Progressive Myoclonus Epilepsy Research Articles

Add-on perampanel in Lance-Adams syndrome.

Perampanel (PER) is the first-in-class selective, noncompetitive α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor antagonist that has been licensed and marketed as antiepileptic drug (AED) indicated for patients with partial-onset and primary generalized tonic–clonic seizures. A positive effect was reported in some patients with epileptic myoclonic jerks in idiopathic generalized epilepsy and in progressive myoclonic epilepsy.We treated a male patient with posthypoxic nonepileptic myoclonus (Lance–Adams syndrome) with add-on PER and achieved an almost complete cessation of jerks. This effect was reproducible and, therefore, we suggest that it might be worth trying PER in comparable cases.

Need for interprofessional collaborative practice: Lafora disease

A 19-year adolescent presented to a specialist hospital with a 5-year history of Lafora disease (LD) or progressive myoclonic epilepsy. LD (EPM2) resulting from a homozygous missense mutation in EPM2B (NHLRC1) was confirmed. Symptomatic management was done using conventional anti- epileptics and anti-myoclonics. Understanding the nature of prenatal screening and genetic alliance are an important for advocating genetic testing and genetic counseling. This framework is necessary for a transdisciplinary, preventive genetic services, and likely gene therapy.

EPILEPSY IN INBORN ERRORS OF METABOLISM

Epilepsy is a frequent and sometimes leading symptom in inborn errors of metabolism, especially in neonatal or infantile ones. Early myoclonic encephalopathy and myoclonus as a seizure type are the prototypes of epilepsy in inherited metabolic diseases. But clinical presentation also includes refractory neonatal seizures, Ohtahara syndrome, infantile spasms and progressive myoclonic epilepsy. Clinical manifestations seems to be similar in different etiology and in majority of cases look like unspecific epileptic encephalopathy. Selected treatable inborn errors of metabolism are discussed alongside with diagnostic approach to inherited metabolic epilepsies. Probably it’s better to avoid the treatment with valproic acid in clinical situations when etiology is unclear. Alternative use of levetiracetam is recommended. Besides the antiepileptic drugs we can also make pyridoxine, pyridoxal-5-phosphate and folinic acid consequent trials for 3-5 days before our diagnostic quest succeed.

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.

Striatal glucose hypometabolism in preadolescent-onset dentatorubral–pallidoluysian atrophy

Dentatorubral–pallidoluysian atrophy (DRPLA) is hereditary spinocerebellar degeneration presenting various symptoms in association with expansion of the CAG repeat in Atrophin-1 gene. The functional neuroimaging of DRPLA has been poorly investigated. The purpose of this study was to examine 18F-fluorodeoxyglucose-positron emission tomography (18F-FDG-PET) findings of DRPLA. We retrospectively investigated the cases of 14 consecutive genetically confirmed DRPLA patients at our institute. Four juvenile-onset patients underwent 18F-FDG-PET because of intractable seizures. Their 18F-FDG-PET images, clinical profiles and MRI findings were evaluated. For quantitative comparison, 3 healthy volunteers also underwent 18F-FDG-PET as controls. All four patients presented progressive myoclonus epilepsy without MRI abnormalities. Both the visual and quantitative assessments of their 18F-FDG-PET findings demonstrated bistriatal hypometabolism in only the two preadolescent-onset patients with larger CAG repeat size, whereas the two other later-onset patients showed no hypometabolism in the striatum. Bistriatal glucose hypometabolism in preadolescent-onset DRPLA patients might reflect more severe degeneration. This finding could contribute to a better understanding of DRPLA.

