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Background: Autosomal recessively inherited progressive myoclonic epilepsy of Lafora, which is also known as Lafora disease, is a fatal neurodegenerative disorder. It affects individuals in late childhood or early adolescence and presents with symptoms of progressive mental and physical deterioration. This disease is caused by pathogenic genetic variants in either of two genes: EPM2A on chromosome 6q24, encoding laforin, or NHLRC1 (EPM2B) on chromosome 6p22, encoding malin. Case presentation: In this study, we report a clinical and molecular investigation of Lafora disease segregating in a consanguineous Pakistani family. The proband presented with symptoms of rapidly progressive myoclonic epilepsy, but laboratory studies were negative for Lafora bodies and ragged red fibres. Sanger DNA sequencing of the genomic DNA of the proband for EPM2A and NHLRC1 identified a previously reported pathogenic nonsense variant in NHLRC1 (NM_198586.3:c.793C > T), which encodes the E3 ubiquitin ligase called malin. The NHLRC1 variant was found in a homozygous state in the proband, predicting a premature stop codon at position 265 (NP_940988.2:p.Arg265Ter). If the mRNA escaped nonsense-mediated decay, it would result in a truncated protein lacking 130 amino acids, including three NHL (NCL-1, HT2A, LIN-41) repeats. Conclusions: Our study emphasizes the role of molecular genetic testing in patients presenting with symptoms of progressive myoclonic epilepsy. [ABSTRACT FROM AUTHOR]

Background and objectives: Progressive myoclonic epilepsy (PME) is a group of neurological disorders characterized by recurrent myoclonic seizures with progressive neurological deterioration. We investigated the genetics of three unrelated patients with PME from Mali, a country in sub-Saharan Africa highly underrepresented in genetic and genomic research. Methods: Participants were carefully examined and phenotyped. DNA was obtained for genetic analysis including whole exome sequencing (WES). In silico prediction tools and ACMG criteria were used to assess the deleteriousness of putative candidate variants. Results: Pedigree analysis suggests autosomal recessive inheritance patterns for one family and sporadic forms of PME for the two other cases. WES identified novel homozygous missense variants in all the three patients, one each for NHLRC1 , EPM2A , and NEU1. The sequence variants segregated with PME in each family and in silico studies including protein 3D structures, CADD scores and ACMG criteria suggested that they were damaging. Discussion: PME is a group of clinically heterogeneous neurological disorders. Most reported cases in the literature are from European background with only a few cases described in North Africa. We report here novel pathogenic variants in three different genes causing PME phenotypes in three unrelated Malian patients, suggesting that genetic studies of underrepresented populations may expand the genetic epidemiology of PME. These findings also emphasize the need for inclusive genetic research to ensure a more targeted diagnostic and therapeutic approaches for diverse patient populations. [ABSTRACT FROM AUTHOR]

Background: Progressive myoclonus epilepsy (PME) is a neurodegenerative disorder marked by recurrent seizures and progressive myoclonus. To date, based on the phenotypes and causal genes, more than 40 subtypes of PMEs have been identified, and more remain to be characterized. Our study is aimed at identifying the aberrant gene(s) possibly associated with PMEs in two siblings born to asymptomatic parents, in the absence of known genetic mutations. Methods: Clinical assessments and molecular analyses, such as the repeat expansion test for CSTB; SCA1, 2, 3, 6, and 7; whole exome sequencing (WES); and mitochondrial genome sequencing coupled with computational analysis, were performed. Results: A family‐based segregation analysis of WES data was performed to identify novel genes associated with PMEs. The potassium channel, KCNH8 [c.298T>C; (p.Tyr100His)], a DNA repair gene, regulator of telomere elongation helicase 1 (RTEL1) [c.691G>T; (p.Asp231Tyr)] and long noncoding RNA, RTEL1-TNFRSF6B [chr20:62298898_G>T; NR_037882.1, hg19] were among the candidate genes that were found to be associated with PMEs. These homozygous variations in siblings belong to genes with a loss‐of‐function intolerant (pLI) score of ≤ 0.86, expected to be detrimental by multiple computational analyses, and were heterozygous in parents. Additionally, computational analysis and the expression of RTEL1 and RTEL1-TNFRSF6B revealed that RTEL1-TNFRSF6B may modulate RTEL1 via hsa‐miR‐3529‐3p. In the patient with the severe phenotype, a further deleterious mutation in SLC22A17 was identified. No de novo variants specific to these probands were identified in the mitochondrial genome. Conclusions: Our study is the first to report variants in KCNH8, RTEL1, and RTEL1-TNFRSF6B among PME cases. These genes when characterized fully may shed light on pathogenicity and have the potential to be used in the diagnosis of PME. [ABSTRACT FROM AUTHOR]

Background: Children diagnosed with subacute sclerosing panencephalitis (SSPE) display a range of neuroimaging abnormalities during different stages of the disease, but their exact clinical significance remains unclear. Methods: In this retrospective cohort study, our objective was to examine magnetic resonance imaging (MRI) abnormalities in the brains of patients aged 18 years or younger with subacute sclerosing panencephalitis. We aimed to correlate these MRI abnormalities with clinical severity, sociodemographic variables, electroencephalographic (EEG) abnormalities, and cerebrospinal anti-measles antibody titers. Results: The study included 112 cases of subacute sclerosing panencephalitis (mean age at onset: 8.9 ± 2.6 years). MRI analysis at the time of presentation revealed the following abnormalities: subcortical white matter signal changes (n = 95), periventricular white matter signal changes (n = 76), splenium of corpus callosum involvement (n = 39), diffuse corpus callosum involvement (n = 27), cerebral atrophy (n = 35), basal ganglia involvement (n = 10), and brain stem involvement (n = 2). Notably, subcortical white matter involvement, periventricular white matter involvement, diffuse corpus callosum involvement, and basal ganglia involvement were more prevalent in patients with stage III and IV subacute sclerosing panencephalitis (P <.05 for all). Cerebral atrophy was also significantly more common in patients with stage III compared to those with stage IV subacute sclerosing panencephalitis (P <.0001). However, no substantial positive or negative associations were found between MRI findings and EEG abnormalities, other sociodemographic/clinical variables, and cerebrospinal fluid measles-specific antibody titers (P >.05). Conclusion: Early in the disease progression of subacute sclerosing panencephalitis, the temporoparietal and parietooccipital regions of the subcortical white matter are affected. Neuroimaging abnormalities exhibit a stronger association with Jabbour's clinical staging, but do not show significant associations with other clinical, sociodemographic, and EEG features. [ABSTRACT FROM AUTHOR]

Background and objectivesProgressive myoclonic epilepsy (PME) is a group of neurological disorders characterized by recurrent myoclonic seizures with progressive neurological deterioration. We investigated the genetics of three unrelated patients with PME from Mali, a country in sub-Saharan Africa highly underrepresented in genetic and genomic research.MethodsParticipants were carefully examined and phenotyped. DNA was obtained for genetic analysis including whole exome sequencing (WES). In silico prediction tools and ACMG criteria were used to assess the deleteriousness of putative candidate variants.ResultsPedigree analysis suggests autosomal recessive inheritance patterns for one family and sporadic forms of PME for the two other cases. WES identified novel homozygous missense variants in all the three patients, one each for NHLRC1, EPM2A, and NEU1. The sequence variants segregated with PME in each family and in silico studies including protein 3D structures, CADD scores and ACMG criteria suggested that they were damaging.DiscussionPME is a group of clinically heterogeneous neurological disorders. Most reported cases in the literature are from European background with only a few cases described in North Africa. We report here novel pathogenic variants in three different genes causing PME phenotypes in three unrelated Malian patients, suggesting that genetic studies of underrepresented populations may expand the genetic epidemiology of PME. These findings also emphasize the need for inclusive genetic research to ensure a more targeted diagnostic and therapeutic approaches for diverse patient populations.

