Disease ◽  
Polyglucosan Bodies ◽  
Lafora Bodies ◽  
Mixed Breed

Canine Lafora disease is a recessively inherited, rapidly progressing neurodegenerative disease caused by the accumulation of abnormally constructed insoluble glycogen Lafora bodies in the brain and other tissues due to the loss of NHL repeat containing E3 ubiquitin protein ligase 1 (NHLRC1). Dogs have a dodecamer repeat sequence within the NHLRC1 gene, which is prone to unstable (dynamic) expansion and loss of function. Progressive signs of Lafora disease include hypnic jerks, reflex and spontaneous myoclonus, seizures, vision loss, ataxia and decreased cognitive function. We studied five dogs (one Chihuahua, two French Bulldogs, one Griffon Bruxellois, one mixed breed) with clinical signs associated with canine Lafora disease. Identification of polyglucosan bodies (Lafora bodies) in myocytes supported diagnosis in the French Bulldogs; muscle areas close to the myotendinous junction and the myofascial union segment had the highest yield of inclusions. Postmortem examination of one of the French Bulldogs revealed brain Lafora bodies. Genetic testing for the known canine NHLRC1 mutation confirmed the presence of a homozygous mutation associated with canine Lafora disease. Our results show that Lafora disease extends beyond previous known breeds to the French Bulldog, Griffon Bruxellois and even mixed-breed dogs, emphasizing the likely species-wide nature of this genetic problem. It also establishes these breeds as animal models for the devastating human disease. Genetic testing should be used when designing breeding strategies to determine the frequency of the NHLRC1 mutation in affected breeds. Lafora diseases should be suspected in any older dog presenting with myoclonus, hypnic jerks or photoconvulsions.

scholarly journals Targeting pathogenic Lafora bodies in Lafora disease using an antibody-enzyme fusion

2019 ◽  
Author(s):  
M. Kathryn Brewer ◽  
Annette Uittenbogaard ◽  
Grant Austin ◽  
John J. McCarthy ◽  
Dyann M. Segvich ◽  
...  
Keyword(s):  
Glycogen Synthesis ◽  
Intractable Epilepsy ◽  
Antibody Fragment ◽  
Glycogen Storage ◽  
Childhood Epilepsy ◽  
Lafora Disease ◽  
Polyglucosan Bodies ◽  
Lafora Bodies ◽  
Enzyme Fusion

AbstractLafora disease (LD) is a fatal childhood epilepsy and a non-classical glycogen storage disorder with no effective therapy or cure. LD is caused by recessive mutations in theEPM2AorEPM2Bgenes that encode the glycogen phosphatase laforin and an E3 ubiquitin ligase malin, respectively. A hallmark of LD is the intracellular accumulation of abnormal and insoluble α-linked polysaccharide deposits known as Lafora bodies (LBs) in several tissues, including most regions of the brain. In mouse models of LD, genetic reduction of glycogen synthesis eliminates LB formation and rescues the neurological phenotype. Since multiple groups have confirmed that neurodegeneration and epilepsy result from LB accumulation, a major focus in the field has shifted toward the development of therapies that reduce glycogen synthesis or target LBs for degradation with the goal of treating LD. Herein, we identify the optimal enzymes for degrading LBs, and we develop a novel therapeutic agent by fusing human pancreatic α-amylase to a cellpenetrating antibody fragment. This antibody-enzyme fusion (VAL-0417) degrades LBsin vitro, shows robust cellular uptake, and significantly reduces the LB loadin vivoinEpm2a-/- mice. VAL-0417 is a promising therapeutic for the treatment of LD and a putative precision therapy for an intractable epilepsy. Antibody-enzyme fusions represent a new class of antibody-based drugs that could be utilized to treat glycogen storage disorders and other diseases.One Sentence SummaryAn antibody-enzyme fusion delivering an amylase degrades the toxic polyglucosan bodies that cause Lafora disease, a fatal childhood epilepsy.

scholarly journals Lafora Disease: A Review of Molecular Mechanisms and Pathology

2018 ◽  
Vol 49 (06) ◽  
pp. 357-362 ◽  
Author(s):  
Brandy Verhalen ◽  
Susan Arnold ◽  
Berge Minassian
Keyword(s):  
Ubiquitin Ligase ◽  
Molecular Mechanisms ◽  
Neurodegenerative Disorder ◽  
Vegetative State ◽  
Glycogen Synthesis ◽  
Loss Of Function ◽  
Lafora Disease ◽  
Lafora Bodies ◽  
Progressive Myoclonus Epilepsy ◽  
Myoclonus Epilepsy