Impaired osteoclast homeostasis in the cystatin B-deficient mouse model of progressive myoclonus epilepsy

Progressive myoclonus epilepsy of Unverricht–Lundborg type (EPM1) is an autosomal recessively inherited disorder characterized by incapacitating stimulus-sensitive myoclonus and tonic-clonic epileptic seizures with onset at the age of 6 to 16years. EPM1 patients also exhibit a range of skeletal changes, e.g., thickened frontal cranial bone, arachnodactyly and scoliosis. Mutations in the gene encoding cystatin B (CSTB) underlie EPM1. CSTB is an inhibitor of cysteine cathepsins, including cathepsin K, a key enzyme in bone resorption by osteoclasts. CSTB has previously been shown to protect osteoclasts from experimentally induced apoptosis and to modulate bone resorption in vitro. Nevertheless, its physiological function in bone and the cause of the bone changes in patients remain unknown. Here we used the CSTB-deficient mouse (Cstb−/−) model of EPM1 to evaluate the contribution of defective CSTB protein function on bone pathology and osteoclast differentiation and function. Micro-computed tomography of hind limbs revealed thicker trabeculae and elevated bone mineral density in the trabecular bone of Cstb−/− mice. Histology from Cstb−/− mouse bones showed lower osteoclast count and thinner growth plates in long bones. Bone marrow-derived osteoclast cultures revealed lower osteoclast number and size in the Cstb−/− group. Cstb−/− osteoclasts formed less and smaller resorption pits in an in vitro assay. This impaired resorptive capacity was likely due to a decrease in osteoclast numbers and size. These data imply that the skeletal changes in Cstb−/− mice and in EPM1 patients are a result of CSTB deficiency leading to impaired osteoclast formation and consequently compromised resorptive capacity. These results suggest that the role of CSTB in osteoclast homeostasis and modulation of bone metabolism extends beyond cathepsin K regulation.

Mystery Case: Lafora periodic acid–Schiff inclusion bodies

A 16-year-old boy presented with a 5-year history of progressive cognitive decline and behavioral change followed by generalized tonic-clonic and myoclonic seizures refractory to many anticonvulsants (valproic acid, phenobarbital, clonazepam, and topiramate) and cerebellar ataxia a year later. The son of consanguineous parents, he had a family history of 2 cousins who both had epilepsy and died at the ages of 15 and 25 years. Laboratory screening tests, including lactic acid, fundus examination, brain neuroimaging, and CSF, were normal. Skin biopsy (figure) revealed periodic acid–Schiff-positive intracellular polyglucosan inclusion bodies in myoepithelial and sweat gland duct cells. These findings are typical of Lafora disease, a fatal autosomal recessive disorder caused by mutations in one of 2 known genes, both located at chromosome 6: EPM2A , which encodes the protein laforin, and EPM2B , which encodes the protein malin. Differential diagnosis must be made with other causes of progressive myoclonic epilepsies, most commonly Unverricht-Lundborg disease (Baltic myoclonus), myoclonus epilepsy and ragged-red fibers syndrome, neuronal ceroid lipofuscinosis, and type 1 sialidosis. There is no treatment, and therapy is mainly supportive and symptomatic.1,2

Ataxia and progressive myoclonic epilepsy associated with reduced ceramide synthase 1 (CERS1)

Ataxia and progressive myoclonic epilepsy associated with reduced ceramide synthase 1 (CERS1)

Acid ceramidase deficiency associated with spinal muscular atrophy with progressive myoclonic epilepsy

Spinal muscular atrophy with progressive myoclonic epilepsy (SMA-PME) is an extremely rare disorder related to the lysosomal storage disease, Farber lipogranulomatosis. Both disorders are autosomal recessive conditions caused by mutations in the ASAH1 gene encoding acid ceramidase. Farber disease is associated with joint deformities, lipomatous skin nodules, and often is fatal by 2–3 years of age; while SMA-PME is characterized by childhood-onset motor neuron disease and progressive myoclonic epilepsy. We report a case of SMA-PME with a novel mutation in the ASAH1 gene encoding acid ceramidase. The proband presented with childhood-onset of diffuse muscle atrophy and hypotonia. He also had diffuse weakness with greater proximal than distal involvement. Tongue fasciculations were present and his reflexes were either diminished or absent. He ambulated with an unsteady and hesitant gait. He subsequently developed myoclonic epilepsy along with other associated features including tremor, polymyoclonus, and sensorineural hearing loss. Neurophysiological studies revealed a motor neuron disorder and generalized epilepsy. Exome sequencing analysis identified compound heterozygous variants and biochemical analysis indicated acid ceramidase activity was approximately 12 percent of normal controls. Our proband was phenotypically similar to other cases of SMA-PME, albeit with somewhat lesser severity, slower progression, and greater longevity. As lysosomal disorders are sometimes amendable to early interventions, it is important to make early diagnoses in these cases. The combination of motor neuron disease and progressive myoclonic epilepsy should prompt genetic evaluation of ASAH1.