Objective: KCTD7‐related progressive myoclonic epilepsy (PME) is a rare autosomal‐recessive disorder. This study aimed to describe the clinical details and genetic variants in a large international cohort. Methods: Families with molecularly confirmed diagnoses of KCTD7‐related PME were identified through international collaboration. Furthermore, a systematic review was done to identify previously reported cases. Salient demographic, epilepsy, treatment, genetic testing, electroencephalographic (EEG), and imaging‐related variables were collected and summarized. Results: Forty‐two patients (36 families) were included. The median age at first seizure was 14 months (interquartile range = 11.75–22.5). Myoclonic seizures were frequently the first seizure type noted (n = 18, 43.9%). EEG and brain magnetic resonance imaging findings were variable. Many patients exhibited delayed development with subsequent progressive regression (n = 16, 38.1%). Twenty‐one cases with genetic testing available (55%) had previously reported variants in KCTD7, and 17 cases (45%) had novel variants in KCTD7 gene. Six patients died in the cohort (age range = 1.5–21 years). The systematic review identified 23 eligible studies and further identified 59 previously reported cases of KCTD7‐related disorders from the literature. The phenotype for the majority of the reported cases was consistent with a PME (n = 52, 88%). Other reported phenotypes in the literature included opsoclonus myoclonus ataxia syndrome (n = 2), myoclonus dystonia (n = 2), and neuronal ceroid lipofuscinosis (n = 3). Eight published cases died over time (14%, age range = 3–18 years). Significance: This study cohort and systematic review consolidated the phenotypic spectrum and natural history of KCTD7‐related disorders. Early onset drug‐resistant epilepsy, relentless neuroregression, and severe neurological sequalae were common. Better understanding of the natural history may help future clinical trials. [ABSTRACT FROM AUTHOR]

This article discusses a rare genetic disorder called Action Myoclonus with Renal Failure (AMRF) syndrome, also known as progressive myoclonic epilepsy (PME) type 4. The disorder is characterized by progressive myoclonus, ataxia, dysarthria, epilepsy, and renal failure. The article presents a case report of two siblings with AMRF due to mutations in the SCARB2 gene. The siblings exhibited variable presentations of the disorder, with the proband experiencing more severe symptoms including myoclonus, ataxia, and seizures, while the elder brother had a milder phenotype with gait ataxia and infrequent seizures. The article highlights the phenotypic heterogeneity of AMRF and emphasizes the importance of considering AMRF in cases of PME with a family history of renal failure. [Extracted from the article]

The progressive myoclonus epilepsies (PME) are a diverse group of disorders that feature both myoclonus and seizures that worsen gradually over a variable timeframe. While each of the disorders is individually rare, they collectively make up a non-trivial portion of the complex epilepsy and myoclonus cases that are seen in tertiary care centers. The last decade has seen substantial progress in our understanding of the pathophysiology, diagnosis, prognosis, and, in select disorders, therapies of these diseases. In this scoping review, we examine English language publications from the past decade that address diagnostic, phenotypic, and therapeutic advances in all PMEs. We then highlight the major lessons that have been learned and point out avenues for future investigation that seem promising. [ABSTRACT FROM AUTHOR]

Among different types of Progressive Myoclonic Epilepsy (PME), Lafora disease is an autosomal recessive disorder, with age of onset 6-19 years. It is quickly progressive, and death occurs within 10 years. It is a glycogen metabolism disorder characterized by the presence of inclusion bodies, known as Lafora bodies within the cytoplasm of the skin, liver, breast and muscle. Lafora disease presents as a neurodegenerative disorder with difficult to control seizures mostly like progressive myoclonic epilepsy. But the disease may also present with multiple types of seizures like generalized tonic clonic, focal with secondary generalization, myoclonic, absence etc. Patient may also present with psychomotor regression with ataxia, dysarthria, dementia, visual hallucination etc. Electroencephalogram (EEG) shows generalized spike/polyspikes and waves with photosensitivity and background slowing. Diagnosis is further confirmed by presence of inclusion bodies (Lafora body) with typical histological findings on skin biopsy and genetic testing. Here we present a case of Lafora disease that presented with progressive myoclonic epilepsy and generalized tonic clonic seizure. We took proper history, did meticulous clinical examination and investigated her at our institute. We confirmed the patient having Lafora disease with typical histological findings that is presence of Lafora body on skin biopsy taken from axilla. Then treatment was given to the patient accordingly and proper counseling was done about the disease and its prognosis. [ABSTRACT FROM AUTHOR]

The progressive myoclonus epilepsies (PMEs) are a heterogeneous group of neurodegenerative disorders, typically presenting in late childhood. An etiologic diagnosis is achieved in about 80% of patients with PME, and genome‐wide molecular studies on remaining, well‐selected, undiagnosed cases can further dissect the underlying genetic heterogeneity. Through whole‐exome sequencing (WES), we identified pathogenic truncating variants in the IRF2BPL gene in two, unrelated patients presenting with PME. IRF2BPL belongs to the transcriptional regulators family and it is expressed in multiple human tissues, including the brain. Recently missense and nonsense mutations in IRF2BPL were found in patients presenting with developmental delay and epileptic encephalopathy, ataxia, and movement disorders, but none with clear PME. We identified 13 other patients in the literature with myoclonic seizures and IRF2BPL variants. There was no clear genotype–phenotype correlation. With the description of these cases, the IRF2BPL gene should be considered in the list of genes to be tested in the presence of PME, in addition to patients with neurodevelopmental or movement disorders. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the electro-clinical features in association with laboratory and instrumental correlates of neurodegeneration to detect the progression of Lafora disease (LD). Methods: We investigated the electro-clinical longitudinal data and CSF Ab42, p-tau181 and t-tauAg, amyloid, and 18F-FDG PET of five unrelated LD families. Results: Three progressive electro-clinical stages were identified. The early phase was characterized by rare, generalized tonic-clonic and focal visual seizures, followed by the occurrence of myoclonus after a period ranging from 2 to 12 months. The intermediate stage, usually occurring 2 years after the onset of epilepsy, is characterized by a worsening of epilepsy and myoclonus associated with progressive dementia and cerebellar signs. Finally, the late stage, evolving after a mean period of 7 ± 1.41 years from the onset of the disease, was characterized by gait ataxia resulting in bedriddenness, severe dementia, daily/pluri-daily myoclonus, drug-resistant epilepsy, clusters of seizures or status epilepticus, and medical complications. Amyloid (CSF Ab42, amyloid PET) and neurodegenerative (CSF p-tau181 and t-tauAg, FDG-PET) biomarkers indicate a pattern of cognitive impairment of the non-Alzheimer's disease type. A total of 80% of the LD patients showed more severe hypometabolism in the second FDG-PET scan compared to the first scan performed in a lower phase; the lateral temporal lobe and the thalamus hypometabolism were associated with the presence of intermediate or late phase. Conclusions: Three electroclinical and 18F-FDG PET evolutive stages are useful biomarkers for the progression of LD and could help to evaluate the effcacy of new disease-modifying treatments. The combination of traditional CSF biomarkers improves the diagnostic accuracy of cognitive decline in LD patients, indicating a cognitive impairment of the non-Alzheimer's disease type. [ABSTRACT FROM AUTHOR]