AbstractLafora's disease is a neurodegenerative disorder caused by recessive loss-of-function mutations in the EPM2A (laforin glycogen phosphatase) or EPM2B (malin E3 ubiquitin ligase) genes. Neuropathology is characterized by malformed precipitated glycogen aggregates termed Lafora bodies. Asymptomatic until adolescence, patients undergo first insidious then rapid progressive myoclonus epilepsy toward a vegetative state and death within a decade. Laforin and malin interact to regulate glycogen phosphorylation and chain length pattern, the latter critical to glycogen's solubility. Significant gaps remain in precise mechanistic understanding. However, demonstration that partial reduction in brain glycogen synthesis near-completely prevents the disease in its genetic animal models opens a direct present path to therapy.

scholarly journals The possibility of using skin biopsy in the diagnosis of Lafora disease

2020 ◽  
Vol 18 (4) ◽  
pp. 239-243
Author(s):  
L. S. Kraeva ◽  
S. V. Vtorushin ◽  
A. V. Kuzmina ◽  
D. V. Kozyritskaya
Keyword(s):  
Genetic Testing ◽  
Clinical Case ◽  
Disease Onset ◽  
Clinical Manifestations ◽  
Cognitive Disorders ◽  
Epileptic Seizures ◽  
Sweat Glands ◽  
Lafora Disease ◽  
Lafora Bodies ◽  
Progressive Myoclonus Epilepsy

Lafora disease is a hereditary, autosomal recessive progressive myoclonus epilepsy caused by mutations in the EPM2A (laforin) and EPM2B (malin) genes, with no substantial genotype-phenotype differences between the two. Clinical manifestations of the disease are determined by the accumulation of specific cytoplasmic “amyloid inclusions” consisting of polyglycosans (an abnormally branched glycogen molecule). Polyglycosans, or Lafora bodies, are typically found in the brain, hepatocytes of the liver, skeletal and cardiac muscles, in the ducts of sweat glands, and in the skin. The diagnosis is made following visual, generalized tonic-clonic and myoclonic seizures, progressing dementia, cerebellar ataxia, detection of specific Lafora bodies during sweat gland biopsy and data of genetic testing.The article describes a clinical case of Lafora disease in a patient with disease onset at 11 years old caused by the mutation in the EPM2A (laforine) gene with focal sensory visual seizures with subsequent generalized tonic-clonic seizures, progressive motor impairments in the form of ataxia and gait abnormality as well as behavioral and cognitive disorders. The presented clinical case demonstrates the need for additional research, such as biopsy and genetic testing, for diagnosing diseases proceeding with resistant epileptic seizures and progressive motor and cognitive impairments. 

scholarly journals A Mild Phenotype Caused by Two Novel Compound Heterozygous Mutations in CEP290

Genes ◽  
2020 ◽  
Vol 11 (11) ◽  
pp. 1240
Author(s):  
Agnieszka Rafalska ◽  
Anna M. Tracewska ◽  
Anna Turno-Kręcicka ◽  
Milena J. Szafraniec ◽  
Marta Misiuk-Hojło
Keyword(s):  
Vision Loss ◽  
Compound Heterozygous ◽  
Loss Of Function ◽  
Mild Phenotype ◽  
Cone Function ◽  
Retinal Disorders ◽  
Molecular Inversion Probes ◽  
Disease Experience ◽  
The Individual ◽  
Inherited Retinal Disorders

CEP290 is a ciliary gene frequently mutated in ciliopathies, resulting in a broad range of phenotypes, ranging from isolated inherited retinal disorders (IRDs) to severe or lethal syndromes with multisystemic involvement. Patients with non-syndromic CEP290-linked disease experience profound and early vision loss due to cone-rod dystrophy, as in Leber congenital amaurosis. In this case report, we describe two novel loss-of-function heterozygous alterations in the CEP290 gene, discovered in a patient suffering from retinitis pigmentosa using massive parallel sequencing of a molecular inversion probes library constructed for 108 genes involved in IRDs. A milder phenotype than expected was found in the individual, which serves to prove that some CEP290-associated disorders may display preserved cone function.

scholarly journals Frontal Hypoperfusion and the Effectiveness of Perampanel in Long-Lived Patient with Lafora Disease

2021 ◽  
pp. 211-217
Author(s):  
Koji Obara ◽  
Erika Abe ◽  
Itaru Toyoshima
Keyword(s):  
Single Photon ◽  
Early Stage ◽  
Photon Emission ◽  
Cerebellar Atrophy ◽  
Brain Magnetic Resonance Imaging ◽  
Emission Computed Tomography ◽  
Homozygous Mutation ◽  
Lafora Disease ◽  
Mental Deterioration ◽  
Exon 1