GSTA1, GSTM1, GSTP1 and GSTT1 polymorphisms in progressive myoclonus epilepsy: A Serbian case–control study

PurposeOxidative stress is recognized as an important factor in progressive myoclonus epilepsy (PME). Genetic polymorphism of glutathione S-transferases (GSTs), which are involved in both protection from oxidative damage and detoxification, might alter the capacity for protecting tissues from exogenous and endogenous oxidants. We aimed to assess a possible association between GST polymorphism and PME, as well as, correlation between GST genotypes and oxidative phenotype in PME patients. MethodsGSTA1, GSTM1, GSTP1 and GSTT1 genotypes were determined in 26 patients with PME and 66 controls. Byproducts of protein oxidative damage (thiol groups (P-SH) and nitrotyrosine), superoxide dismutase (SOD) and glutathione peroxidase (GPX) activities were determined. ResultsThe frequency of GSTA1, GSTM1 and GSTP1 genotypes was not significantly different between PME patients and controls, while individuals with GSTT1-null genotype were at 5.44-fold higher risk of PME than carriers of GSTT1-active genotype. Moreover, significant risk of PME was obtained in carriers of both GSTT1-null and GSTM1-null genotypes. Carriers of combined GSTA1- active and GSTT1-null genotype were at highest, 7.55-fold increased risk of PME. Byproducts of protein damage did not reach statistical significance, while SOD and GPX activities were significantly higher in PME patients then in controls. When stratified according to GST genotype, P-SH groups were significantly lower only in patients with GSTT1-null genotype in comparison to carriers of active genotype. Only SOD activity was increased in GSTT1-null when compared to corresponding active genotype. ConclusionsGSTT1-null genotype might be associated with the increased risk and enhanced susceptibility to oxidative stress in PME patients.

Progressive Myoclonus Epilepsy with Adolescent Onset: Clinical Features and Diagnosis

Many of the progressive epilepsy syndromes with adolescent onset are classified as progressive myoclonus epilepsies. It is a heterogenous group of epilepsy syndromes associated with seizure, myoclonus, and progressive neurologic decline. This review focuses on the different adolescent-onset progressive myoclonus epilepsies including Unverricht–Lundborg disease, Lafora disease, juvenile-onset neuronal ceroid lipofuscinosis, sialidosis (cherry-red spot myoclonus), dentatorubral–pallidoluysian atrophy, and myoclonic epilepsy and ragged-red fibers. Their clinical presentations, neurophysiologic and neuroimaging findings, genetics, pathology, and diagnosis are discussed.

A study of SSPE: early clinical features

Thirty two patients with subacute sclerosing panencephalitis (SSPE) admitted under the care of Department of Neurology at JJ Hospital and Grant Medical College, Mumbai during the period 1998-2003 were analyzed. All patients were evaluated clinically, with relevant investigations and neuroimaging wherever possible. Particular attention was given to early clinical features. Diagnosis was confirmed by cerebrospinal fluid study for measles antibody and by electroencephalography. The mean age of our patients was 13.4 years and the vaccinated patients tended to be older. Nine patients had received measles vaccination. Twelve percent of patients were older than the age of 20 years at the onset of symptoms. Approximately 40.6% of patients presented with symptoms of loss of vision, seizures and behavioral change. At this stage myoclonus and cognitive decline were conspicuous by their absence. Eventually typical features like myoclonus and cognitive decline evolved after a mean period of 8 months. Even in the present era, SSPE continues to remain the most important cause of progressive myoclonic epilepsy. With progressive increase in age of presentation, in patients with features like loss of vision, seizures and behavioral changes, SSPE should be carefully considered. (J Pediatr Neurol 2004; 2(2): 73–77).

Electroclinical spectrum of the neuronal ceroid lipofuscinoses associated with CLN6 mutations.