The progressive myoclonic epilepsies (PMEs) are a group of rare neurodegenerative diseases characterized by myoclonus, epileptic seizures, and progressive neurological deterioration with cerebellar involvement. They include storage diseases like Gaucher disease, Lafora disease, and forms of neuronal ceroid lipofuscinosis (NCL). To date, 13 NCLs have been reported (CLN1-CLN8, CLN10-CLN14), associated with mutations in different genes. These forms, which affect both children and adults, are characterized by seizures, cognitive and motor impairments, and in most cases visual loss. In NCLs, as in other PMEs, central nervous system (CNS) neurodegeneration is widespread and involves different subpopulations of neurons. One of the most affected regions is the cerebellar cortex, where motor and non-motor information is processed and transmitted to deep cerebellar nuclei through the axons of Purkinje cells (PCs). PCs, being GABAergic, have an inhibitory effect on their target neurons, and provide the only inhibitory output of the cerebellum. Degeneration of PCs has been linked to motor impairments and epileptic seizures. Seizures occur when some insult upsets the normal balance in the CNS between excitatory and inhibitory impulses, causing hyperexcitability. Here we review the role of PCs in epilepsy onset and progression following their PME-related loss. In particular, we focus on the involvement of PCs in seizure phenotype in NCLs, highlighting findings from case reports and studies of animal models in which epilepsy can be linked to PC loss.

PurposeTo evaluate the electro-clinical features in association with laboratory and instrumental correlates of neurodegeneration to detect the progression of Lafora disease (LD).MethodsWe investigated the electro-clinical longitudinal data and CSF Aβ42, p-tau181 and t-tauAg, amyloid, and 18F-FDG PET of five unrelated LD families.ResultsThree progressive electro-clinical stages were identified. The early phase was characterized by rare, generalized tonic-clonic and focal visual seizures, followed by the occurrence of myoclonus after a period ranging from 2 to 12 months. The intermediate stage, usually occurring 2 years after the onset of epilepsy, is characterized by a worsening of epilepsy and myoclonus associated with progressive dementia and cerebellar signs. Finally, the late stage, evolving after a mean period of 7 ± 1.41 years from the onset of the disease, was characterized by gait ataxia resulting in bedriddenness, severe dementia, daily/pluri-daily myoclonus, drug-resistant epilepsy, clusters of seizures or status epilepticus, and medical complications. Amyloid (CSF Aβ42, amyloid PET) and neurodegenerative (CSF p-tau181 and t-tauAg, FDG-PET) biomarkers indicate a pattern of cognitive impairment of the non-Alzheimer's disease type. A total of 80% of the LD patients showed more severe hypometabolism in the second FDG-PET scan compared to the first scan performed in a lower phase; the lateral temporal lobe and the thalamus hypometabolism were associated with the presence of intermediate or late phase.ConclusionsThree electroclinical and 18F-FDG PET evolutive stages are useful biomarkers for the progression of LD and could help to evaluate the efficacy of new disease-modifying treatments. The combination of traditional CSF biomarkers improves the diagnostic accuracy of cognitive decline in LD patients, indicating a cognitive impairment of the non-Alzheimer's disease type.

Abstract Background Biallelic pathogenic variants in the SCARB2 gene have been associated with action myoclonus-renal failure (AMRF) syndrome. Even though SCARB2 associated phenotype has been reported to include typical neurological characteristics, depending on the localization and the feature of the pathogenic variants, clinical course and the presentations have been shown to differ. Case presentation Whole exome sequencing (WES) analysis revealed a homozygous truncating variant (p.N45MfsX88) in SCARB2 gene in the index case, and subsequent sanger sequencing analysis validated the variant in all affected family members from a Turkish family with the clinical characteristics associated with AMRF and related disorders. Intrafamilial clinical heterogeneity with common features including dysarthria, tremor and proteinuria, and distinct features such as peripheral neuropathy (PNP), myoclonus and seizures between the affected cases, was observed in the family. In-depth literature review enabled the detailed investigation of the reported variants associated with AMRF and suggested that while the type of the variant did not have a major impact on the course of the clinical characteristics, only the C terminal localization of the pathogenic variant significantly affected the clinical presentation, particularly the age at onset (AO) of the disease. Conclusions In this study we showed that biallelic SCARB2 pathogenic variants might cause a spectrum of common and distinct features associated with AMRF. Of those features while the common features include myoclonus (100%), ataxia (96%), tonic clonic seizures (82%), dysarthria (68%), tremor (65%), and renal impairment (62%), the uncommon features involve PNP (17%), hearing loss (6.8%), and cognitive impairment (13.7%). AO has been found to be significantly higher in the carriers of the p.G462DfsX34 pathogenic variant. SCARB2 pathogenic variants have not been only implicated in AMRF but also in the pathogenesis of Parkinson’s disease (PD) and Gaucher disease (GD), suggesting the importance of genetic and functional studies in the clinical and the diagnostic settings. Given the proven role of SCARB2 gene in the pathogenesis of AMRF, PD and GD with a wide spectrum of clinical symptoms, investigation of the possible modifiers, such as progranulin and HSP7, has a great importance.

This study describes a patient with progressive myoclonic epilepsy-11 (EPM-11), which follows autosomal dominant inheritance caused by a novel SEMA6B variant. Most patients develop this disease during infancy or adolescence with action myoclonus, generalized tonic-clonic seizures (GTCS), and progressive neurological deterioration. No cases of adult-onset EPM-11 have been reported yet. Here, we present one case of adult-onset EPM-11 who experienced gait instability, seizures, and cognitive impairment, and harbored a novel missense variant, c.432C>G (p.C144W). Our findings provide a foundation for a better understanding of the phenotypic and genotypic profiles of EPM-11. Further functional studies are recommended to elucidate the pathogenesis of this disease. [ABSTRACT FROM AUTHOR]

Objective: Progressive myoclonic epilepsy type 1 (EPM1) is caused by biallelic alterations in the CSTB gene, most commonly dodecamer repeat expansions. Although transcranial magnetic stimulation (TMS)–induced long‐interval intracortical inhibition (LICI) was previously reported to be normal in EPM1, short‐interval intracortical inhibition (SICI) was reduced. We explored the association between these measures and the clinical and genetic features in a separate group of patients with EPM1. Methods: TMS combined with electromyography was performed under neuronavigation. LICI was induced with an inter‐stimulus interval (ISI) of 100 ms, and SICI with ISIs of 2 and 3 ms, and their means (mSICIs) were expressed as the ratio of conditioned to unconditioned stimuli. LICI and mSICI were compared between patients and controls. Nonparametric correlation was used to study the association between inhibition and parameters of clinical severity, including the Unified Myoclonus Rating Scale (UMRS); among patients with EPM1 due to biallelic expansion repeats, also the association with the number of repeats was assessed. Results: The study protocol was completed in 19 patients (15 with biallelic expansion repeats and 4 compound heterozygotes), and 7 healthy, age‐ and sex‐matched control participants. Compared to controls, patients demonstrated significantly less SICI (median mSICI ratio 1.18 vs 0.38; p <.001). Neither LICI nor SICI was associated with parameters of clinical severity. In participants with biallelic repeat expansions, the number of repeats in the more affected allele (greater repeat number [GRN]) correlated with LICI (rho = 0.872; p <.001) and SICI (rho = 0.689; p =.006). Significance: Our results strengthen the finding of deranged γ‐aminobutyric acid (GABA)ergic inhibition in EPM1. LICI and SICI may have use as markers of GABAergic impairment in future trials of disease‐modifying treatment in this condition. Whether a higher number of expansion repeats leads to greater GABAergic impairment warrants further study. [ABSTRACT FROM AUTHOR]