We report a long-lived patient with Lafora disease (LD). A 34-year-old woman experienced onset of seizures at the age of 11 years. She was bedridden in her early twenties due to frequent generalized tonic-clonic seizures, myoclonus, and progressive mental deterioration. Her seizures occurred all the time despite administration of multiple anticonvulsants at high doses. At the age of 31, she started perampanel, which resulted in reduction of anticonvulsants after her visible myoclonus and convulsions disappeared. Brain magnetic resonance imaging showed marked cerebral and cerebellar atrophy, and single-photon emission computed tomography using N-isopropyl-p-[123I] iodoamphetamine (IMP-SPECT) revealed significant hypoperfusion of the frontal lobe and cerebellum. We identified a W219R homozygous mutation in exon 1 of the NHLRC1 gene. Because perampanel may not only control seizures but also prevent mental deterioration in LD, we propose that perampanel should be administered from the early stage of LD.

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

2021 ◽  
Author(s):  
Emrah Gumusgoz ◽  
Dikran R Guisso ◽  
Sahba Kasiri ◽  
Jun Wu ◽  
Matthew Dear ◽  
...  
Keyword(s):  
Mouse Models ◽  
Lafora Disease ◽  
Polyglucosan Bodies ◽  
Polyglucosan Body

scholarly journals LC-MS/MS for Identifying Patients with CYP24A1 Mutations

2016 ◽  
Vol 62 (1) ◽  
pp. 236-242 ◽  
Author(s):  
Hemamalini Ketha ◽  
Rajiv Kumar ◽  
Ravinder J Singh
Keyword(s):  
Genetic Testing ◽  
Solid Phase ◽  
Internal Standard ◽  
Measurement Range ◽  
High Ratio ◽  
Unknown Etiology ◽  
Loss Of Function ◽  
Serum Samples ◽  
Dihydroxyvitamin D ◽  
Cytochrome P450 Family

Abstract BACKGROUND Patients have been described with loss-of-function CYP24A1 (cytochrome P450, family 24, subfamily A, polypeptide 1) mutations that cause a high ratio of 25-hydroxyvitamin D to 24,25-dihydroxyvitamin D [25(OH)D/24,25(OH)2D], increased serum 1,25-dihydroxyvitamin D, and resulting hypercalcemia, hypercalciuria and nephrolithiasis. A 25(OH)D/24,25(OH)2D ratio that can identify patients who are candidates for confirmatory CYP24A1 genetic testing would be valuable. We validated an LC-MS/MS assay for 24,25(OH)2D (D3 and D2) and determined a 25(OH)D/24,25(OH)2D cutoff to identify candidates for confirmatory genetic testing. METHODS After addition of isotope-labeled internal standard, serum samples were extracted by solid-phase extraction, derivatized with 4-phenyl-1,2,4,-triazoline-3,5-dione, and quantified by LC-MS/MS. We measured 25(OH)D/24,25(OH)2D in 91 healthy patients and 34 patients with clinically suspected CYP24A1-mediated hypercalcemia. RESULTS The limits of detection and quantification were 0.03 (0.2) and 0.1 (0.24) nmol/L, respectively, for 24,25(OH)2D3, and 0.1 (0.23) and 0.5 (1.16) nmol/L for 24,25(OH)2D2. Intra- and interassay imprecision was 4%–15% across the analytical measurement range of 0.1–25 ng/mL (0.2–60 nmol/L). No interference was observed with 25(OH)D and 1,25(OH)2D. 25(OH)D/24,25(OH)2D of 7–35 was observed in healthy patients, whereas in 2 patients with CYP24A1 mutations, 25(OH)D/24,25(OH)2D was significantly increased (99–467; P < 0.001). A 25(OH)D/24,25(OH)2D ratio ≥99 identified patients who were candidates for CYP24A1 genetic testing. CONCLUSIONS Increased 25(OH)D/24,25(OH)2D supports the diagnosis of reduced CYP24A1 activity due to mutations in CYP24A1. Measurement of 25(OH)D/24,25(OH)2D should be considered a part of the clinical workup in patients with hypercalcemia of otherwise unknown etiology.

STUDY OF CLINICAL CASES OF MYOCHE’S MYOPATHY AND DIFFERENTIAL DIAGNOSIS WITH OTHER TYPES OF ADVERSE MYOPATHIES

2021 ◽  
Author(s):  
K. Sarazhyna ◽  
Y. Solodovnikova ◽  
A. Son
Keyword(s):  
Case Report ◽  
Genetic Testing ◽  
Skeletal Muscles ◽  
Molecular Genetic ◽  
Clinical Signs ◽  
Lower Limbs ◽  
Molecular Genetic Testing ◽  
Membrane Repair ◽  
Rare Type ◽  
A Cell