To describe the clinical and neurophysiologic patterns of patients with neuronal ceroid lipofuscinoses associated with CLN6 mutations. We reviewed the features of 11 patients with different ages at onset. Clinical disease onset occurred within the first decade of life in 8 patients and in the second and third decades in 3. All children presented with progressive cognitive regression associated with ataxia and pyramidal and extrapyramidal signs. Recurrent seizures, visual loss, and myoclonus were mostly reported after a delay from onset; 7 children were chairbound and had severe dementia less than 4 years from onset. One child, with onset at 8 years, had a milder course. Three patients with a teenage/adult onset presented with a classic progressive myoclonic epilepsy phenotype that was preceded by learning disability in one. The EEG background was slow close to disease onset in 7 children, and later showed severe attenuation; a photoparoxysmal response (PPR) was present in all. The 3 teenage/adult patients had normal EEG background and an intense PPR. Early attenuation of the electroretinogram was seen only in children with onset younger than 5.5 years. Somatosensory evoked potentials were extremely enlarged in all patients. In all patients, multifocal myoclonic jerks and seizures were a key feature, but myoclonic seizures were an early and prominent sign in the teenage/adult form only. Conversely, the childhood-onset form was characterized by initial and severe cognitive impairment coupled with electroretinogram and EEG attenuation. Cortical hyperexcitability, shown by the PPR and enlarged somatosensory evoked potentials, was a universal feature.

Expanding the Phenotype and Genetic Defects Associated with the GOSR2 Gene.

The homozygous missense mutation c.430G>T (p.G144W) in the GOSR2 gene has been repeatedly shown to cause progressive myoclonus epilepsy/ataxia. Thus far, no other disease associated GOSR2 mutation has been reported. From epilepsy, movement disorder and genetic clinics 43 patients suffering from progressive myoclonus epilepsy/ataxia were screened for defects in GOSR2, SCARB2 and CSTB. A 61-year-old female patient suffering from progressive myoclonus epilepsy was found to be compound heterozygous for the known c.430G>T and a novel c.491_493delAGA (p.K164del) GOSR2 mutation. This is so far the oldest GOSR2 patient and her disease course seems overall milder. This finding further highlights the GOSR2 gene as a cause of progressive myoclonus epilepsy and expands the genotype for a potentially weaker disease allele.

Progressive Myoclonus Epilepsies.

The progressive myoclonus epilepsies (PMEs) comprise a group of rare and heterogeneous disorders defined by the combination of action myoclonus, epileptic seizures, and progressive neurologic deterioration. Neurologic deterioration may include progressive cognitive decline, ataxia, neuropathy, and myopathy. The gene defects for the most common forms of PME (Unverricht-Lundborg disease, Lafora disease, several forms of neuronal ceroid lipofuscinoses, myoclonus epilepsy with ragged-red fibers [MERRF], and type 1 and 2 sialidoses) have been identified. The prognosis of a PME depends on the specific disease. Lafora disease, the neuronal ceroid lipofuscinoses, and the neuronopathic form of Gaucher disease have an invariably fatal course. In contrast, Unverricht-Lundborg disease has a much slower progression, and with adequate care many patients have a normal life span. The specific diseases that cause PME are diagnosed by recognition of their age of onset, the associated clinical symptoms, the clinical course, the pattern of inheritance, and by special investigations such as enzyme measurement, skin/muscle biopsy, or gene testing.

Mutation of the nuclear lamin gene LMNB2 in progressive myoclonus epilepsy with early ataxia.

We studied a consanguineous Palestinian Arab family segregating an autosomal recessive progressive myoclonus epilepsy (PME) with early ataxia. PME is a rare, often fatal syndrome, initially responsive to antiepileptic drugs which over time becomes refractory and can be associated with cognitive decline. Linkage analysis was performed and the disease locus narrowed to chromosome 19p13.3. Fourteen candidate genes were screened by conventional Sanger sequencing and in one, LMNB2, a novel homozygous missense mutation was identified that segregated with the PME in the family. Whole exome sequencing excluded other likely pathogenic coding variants in the linked interval. The p.His157Tyr mutation is located in an evolutionarily highly conserved region of the alpha-helical rod of the lamin B2 protein. In vitro assembly analysis of mutant lamin B2 protein revealed a distinct defect in the assembly of the highly ordered fibrous arrays typically formed by wild-type lamin B2. Our data suggests that disruption of the organisation of the nuclear lamina in neurons, perhaps through abnormal neuronal migration, causes the epilepsy and early ataxia syndrome and extends the aetiology of PMEs to include dysfunction in nuclear lamin proteins.