Background: Progressive myoclonus epilepsy (PME) is a group of heterogeneous genetic disorders characterized by action myoclonus, epileptic seizures, and progressive neurologic deterioration with onset of symptoms in adolescence and adulthood. Unverricht–Lundborg disease (ULD) is the most common type of PME in high-income countries; however, it is under-reported from India due to challenges in clinical recognition and establishment of diagnosis due to lack of availability of genetic studies. Clinical Description: We herewith report three siblings (two girls and a boy) born out of a third-degree consanguineous marriage, with onset of “difficult-to-treat” seizures since early adolescence, with concurrent action myoclonus and ataxia. All three had a waxing and waning course. Electroencephalography exhibited generalized spike-wave and polyspike-wave discharges with photosensitivity while neuroimaging was normal. Management and Outcome: The possibility of PME was considered in view of the clinical phenotype and strong family history. Following detailed elicitation of history, focused physical examination, and rational investigative work-up specific molecular genetic testing were planned for ULD. This showed homozygous expansion of dodecamer (set of 12 nucleotides) repeat in the cystatin B gene in all the three affected siblings. The parents were heterozygous carriers. Genetic counseling was undertaken and anticonvulsant drugs (ACDs) modified accordingly. The definitive diagnosis helped in accurate prognostication and management to improve the quality of life of all three siblings. Conclusion: Clinicians should consider a specific epilepsy syndrome in patients with onset of symptoms in adolescence. ULD is a type of PME with a relatively better course of illness. Establishing the diagnosis has implications on the extent of investigative workup, choice of ACD, and prognosis.

Lafora disease is a rare genetic disease caused by the accumulation of malformed glycogen products in the tissues. The disease usually manifests with idiopathic generalized tonic colonic seizures with poor response to antiepileptic drugs (AEDs). We report the case of a 19-year-old girl with the chief complaint of generalized refractory seizures, jerky movement, and cognitive deterioration with a positive history of epilepsy in her younger brother. The disease onset was at the age of 16 with jerky movement and blurred vision. She was admitted to our ward to have a long-term video EEG monitoring for further evaluation. Clinical presentation accompanied with abnormal EEG characteristics for Lafora disease, and the positive familial history were highly suggestive of Lafora disease. The disease was confirmed with genetic testing by which the mutation of EPM2A was detected.

Progressive myoclonic epilepsy (PME) is characterized by prominent myoclonus, generalized tonic-clonic seizures, and less often focal, tonic, or absence seizures. The KCNC1 mutation is responsible for specific clinical phenotype of PME which has been defined as myoclonic epilepsy and ataxia due to potassium channel mutation (MEAK). We present a case of a 44 years-old male patient with genetically proven MEAK who underwent subthalamic nucleus/substantia nigra (STN/SNr) deep brain stimulation (DBS) for his pharmacological-refractory myoclonus and drug-resistant epilepsy (DRE). Since the age of 4–5 years, the patient had been suffering from intention tremor, and later the myoclonic jerks, ataxia involving the upper limbs and walking difficulties worsened. The first bilateral tonic-clonic seizure (BTCS) occurred at the age of 22. The patient agreed to staged bilateral implantation of DBS electrodes placed in the STN/SNr region. The follow-up lasts more than 24 months. The myoclonic jerks assessed by Unified Myoclonus Rating Scale (UMRS) were reduced by nearly 70 % and BTCS was completely abolished. The patient’s ataxia and dysarthria did not improve. Early diagnosis with genetic testing may significantly help in counseling patients with PME and enables to undertake the surgical approach targeting the STN/SNr.

Krabbe disease (KD), also known as globoid cell leukodystrophy, is a rare autosomal recessive condition caused by mutations in the galactocerebrosidase (GALC) gene. KD is more common in infants and young children than in adults. We reported the case of an adult-onset KD presenting with progressive myoclonic epilepsy (PME) and cortical lesions mimicking mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS) syndrome. The whole-exome sequencing (WES) identified a pathogenic homozygous missense mutation of the GALC gene. Parents of the patient were heterozygous for the mutation. The clinical, electrophysiological, and radiological data of the patient were retrospectively analyzed. The patient was a 24-year-old woman presenting with generalized seizures, progressive cognitive decline, psychiatric symptoms, gait ataxia, and action-induced myoclonus. The brain magnetic resonance imaging (MRI) revealed a right occipital cortical ribbon sign without any other damage. This single case expands the clinical phenotypes of adult-onset KD. [ABSTRACT FROM AUTHOR]

Lafora disease is a rare refractory epilepsy that results in death. This report highlights two cases of lafora disease and introduces a novel mutation in the patients. A review of the pathophysiology and future therapies is reviewed. [ABSTRACT FROM AUTHOR]

Brain aging is characterized by a gradual decline in cellular homeostatic processes, thereby losing the ability to respond to physiological stress. At the anatomical level, the aged brain is characterized by degenerating neurons, proteinaceous plaques and tangles, intracellular deposition of glycogen, and elevated neuroinflammation. Intriguingly, such age-associated changes are also seen in neurodegenerative disorders suggesting that an accelerated aging process could be one of the contributory factors for the disease phenotype. Amongst these, the genetic forms of progressive myoclonus epilepsy (PME), resulting from loss-of-function mutations in genes, manifest symptoms that are common to age-associated disorders, and genes mutated in PME are involved in the cellular homeostatic processes. Intriguingly, the incidence and/or onset of epileptic seizures are known to increase with age, suggesting that physiological changes in the aged brain might contribute to increased susceptibility to seizures. We, therefore, hypothesized that the expression level of genes implicated in PME might decrease with age, thereby leading to a compromised neuronal response towards physiological stress and hence neuroinflammation in the aging brain. Using mice models, we demonstrate here that the expression level of PME genes shows an inverse correlation with age, neuroinflammation, and compromised heat shock response. We further show that the pharmacological suppression of neuroinflammation ameliorates seizure susceptibility in aged animals as well as in animal models for a PME. Taken together, our results indicate a functional role for the PME genes in normal brain aging and that neuroinflammation could be a major contributory player in susceptibility to seizures. [ABSTRACT FROM AUTHOR]