Markesbery-Griggs myopathy, Miyoshi type (MM) is a rare type of myopathy, a form muscular dystrophy with the main involvement of the lower girdle and distal parts of the legs. Due to complexity of genetic testing, the diagnosis is mainly made on the neurological examination of the patient, which adds value to this case report. The childhood or adolescence onset of the disease is characterized initially by the calf muscles` wasting, accompanied by the severe elevation of the serum creatine kinase, as well as a slowly progressive ascending course. The disease refers to dysferlinopathies with various mutations in the DYSF gene. The dysferlin protein is localized in the plasma membrane and in the T-tubule system of skeletal muscles. Physiologically, skeletal muscles are constantly exposed to micromembrane lesions. Depending on the severity, these damages are restored using various complexes. One of the main reparative complexes is the dysferlin-dependent mechanism. Mutations can lead to a defect in the membrane repair, causing the influx of Ca 2+ into the cell, which leads to a cell`s destruction. There are three genetically identifiable types of Miyoshi myopathy: MMD1, MMD2, MMD3. The main clinical signs of the disease are the muscle weakness and atrophy, with predominant involvement of the distal parts of the lower limbs, especially in the gastrocnemius and plantar muscles. The MM causes tip toe walking disturbances and difficulties in climbing the stairs. Progression of the disease and further atrophy leads to the wasting of the lower girdle muscles, mainly gluteal ones. Peculiarity of these myopathies is the absence of cardiomyopathy, due to the immunity of cardiomyocytes to a deficiency of the protein dysferelin. Diagnosis is made on the basis of muscle biopsy and molecular genetic testing. The gold standard is immunoblotting or immunohistochemistry. One of treatment methods is the use of improperly folded dysferlin (treatment with a proteasome inhibitor MG-132) in fibroblasts with restoration of membrane sealing. The aim of this case report is to present an example of a possible clinical diagnosis of MM in a young man, in the absence of opportunities for molecular genetic testing.

scholarly journals Clinical Implications of the Genetic Architecture of Dilated Cardiomyopathy

2020 ◽  
Vol 22 (12) ◽  
Author(s):  
Lisa D. Wilsbacher
Keyword(s):  
Genetic Testing ◽  
Dilated Cardiomyopathy ◽  
Ventricular Arrhythmias ◽  
Genetic Architecture ◽  
Genetic Diagnosis ◽  
Clinical Approach ◽  
Loss Of Function ◽  
Increase Risk ◽  
Life Threatening ◽  
New Evidence

Abstract Purpose of Review Dilated cardiomyopathy (DCM) frequently involves an underlying genetic etiology, but the clinical approach for genetic diagnosis and application of results in clinical practice can be complex. Recent Findings International sequence databases described the landscape of genetic variability across populations, which informed guidelines for the interpretation of DCM gene variants. New evidence indicates that loss-of-function mutations in filamin C (FLNC) contribute to DCM and portend high risk of ventricular arrhythmia. Summary A clinical framework aids in referring patients for DCM genetic testing and applying results to patient care. Results of genetic testing can change medical management, particularly in a subset of genes that increase risk for life-threatening ventricular arrhythmias, and can influence decisions for defibrillator therapy. Clinical screening and cascade genetic testing of family members should be diligently pursued to identify those at risk of developing DCM.

scholarly journals Ischemic myelopathy caused by fibrocartilaginous embolism in a horse

2018 ◽  
Vol 48 (2) ◽  
Author(s):  
Welden Panziera ◽  
Ronaldo Michel Bianchi ◽  
Paula Reis Pereira ◽  
Mariana Martins Flores ◽  
Monique Togni ◽  
...  
Keyword(s):  
Cross Sections ◽  
Clinical Course ◽  
Clinical Signs ◽  
Histological Findings ◽  
Hind Limbs ◽  
Fibrocartilaginous Embolism ◽  
Mixed Breed ◽  
Liquefactive Necrosis ◽  
Gross Lesions ◽  
Multiple Blood

ABSTRACT: This report described clinical, epidemiological, and pathological aspects of ischemic myelopathy caused by fibrocartilaginous embolism (FCE) in a 10-year-old, mixed breed gelding. Clinically, the horse presented acute hind limbs paralysis, with a clinical course of approximately 24 hours. At necropsy, no gross lesions were observed. Cross-sections of the spinal cord revealed focally extensive areas of malacia from the T10 to L4 segments. Focally extensive areas of liquefactive necrosis involving the gray matter and adjacent white matter were observed on histologic sections. The lumen of multiple blood vessels in the periphery of the necrotic areas was occluded by fibrocartilaginous emboli that strongly stained with alcian blue. Clinical signs, gross necropsy, and histological findings observed in this case were identical to those described in the literature for ischemic myelopathy caused by FCE in the horse and other species.

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