Myoclonic occipital photosensitive epilepsy with dystonia (MOPED): A familial epilepsy syndrome

To describe clinical and EEG phenotypes of a family with an unusual familial epilepsy syndrome characterized by myoclonus and dystonia. Family members underwent electroclinical phenotyping including review of EEGs and MRI. DNA from family members was genotyped using Illumina OmniExpress genotyping arrays. Parametric and nonparametric linkage analyses were performed using MERLIN. The disorder followed autosomal dominant (AD) inheritance and affected seven individuals over two generations. Seizures began at a mean of 14.5 years. Six individuals had spontaneous myoclonic seizures, of which five also had photic-induced myoclonus and four had photic-induced occipital seizures. Six individuals had convulsive seizures; generalized in two and focal in four. Photosensitivity was prominent with generalized spike wave and polyspike wave in four individuals of which two also had occipital spikes. MRI scans were normal in the four individuals tested. Extensive metabolic investigation was normal. Juvenile myoclonic epilepsy (JME) occurred in two; and JME overlapping with idiopathic photosensitive epilepsy (IPOE) in four individuals. All three affected males had a more severe disorder than the four affected females. Two males had a progressive neurological disorder with progressive myoclonus epilepsy and deterioration in their early 30s. They developed episodes of paroxysmal cervical dystonia with cognitive decline during periods of poor seizure control. One plateaued after years of poor seizure control but remained intractable with periods of deterioration. The other deteriorated with episodes of status dystonicus and status epilepticus, ataxia and a progressive ophthalmoplegia before succumbing at 38 years. Parametric linkage analysis identified three peaks achieving a maximum LOD score of 1.21. Nonparametric analysis identified eight peaks achieving LOD scores above 0.80. These were not statistically significant. This is a novel autosomal dominant familial epilepsy syndrome. "Myoclonic occipital photosensitive epilepsy with dystonia" (MOPED) involves a spectrum of phenotypes from JME, sometimes with an IPOE overlap, to progressive myoclonus epilepsy with paroxysmal dystonia.

PP01.12 – 2602: Differential diagnosis of progressive myoclonic epilepsia: Five patients with Lafora disease

Objective Lafora disease (LD) is a rare, fatal, autosomal recessive hereditary disease characterized by epilepsy, myoclonus and progressive neurological deterioration. Diagnosis is made by polyglucosan inclusion bodies (Lafora bodies) shown in skin biopsy. Responsible mutations involves either the EPM2A or NHLRC1 (EPM2B) gene. Methods We report genetic mutations and clinical courses of Lafora disease in 5 adolescents with homozygote NHLRC1 mutation and homozygous EPM2A mutation. Results A total 5 patients (3 female, 2 male) were presented with progressive myoclonic epilepsy. In all cases there were no problems at birth, childhood, and their psychomotor development were normal and attended regular school. In general seizures began around at 13–14 years old. Over the time they demostrated ataxia, and significant deterioration occurred in mental functions, myoclonus of the extremities started, and 3 of all patients were unable to walk unassisted and one of them died at 15 years old. Axillary skin biopsies were performed to all and Lafora bodies in cytoplasm were demostrated. All patients parents are second-degree relatives. Routine blood test, cerebrospinal fluid analaysis were normal. In three patients cranial magnetic resonance imaging (MRI) were normal, but 2 patients had mild serebral and serebellar atrophy. There were multifocal, from time-to-time generalized spike-wave activity were observed in their electroencephalography (EEG). Genetic analaysis for Lafora was studied and 2 patients (sublings) had same mutation) homozygous (c.336 C>A) p.Y112X mutation in EPM2A gene, homozygous (c.199 G>T) p. E67X mutation (2 patient had same mutation) in NHLRC1 gene, homozygous L 180V (CTG>GTC) mutation in EPM2A gene were detected. Conclusion LD is characterized by progressive myoclonic epilepsy and neurodegenerative symptoms. Therefore early recognation is diffucult. If patient show progressive myoclonic seizures with progressive mental deterotation, as well as ataxi we should consider LD