Abstract Objective Clinical care of rare and complex epilepsies is challenging, because evidence‐based treatment guidelines are scarce, the experience of many physicians is limited, and interdisciplinary treatment of comorbidities is required. The pathomechanisms of rare epilepsies are, however, increasingly understood, which potentially fosters novel targeted therapies. The objectives of our survey were to obtain an overview of the clinical practice in European tertiary epilepsy centers treating patients with 5 arbitrarily selected rare epilepsies and to get an estimate of potentially available patients for future studies. Methods Members of the European Reference Network for rare and complex epilepsies (EpiCARE) were invited to participate in a web‐based survey on clinical practice of patients with Dravet syndrome, tuberous sclerosis complex (TSC), autoimmune encephalitis, and progressive myoclonic epilepsies including Unverricht Lundborg and Unverricht‐like diseases. A consensus‐based questionnaire was generated for each disease. Results Twenty‐six of 30 invited epilepsy centers participated. Cohorts were present in most responding centers for TSC (87%), Dravet syndrome (85%), and autoimmune encephalitis (71%). Patients with TSC and Dravet syndrome represented the largest cohorts in these centers. The antiseizure drug treatments were rather consistent across the centers especially with regard to Dravet syndrome, infantile spasms in TSC, and Unverricht Lundborg / Unverricht‐like disease. Available, widely used targeted therapies included everolimus in TSC and immunosuppressive therapies in autoimmune encephalitis. Screening for comorbidities was routinely done, but specific treatment protocols were lacking in most centers. Significance The survey summarizes the current clinical practice for selected rare epilepsies in tertiary European epilepsy centers and demonstrates consistency as well as heterogeneity in the treatment, underscoring the need for controlled trials and recommendations. The survey also provides estimates for potential participants of clinical trials recruited via EpiCARE, emphasizing the great potential of Reference Networks for future studies to evaluate new targeted therapies and to identify novel biomarkers.

Aims: Progressive Myoclonic Epilepsy (PME)is a heterogeneous group of pathologies associating epileptic seizures and other neurological and non-neurological disorders. We aim to characterize patients with symptoms of PME and identify the underlying genetic disorder. Methodology: After informed consent, the patients seen in the protocol for hereditary neurological diseases and presenting signs of epilepsy without a secondary cause were clinically evaluated over a three-year period in the Department of Neurology of the CHU Point "G". EEG, brain imaging and laboratory tests were performed to consolidate our diagnosis. DNA was extracted for genetic analysis. Results: 141 families including five families with PME totaling eight cases were enrolled. The dominant symptoms in our patients were myoclonus in 87.5% (N = 8), followed by GTCS and cognitive impairment in 50%, each. A notion of parental consanguinity was found in 60% and autosomal recessive transmission evoked in 80% (N = 5). The EEG was pathological in 62.5% and imaging showed ponto-cerebellar atrophy in 25% (N = 8). The combination of sodium valproate and clonazepam was the main treatment. One case of death was recorded. Conclusion: We report cases of PME in Mali with a possibility of discovering new genes. [ABSTRACT FROM AUTHOR]

Abstract Background A number of genetic syndromes associated with variants in the BSCL2/seipin gene have been identified. Variants that cause skipping of exon 7 are associated with progressive encephalopathy with/without lipodystrophy (PELD), which is characterized by the development of progressive myoclonic epilepsy at a young age, severe progressive neurological impairment, and early death, often in childhood. Because the genetic basis of PELD is similar to that of congenital lipodystrophy type 2, we hypothesized that a patient with PELD may respond to treatments approved for other congenital lipodystrophic syndromes. Case presentation We describe a 5-year-old boy with an extremely rare phenotype involving severe progressive myoclonic epilepsy who received metreleptin (a recombinant analogue of leptin) to control metabolic abnormalities. At the age of two, he had no subcutaneous adipose tissue, with hypertriglyceridemia, hypertransaminasemia and hepatic steatosis. He also had a moderate psychomotor delay and generalized tonic seizures. At 4 years, he had insulin resistance, hypercholesterolemia, hypertriglyceridemia, mild hepatosplenomegaly and mild hepatic steatosis; he began a hypolipidemic diet. Severe psychomotor delay and myoclonic/myoclonic atonic seizures with absences was evident. At 5 years of age, metreleptin 0.06 mg/kg/day was initiated; after 2 months, the patient’s lipid profile improved and insulin resistance resolved. After 1 year of treatment, hepatic steatosis improved and abdominal ultrasound showed only mild hepatomegaly. Seizure frequency decreased but was not eliminated during metreleptin therapy. Conclusions Metreleptin may be used to control metabolic disturbances and may lead to better seizure control in children with PELD.

Abstract Background Progressive myoclonic epilepsy (PME) is a group of neurodegenerative diseases with genetic heterogeneity and phenotypic similarities, and many cases remain unknown of the genetic causes. This study is aim to summarize the clinical features and study the genetic causes of PME patients. Methods Sanger sequencing of the target gene, Next Generation Sequencing (NGS) panels of epilepsy, trio-based Whole Exome Sequencing (WES) and detection of cytosine-adenine-guanine (CAG) repeat number were used to investigate the genetic causes of PME patients. Results Thirty-eight children with PME whose seizure onset age ranged from 3 months to 12 years were collected from February 2012 to November 2019 in three hospitals in Beijing, China. The seizure types included myoclonic seizures (n = 38), focal seizures (n = 19), generalized tonic-clonie seizure (GTCS) (n = 13), absence seizures (n = 4), atonic seizures (n = 3), epileptic spasms (n = 2) and tonic seizures (n = 1). Twenty-seven cases were sporadic and 11 had family members affected. Established PME-related genes were identified in 30 out of 38 (78.9%) patients who had either recessively inherited or de novo heterozygous mutations. Among these 30 cases, there were 12 cases (31.6%) of neuronal ceroid lipofuscinoses (the causing gene contains TPP1, PPT1, CLN5, CLN6 and MFSD8), two cases of sialidosis (the causing gene is NEU1), two cases of neuronopathic Gaucher disease (the causing gene is GBA), one case of spinal muscular atrophy-progressive myoclonic epilepsy (the causing gene is ASAH1), four cases of KCNC1 mutation-related PME, four cases of KCTD7 mutation-related PME, two cases of TBC1D24 mutation-related PME, one case of GOSR2 related PME, and two of dentatorubral-pallidoluysian atrophy (the causing gene is ATN1). In total, 13 PME genes were identified in our cohort. The etiology was not clear in eight patients. Conclusion PME is a group of clinically and genetically heterogeneous diseases. Genetic diagnosis was clear in 78.9% of PME patients. Various of genetic testing methods could increase the rate of genetic diagnosis. Neuronal ceroid lipofuscinoses (NCL) is the most common etiology of PME in children. Nearly one third PME children were diagnosed with NCL. GOSR2 related PME was in our cohort in Asia for the first time.

Progressive myoclonic epilepsy (PME) is a group of rare diseases characterized by progressive myoclonus, cognitive impairment, ataxia, and other neurologic deficits. PME has high genetic heterogeneity, and more than 40 genes are reportedly associated with this disorder. SEMA6B encodes a member of the semaphorin family and was first reported to cause PME in 2020. Herein, we present a rare case of PME due to a novel SEMA6B gene mutation in a 6-year-old boy born to healthy non-consanguineous Chinese parents. His developmental milestones were delayed, and he developed recurrent atonic seizures and myoclonic seizures without fever at 3 years and 11 months of age. He experienced recurrent myoclonic seizures, non-convulsive status epilepticus (NCSE), atonic seizures, and atypical absence seizures during the last 2 years. At different time points since onset, valproic acid, levetiracetam, piracetam, and clobazam were used to control the intractable seizures. Notably, NCSE was controlled by a combination of piracetam with clobazam and valproic acid instead of intravenous infusion of midazolam and phenobarbital. Due to the limited number of cases reported to date, the clinical description of our case provides a better understanding of the genotype–phenotype correlations associated with PME and indicate that piracetam may be effective against NCSE in patients with SEMA6B-related PME.

Progressive myoclonic epilepsy is a group of neurodegenerative diseases with complex clinical and genetic heterogeneity, which is associated with spontaneous or action-induced myoclonus and progressive neurodegeneration. Since 2020, 4 families with progressive myoclonic epilepsy-11 [OMIM#618876] have been reported with a very limited spectrum of SEMA6B pathogenic variants. In our study, whole-exome sequencing was used in a proband from a nonconsanguineous Chinese family presenting with growth retardation and recurrent atonic seizures. A deletion mutation (c.1960_1978del, p.Leu654Argfs*25) in the last exon of SEMA6B was detected, which is a de novo variant and pathogenic. The new genetic evidence we reported here strengthened the gene-disease relationship, and the gene curation level between SEMA6B and progressive myoclonic epilepsy-11 became "strong" following the ClinGen SOP. Therefore, the results of this study broaden the mutation spectrum of SEMA6B in different ethnic groups and strengthen the gene-disease relationship between SEMA6B and progressive myoclonic epilepsy-11. [ABSTRACT FROM AUTHOR]

KCTD7 is a member of the potassium channel tetramerization domain-containing protein family and has been associated with progressive myoclonic epilepsy (PME), characterized by myoclonus, epilepsy, and neurological deterioration. Here we report four affected individuals from two unrelated families in which we identified KCTD7 compound heterozygous single nucleotide variants through exome sequencing. RNAseq was used to detect a non-annotated splicing junction created by a synonymous variant in the second family. Whole-cell patch-clamp analysis of neuroblastoma cells overexpressing the patients' variant alleles demonstrated aberrant potassium regulation. While all four patients experienced many of the common clinical features of PME, they also showed variable phenotypes not previously reported, including dysautonomia, brain pathology findings including a significantly reduced thalamus, and the lack of myoclonic seizures. To gain further insight into the pathogenesis of the disorder, zinc finger nucleases were used to generate kctd7 knockout zebrafish. Kctd7 homozygous mutants showed global dysregulation of gene expression and increased transcription of c-fos, which has previously been correlated with seizure activity in animal models. Together these findings expand the known phenotypic spectrum of KCTD7-associated PME, report a new animal model for future studies, and contribute valuable insights into the disease. [ABSTRACT FROM AUTHOR]

Introduction: Progressive myoclonic epilepsies (PMEs) are a heterogenous group of genetic diseases presenting with epilepsy, cognitive impairment, and severe action myoclonus, which can severely affect daily life activities and independent walking ability. Perampanel is a recent commercially available antiseizure medication with high efficacy against generalized seizures. Some reports supported the role of perampanel in ameliorating action myoclonus in PMEs. Here, we aimed to describe a case series and provide a systematic literature review on perampanel effects on PMEs.Methods: We report the perampanel effectiveness on myoclonus, daily life activities, and seizures on an original Italian multicenter case series of 11 individuals with PMEs. Then, using the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines, we performed a systematic review on perampanel effect on myoclonus and disability in PMEs. We searched PubMed, Scopus, and Google Scholar articles on perampanel and PMEs up to June 2020. No prospective trials were found. We reviewed 11 case series manuscripts reporting 104 cases of different PMEs.Results: Here, we are reporting the effectiveness of perampanel in five individuals affected by Unverricht–Lundborg disease, three by Lafora disease, two by sialidosis, and one by an undetermined PME. Nine out of 11 individuals improved their disability related to the action myoclonus (two with Lafora disease did not). Among the 104 persons with PMEs collected by the systematic review, we found that more than half of the patients receiving perampanel exhibited an amelioration of action myoclonus and, consequently, of their independence in daily life activities. The Unverricht–Lundborg disease seemed to show the best clinical response to perampanel, in comparison with the other more severe PMEs. A significant seizure reduction was achieved by almost all persons with active epilepsy. Only 11% of PME patients dropped out due to inefficacy.Conclusions: Perampanel demonstrated a beneficial effect with regard to action myoclonus, disability, and seizures and was well-tolerated in people with PMEs, independently from their genetic diagnosis. Given the limited scientific evidence, broader prospective trials should be encouraged.

Objective: Mutations in KCNC1 can cause severe neurological dysfunction, including intellectual disability, epilepsy, and ataxia. The Arg320His variant, which occurs in the voltage‐sensing domain of the channel, causes a highly penetrant and specific form of progressive myoclonus epilepsy with severe ataxia, designated myoclonus epilepsy and ataxia due to potassium channel mutation (MEAK). KCNC1 encodes the voltage‐gated potassium channel KV3.1, a channel that is important for enabling high‐frequency firing in interneurons, raising the possibility that MEAK is associated with reduced interneuronal function. Methods: To determine how this variant triggers MEAK, we expressed KV3.1bR320H in cortical interneurons in vitro and investigated the effects on neuronal function and morphology. We also performed electrophysiological recordings of oocytes expressing KV3.1b to determine whether the mutation introduces gating pore currents. Results: Expression of the KV3.1bR320H variant profoundly reduced excitability of mature cortical interneurons, and cells expressing these channels were unable to support high‐frequency firing. The mutant channel also had an unexpected effect on morphology, severely impairing neurite development and interneuron viability, an effect that could not be rescued by blocking KV3 channels. Oocyte recordings confirmed that in the adult KV3.1b isoform, R320H confers a dominant negative loss‐of‐function effect by slowing channel activation, but does not introduce potentially toxic gating pore currents. Significance: Overall, our data suggest that, in addition to the regulation of high‐frequency firing, KV3.1 channels play a hitherto unrecognized role in neuronal development. MEAK may be described as a developmental dendritopathy. [ABSTRACT FROM AUTHOR]

Introduction: Progressive myoclonic epilepsies (PMEs) are a heterogenous group of genetic diseases presenting with epilepsy, cognitive impairment, and severe action myoclonus, which can severely affect daily life activities and independent walking ability. Perampanel is a recent commercially available antiseizure medication with high efficacy against generalized seizures. Some reports supported the role of perampanel in ameliorating action myoclonus in PMEs. Here, we aimed to describe a case series and provide a systematic literature review on perampanel effects on PMEs. Methods: We report the perampanel effectiveness on myoclonus, daily life activities, and seizures on an original Italian multicenter case series of 11 individuals with PMEs. Then, using the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines, we performed a systematic review on perampanel effect on myoclonus and disability in PMEs. We searched PubMed, Scopus, and Google Scholar articles on perampanel and PMEs up to June 2020. No prospective trials were found. We reviewed 11 case series manuscripts reporting 104 cases of different PMEs. Results: Here, we are reporting the effectiveness of perampanel in five individuals affected by Unverricht–Lundborg disease, three by Lafora disease, two by sialidosis, and one by an undetermined PME. Nine out of 11 individuals improved their disability related to the action myoclonus (two with Lafora disease did not). Among the 104 persons with PMEs collected by the systematic review, we found that more than half of the patients receiving perampanel exhibited an amelioration of action myoclonus and, consequently, of their independence in daily life activities. The Unverricht–Lundborg disease seemed to show the best clinical response to perampanel, in comparison with the other more severe PMEs. A significant seizure reduction was achieved by almost all persons with active epilepsy. Only 11% of PME patients dropped out due to inefficacy. Conclusions: Perampanel demonstrated a beneficial effect with regard to action myoclonus, disability, and seizures and was well-tolerated in people with PMEs, independently from their genetic diagnosis. Given the limited scientific evidence, broader prospective trials should be encouraged. [ABSTRACT FROM AUTHOR]