PP03.7 – 2754: KCTD7 mutation causing infantile neuronal ceroid lipofucinosis

Objective Neuronal ceroid lipofuscinosis (NCL) is one of the progressive myoclonic epilepsies (PME) of childhood with 14 types currently described. We present a case of NCL with a novel potassium channel tetramerization containing 7 (KCTD7) gene mutations. Case A 10 year old previously well boy presented at 23 months old with rapid onset global regression. Within 6 months he was non-ambulant and had developed generalised dystonia, non-epileptic myoclonus and epilepsy (tonic clonic seizures). Family history was unremarkable. The EEG at 29 months demonstrated a diffuse slow background and frequent independent spike and sharp waves bilaterally. MRI brain (with spectroscopy) was initially normal but at 5 and 7 years showed signal changes in both cerebellar hemispheres with mild global atrophy. Extensive neurometabolic investigations were normal including ultrastructural examination of lymphocytes, white cells and cultured fibroblasts lysosomal enzyme activity, muscle histology and respiratory chain enzymes, electroretinogram and visual evoked potentials were normal. Brain biopsy at 8 years demonstrated membrane-bound lysosomal accumulation of electron dense material in numerous neurons but did not contain curvilinear inclusion material characteristic of NCL. Repeat ultrastructural examination of lymphocytes and white cell enzyme activity was again normal. Results Genetic testing by next-generation sequencing, through DDD study, revealed autosomal recessive compound heterozygote mutations in KCTD7 gene exon 2 (c.190A>G, p. Thr64Ala) and 4 (c.631C>T, p.Arg211X). This was confirmed by DNA sequence analysis. The KCTD7 gene has recently been associated with infantile-onset NCL subtype CLN14 and PME type 3 (EPM3). Conclusion KCTD7 mutation testing should be considered in children with suspected infantile NCL when first line diagnostic tests are normal.

ASAH1 Mutation in a Boy with Non-5q SMA and Progressive Myoclonic Epilepsy

Introduction: Spinal muscular atrophies (SMA) represent a clinically and genetically heterogeneous group of lower motor neuron diseases, most frequently caused by mutations in the SMN1 gene (5q SMA). Recently, mutations in ASAH1 were found to be responsible for a rare and distinct phenotype of SMA associated with progressive myoclonic epilepsy (PME). Here, we report on the case of a 14-year-old boy with non 5q-SMA who later suffered from severe and drug-resistant myoclonic epilepsy. Case Report: Born to consanguineous, Turkish parents after an uneventful pregnancy, the boy showed normal early developmental milestones and was able to walk at the age of 12 months. First physical examination at the age of 3 years revealed proximal weakness and muscular atrophy, reduced deep tendon reflexes, and fasciculations of the tongue. CK was normal and SMN gene deletion study was negative. EMG and a muscle biopsy showed a denervation process, spinal and brain MRI were normal. By the age of 9 years, the patient developed respiratory insufficiency and noninvasive ventilation was started. At the age of 12 years, he began to have myoclonic and generalized seizures and the EEG demonstrated intensive epileptiform activity with bilateral spike and slow waves. To date, the epilepsy is progressive and resistant to therapy and mental functions deteriorate. Neurometabolic work-up revealed no abnormalities. Finally, molecular genetic analysis disclosed a homozygous mutation in ASAH1 (c.125C > T). Conclusion: SMA associated with PME in childhood (SMA–PME) represents a rare clinical and genetic entity caused by ASAH1 mutations. Therefore, the occurrence of myoclonic seizures in a patient with SMA-like phenotype and negative SMN gene deletion test should result in molecular genetic analysis of the ASAH1 gene. Keywords: ASAH1 mutation, spinal muscular atrophy, progressive myoclonic epilepsy.