Objective: Clinical care of rare and complex epilepsies is challenging, because evidence‐based treatment guidelines are scarce, the experience of many physicians is limited, and interdisciplinary treatment of comorbidities is required. The pathomechanisms of rare epilepsies are, however, increasingly understood, which potentially fosters novel targeted therapies. The objectives of our survey were to obtain an overview of the clinical practice in European tertiary epilepsy centers treating patients with 5 arbitrarily selected rare epilepsies and to get an estimate of potentially available patients for future studies. Methods: Members of the European Reference Network for rare and complex epilepsies (EpiCARE) were invited to participate in a web‐based survey on clinical practice of patients with Dravet syndrome, tuberous sclerosis complex (TSC), autoimmune encephalitis, and progressive myoclonic epilepsies including Unverricht Lundborg and Unverricht‐like diseases. A consensus‐based questionnaire was generated for each disease. Results: Twenty‐six of 30 invited epilepsy centers participated. Cohorts were present in most responding centers for TSC (87%), Dravet syndrome (85%), and autoimmune encephalitis (71%). Patients with TSC and Dravet syndrome represented the largest cohorts in these centers. The antiseizure drug treatments were rather consistent across the centers especially with regard to Dravet syndrome, infantile spasms in TSC, and Unverricht Lundborg / Unverricht‐like disease. Available, widely used targeted therapies included everolimus in TSC and immunosuppressive therapies in autoimmune encephalitis. Screening for comorbidities was routinely done, but specific treatment protocols were lacking in most centers. Significance: The survey summarizes the current clinical practice for selected rare epilepsies in tertiary European epilepsy centers and demonstrates consistency as well as heterogeneity in the treatment, underscoring the need for controlled trials and recommendations. The survey also provides estimates for potential participants of clinical trials recruited via EpiCARE, emphasizing the great potential of Reference Networks for future studies to evaluate new targeted therapies and to identify novel biomarkers. [ABSTRACT FROM AUTHOR]

Lafora disease is a rare and fatal form of progressive myoclonic epilepsy typically occurring early in adolescence. The disease results from mutations in the EPM2A gene, encoding laforin, or the EPM2B gene, encoding malin. Laforin and malin work together in a complex to control glycogen synthesis and prevent the toxicity produced by misfolded proteins via the ubiquitin-proteasome system. Disruptions in either protein cause alterations in this complex, leading to the formation of Lafora bodies containing abnormal, insoluble, and hyperphosphorylated forms of glycogen. We used the Epm2a -/- knockout mouse model of Lafora disease to apply gene therapy by administering intracerebroventricular injections of a recombinant adeno-associated virus carrying the human EPM2A gene. We evaluated the effects of this treatment through neuropathological studies, behavioral tests, video-electroencephalography, electrophysiological recordings, and proteomic/phosphoproteomic analysis. Gene therapy ameliorated neurological and histopathological alterations, reduced epileptic activity and neuronal hyperexcitability, and decreased the formation of Lafora bodies. Moreover, differential quantitative proteomics and phosphoproteomics revealed beneficial changes in various molecular pathways altered in Lafora disease. Our results represent proof of principle for gene therapy with the coding region of the human EPM2A gene as a treatment for EPM2A-related Lafora disease., Competing Interests: Declaration of interests The authors report no competing interests., (Copyright © 2024 The American Society of Gene and Cell Therapy. Published by Elsevier Inc. All rights reserved.)

Cerebrotendinous Xanthomatosis (CTX) is a rare autosomal-recessive inborn disorder of bile acid metabolism due to mutations in the CYP27A1 gene. It presents with a diverse range of neurological and non-neurological symptoms. We present a case of CTX with a progressive myoclonic epilepsy (PME) like phenotype and a family history of CTX. The proband had a generalized epilepsy with prominent myoclonus. He also had intellectual decline, ataxia, bipyramidal dysfunction and peripheral neuropathy. The younger sibling had a milder generalized epilepsy without myoclonus along with behavioral issues, ataxia, neuropathy, and prominent tendon xanthomas. Both the siblings had developmental cataracts. MRI Brain of both had dentate hyperintensities with cerebellar atrophy. The proband’s EEG showed severe background slowing with multifocal interictal discharges. Targeted gene of analysis proband revealed a novel homozygous 5′ splice site variation in intron 3 of the CYP27A1 gene. We present a novel phenotype and genotype of CTX presenting with a syndrome of myoclonic epilepsy. This is the first PME-like presentation of CTX to the best of our knowledge. CTX may present with a PME-like clinical phenotype and should be considered as a treatable cause within the differential diagnostic evluation of syndromic epilepsies involving an atypical familial myoclonic epilepsy.

Juvenile Huntington’s disease (JHD) has an onset before 20 years of age, and is characterized by behavioural issues, epilepsy, rigidity, bradykinesia and dystonia. It contributes to 0.5–5% of all Huntington disease (HD) cases. JHD demonstrates a more rapid progression and is characterised by dystonia, as opposed to the slow progression with predominant chorea seen in adult-onset HD. Seizures are described in 38% of JHD as compared to 2% in the adult onset HD. The different types of seizures reported in JHD are generalized seizures, myoclonus, absence seizures and less commonly tonic and focal seizures with impaired awareness. JHD patients have good seizure control initially and develop drug-resistant epilepsy in the later stages of the disease which is rarely reported. Here, we report the case of a 13 -year-old boy, who initially presented with generalized tonic-clonic seizures followed by myoclonic jerks, with subsequent cognitive decline, ataxia, involuntary movements and drug resistant epilepsy mimicking a progressive myoclonus sepilepsy. His EEG changed from normal background with generalized interictal epileptiform discharges to diffuse slowing with fast activity devoid of epileptiform activity to reflect electroclinical evolution of the disease process.

Lafora Disease (LD) is a rare, fatal, late-onset, progressive form of myoclonic epilepsy, occurring in humans and dogs. Clinical manifestations of LD usually include seizures, spontaneous and reflex myoclonus with contractions of the neck and limb muscles. We studied the electroencephalogram (EEG) patterns of two beagles in whom LD was subsequently confirmed by genetic testing. In both cases, the EEG recordings, accompanied by electromyography (EMG), have shown similar uncommon patterns. The hypovoltaged background rhythm was interrupted by waxing “crescendo” polyspikes-slow wave complexes appearing 80–250 ms after the start of intermittent photic stimulation, followed by myoclonic jerks after 80–150 ms. This study highlights the value of EEG in establishing a presumptive diagnosis of LD in dogs.

Abstract Background Canine DNA-testing has become an important tool in purebred dog breeding and many breeders use genetic testing results when planning their breeding strategies. In addition, information obtained from testing of hundreds dogs in one breed gives valuable information about the breed-wide genotype frequency of disease associated allele. Lafora disease is a late onset, recessively inherited genetic disease which is diagnosed in Miniature Wirehaired Dachshunds (MWHD). It is one of the most severe forms of canine epilepsy leading to neurodegeneration and, frequently euthanasia within a few years of diagnosis. Canine Lafora disease is caused by a dodecamer repeat expansion mutation in the NHLRC1 gene and a DNA test is available to identify homozygous dogs at risk, carriers and dogs free of the mutation. Results Blood samples were collected from 733 MWHDs worldwide, mostly of UK origin, for canine Lafora disease testing. Among the tested MWHD population 7.0% were homozygous for the mutation and at risk for Lafora disease. In addition, 234 dogs were heterozygous, indicating a carrier frequency of 31.9% in the tested population. Among the tested MWHDs, the mutant allele frequency was 0.2. In addition, data from the tested dogs over 6 years (2012–2017) indicated that the frequency of the homozygous and carrier dogs has decreased from 10.4% to 2.7% and 41.5% to 25.7%, respectively among MWHDs tested. As a consequence, the frequency of dogs free of the mutation has increased from 48.1% to 71.6%. Conclusions This study provides valuable data for the MWHD community and shows that the DNA test is a useful tool for the breeders to prevent occurrence of Lafora disease in MWHDs. DNA testing has, over 6 years, helped to decrease the frequency of carriers and dogs at risk. Additionally, the DNA test can continue to be used to slowly eradicate the disease-causing mutation in the breed. However, this should be done carefully, over time, to avoid further compromising the genetic diversity of the breed. The DNA test also provides a diagnostic tool for veterinarians if they are presented with a dog that shows clinical signs associated with canine Lafora disease.

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Introduction: Berardinelli-Seip syndrome or congenital generalized lipodystrophy type 2 is a rare genetic disorder characterized by selective loss of subcutaneous adipose tissue associated with peripheral insulin resistance and its complications. Nonprogressive mental retardation, dystonia, ataxia, and pyramidal signs are commonly present, whereas epilepsy has only occasionally been observed.Case Report: We report the case of two sisters, 11 and 18 years old respectively, with an overlapping clinical phenotype compatible with Berardinelli-Seip syndrome and progressive myoclonic epilepsy. Molecular analysis identified an autosomal recessive c.1048C > t;(p(Arg350*)) pathogenic mutation of exon 8 of the BSCL2 gene, which was present in a homozygous state in both patients.Conclusions: Our paper contributes to further delineate a complex phenotype associated with BSCL2 mutation, underlining how seipin has a central and partially still unknown role that goes beyond adipose tissue metabolism, with a prominent involvement in central nervous system pathology. [ABSTRACT FROM AUTHOR]

EPM2A has been certified as a causative gene in patients with Lafora disease (LD), which is a rare autosomal recessive and severe form of progressive myoclonus epilepsy. LD classically starts in adolescence, characterized by various types of seizure with myoclonic seizure as the main type. Typically within 10 years, intractable seizure attack, rapidly progressing dementia, and a vegetative state were present. LD is particularly frequently found in Mediterranean countries. Here, we report a Chinese family with a novel compound heterozygous mutation in the EPM2A gene, characterized by recurrent vomiting, intractable epilepsy, and progressive cognitive decline. [ABSTRACT FROM AUTHOR]

De novo variants (DNVs) cause many genetic diseases. When DNVs are examined in the whole coding regions of genes in next-generation sequencing analyses, pathogenic DNVs often cluster in a specific region. One such region is the last exon and the last 50 bp of the penultimate exon, where truncating DNVs cause escape from nonsense-mediated mRNA decay [NMD(−) region]. Such variants can have dominant-negative or gain-of-function effects. Here, we first developed a resource of rates of truncating DNVs in NMD(−) regions under the null model of DNVs. Utilizing this resource, we performed enrichment analysis of truncating DNVs in NMD(−) regions in 346 developmental and epileptic encephalopathy (DEE) trios. We observed statistically significant enrichment of truncating DNVs in semaphorin 6B (SEMA6B) (p value: 2.8 × 10−8; exome-wide threshold: 2.5 × 10−6). The initial analysis of the 346 individuals and additional screening of 1,406 and 4,293 independent individuals affected by DEE and developmental disorders collectively identified four truncating DNVs in the SEMA6B NMD(−) region in five individuals who came from unrelated families (p value: 1.9 × 10−13) and consistently showed progressive myoclonic epilepsy. RNA analysis of lymphoblastoid cells established from an affected individual showed that the mutant allele escaped NMD, indicating stable production of the truncated protein. Importantly, heterozygous truncating variants in the NMD(+) region of SEMA6B are observed in general populations, and SEMA6B is most likely loss-of-function tolerant. Zebrafish expressing truncating variants in the NMD(−) region of SEMA6B orthologs displayed defective development of brain neurons and enhanced pentylenetetrazole-induced seizure behavior. In summary, we show that truncating DNVs in the final exon of SEMA6B cause progressive myoclonic epilepsy. [ABSTRACT FROM AUTHOR]

Unverricht-Lundborg disease (ULD) is an autosomal recessive progressive myoclonic epilepsy. The prevalence is highest in specific European countries and North Africa. Affected individuals have myoclonic and tonic-clonic seizures and a variable degree of ataxia and cognitive impairment. We report a native Haitian woman with ULD who was wheelchair bound due to nearly continuous myoclonic seizures exacerbated by activity and emotional distress. The seizures and their dramatic increase with volitional activity were recorded during video electroencephalography monitoring. Rational antiepileptic drug therapy controlled the seizures well enough for the patient to achieve a level of independence she had not experienced in over 25 years.

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.

Progressive myoclonic epilepsy (PME) is a syndrome characterized by development of progressive myoclonus, cognitive impairment, and other neurologic deficits. Despite major advances in medical treatment of epilepsy, some PME patients remain refractory to antiepileptic drugs. This may further accentuate cognitive impairment and deteriorate functional capacity. Corpus callosotomy (CC) is used in patients with drug-resistant epilepsy who are not candidates for either excisional epilepsy surgery or neurostimulation. We report the application of the standard complete callosotomy to control medically refractory status epilepticus in a patient with PME. A 16-year-old boy was referred to the emergency department with generalized tonic-clonic seizures. He was known to have PME since 5 years earlier, with frequent generalized seizures requiring hospitalization and reloading of the drugs. The patient was discussed by the epilepsy surgery working group, and corpus callosotomy was considered as a last resort to control the refractory status epilepticus. The patient experienced no generalized seizures during the 3-month postoperative period (Engel class IIIB). Inasmuch as surgery was the last resort to control severe disabling status epilepticus, because most of the epileptogenic discharges were originating from the parieto-occipital regions and profound cognitive impairment was present, we decided to perform a complete rather than just an anterior callosotomy. CC may be considered to prevent secondary generalized seizures as the most disabling attacks in patients with certain epilepsy syndromes. Nevertheless, the impact of palliative surgical intervention on the overall disease course of patients with an underlying diffuse pathologic state remains to be determined. [ABSTRACT FROM AUTHOR]

Sialidosis are autosomal recessive inherited disorders caused by a mutation on the NEU1 gene. In type 1 sialidosis, a “cherry-red spot” can be observed in fundoscopic examinations. In this study, a woman aged 37 years without “cherry-red spot” on ophthalmologic examination is reported to draw attention to a new phenotypic variation. Although an ophthalmologic examination was normal, for patients with consanguineous parents with progressive ataxia, drug-resistant epilepsy and myoclonus must be investigated for progressive myoclonic epilepsy and genetic analysis for sialidosis must be performed. The diagnosis is also crucial for genetic consultancy of the family.