Proteomic profiling of polyglucosan bodies associated with glycogenin-1 deficiency in skeletal muscle.

AIMS: Polyglucosan storage disorders represent an emerging field within neurodegenerative and neuromuscular conditions, including Lafora disease (EPM2A, EPM2B), adult polyglucosan body disease (APBD, GBE1), polyglucosan body myopathies associated with RBCK1 deficiency (PGBM1, RBCK1) or glycogenin-1 deficiency (PGBM2, GYG1). While the storage material primarily comprises glycans, this study aimed to gain deeper insights into the protein components by proteomic profiling of the storage material in glycogenin-1 deficiency. METHODS: We employed molecular genetic analyses, quantitative mass spectrometry of laser micro-dissected polyglucosan bodies and muscle homogenate, immunohistochemistry and western blot analyses in muscle tissue from a 45-year-old patient with proximal muscle weakness from late teenage years due to polyglucosan storage myopathy. RESULTS: The muscle tissue exhibited a complete absence of glycogenin-1 due to a novel homozygous deep intronic variant in GYG1 (c.7+992T>G), introducing a pseudo-exon causing frameshift and a premature stop codon. Accumulated proteins in the polyglucosan bodies constituted components of glycogen metabolism, protein quality control pathways and desmin. Muscle fibres containing polyglucosan bodies frequently exhibited depletion of normal glycogen. CONCLUSIONS: The absence of glycogenin-1, a protein important for glycogen synthesis initiation, causes storage of polyglucosan that displays accumulation of several proteins, including those essential for glycogen synthesis, sequestosome 1/p62 and desmin, mirroring findings in RBCK1 deficiency. These results suggest shared pathogenic pathways across different diseases exhibiting polyglucosan storage. Such insights have implications for therapy in these rare yet devastating and presently untreatable disorders.

Clinical outcomes among initial survivors of cryptogenic new-onset refractory status epilepsy (NORSE).

OBJECTIVE: New-onset refractory status epilepticus (NORSE) is a rare but severe clinical syndrome. Despite rigorous evaluation, the underlying cause is unknown in 30%-50% of patients and treatment strategies are largely empirical. The aim of this study was to describe clinical outcomes in a cohort of well-phenotyped, thoroughly investigated patients who survived the initial phase of cryptogenic NORSE managed in specialist centers. METHODS: Well-characterized cases of cryptogenic NORSE were identified through the EPIGEN and Critical Care EEG Monitoring Research Consortia (CCEMRC) during the period 2005-2019. Treating epileptologists reported on post-NORSE survival rates and sequelae in patients after discharge from hospital. Among survivors >6 months post-discharge, we report the rates and severity of active epilepsy, global disability, vocational, and global cognitive and mental health outcomes. We attempt to identify determinants of outcome. RESULTS: Among 48 patients who survived the acute phase of NORSE to the point of discharge from hospital, 9 had died at last follow-up, of whom 7 died within 6 months of discharge from the tertiary care center. The remaining 39 patients had high rates of active epilepsy as well as vocational, cognitive, and psychiatric comorbidities. The epilepsy was usually multifocal and typically drug resistant. Only a minority of patients had a good functional outcome. Therapeutic interventions were heterogenous during the acute phase of the illness. There was no clear relationship between the nature of treatment and clinical outcomes. SIGNIFICANCE: Among survivors of cryptogenic NORSE, longer-term outcomes in most patients were life altering and often catastrophic. Treatment remains empirical and variable. There is a pressing need to understand the etiology of cryptogenic NORSE and to develop tailored treatment strategies.

Clinical characteristics of patients with refractory non-epileptic seizures.

OBJECTIVES: This incidence of non-epileptic seizures (NES) is estimated at 1-35 per 100,000 population. While many patients achieve remission, a significant fraction of patients have a poor prognosis despite optimal interventions. This study reports on the characteristics of patients with refractory NES diagnosed and treated at a comprehensive epilepsy centre. METHODS: A retrospective review of admissions to the Epilepsy Monitoring Unit identified patients diagnosed with NES over a 6-year period. Patients with refractory NES were identified through review of medical files. A diagnosis of refractory NES was assigned when patients experienced ongoing NES at least 1 year after diagnostic video-EEG monitoring. Data pertaining to predisposing, precipitating and perpetuating factors was collected on all patients and a comparative analysis was conducted between refractory and non-refractory cases. RESULTS: 66 patients with NES were identified, 35% were deemed refractory. There was no significant difference amongst predisposing factors between the groups. Psychosocial adversity and a clear precipitant proximate to the onset of NES were significantly more common in the refractory cohort. Unemployment at time of diagnosis was a significant perpetuating factor associated with poor outcome. CONCLUSION: This study provides insight into the features associated with refractory NES and may serve to improve prognostication and management in this disabling condition.

Everolimus precision therapy for the GATOR1-related epilepsies: A case series.

BACKGROUND: Pathogenic variants in the GAP activity towards RAGs 1 (GATOR1) complex genes (DEPDC5, NPRL2, NPRL3) cause focal epilepsy through hyperactivation of the mechanistic target of rapamycin pathway. We report our experience using everolimus in patients with refractory GATOR1-related epilepsy. METHODS: We performed an open-label observational study of everolimus for drug-resistant epilepsy caused by variants in DEPDC5, NPRL2 and NPRL3. Everolimus was titrated to a target serum concentration (5-15 ng/mL). The primary outcome measure was change in mean monthly seizure frequency compared with baseline. RESULTS: Five patients were treated with everolimus. All had highly active (median baseline seizure frequency, 18/month) and refractory focal epilepsy (failed 5-16 prior anti-seizure medications). Four had DEPDC5 variants (three loss-of-function, one missense) and one had a NPRL3 splice-site variant. All patients with DEPDC5 loss-of-function variants had significantly reduced seizures (74.3%-86.1%), although one stopped everolimus after 12 months due to psychiatric symptoms. Everolimus was less effective in the patient with a DEPDC5 missense variant (43.9% seizure frequency reduction). The patient with NPRL3-related epilepsy had seizure worsening. The most common adverse event was stomatitis. CONCLUSIONS: Our study provides the first human data on the potential benefit of everolimus precision therapy for epilepsy caused by DEPDC5 loss-of-function variants. Further studies are needed to support our findings.

Extending the phenotype of posterior column ataxia with retinitis pigmentosa caused by variants in FLVCR1.

Posterior column ataxia with retinitis pigmentosa (PCARP) is a rare autosomal recessive condition due to variants in the Feline Leukemia Virus Subgroup C Cellular Receptor 1 (FLVCR1) gene which was first described in 1997. In this article, we describe a young female patient with a childhood diagnosis of retinitis pigmentosa and learning disability, presenting with progressive ataxia from her late teens. Examination revealed spastic lower limbs with absent reflexes, and reduced vibration and joint position sensation. Magnetic resonance imaging showed normal cerebellar volume and linear signal abnormality within the posterior columns of her spinal cord. Trio exome analysis confirmed two variants in FLVCR1. Our case extends the phenotype of PCARP to include learning disability and developmental delay, and highlights the importance of considering this rare condition in young adults or children with visual impairment and ataxia.

Association between social deprivation and incidence of first seizures and epilepsy: A prospective population-based cohort.

OBJECTIVE: Epidemiologic studies have investigated whether social deprivation is associated with a higher incidence of epilepsy, and results are conflicting, especially in children. The mechanisms underlying a potential association are unclear. This study examines whether there is an association between social deprivation and the incidence of first seizures (unprovoked and provoked) and new diagnosis of epilepsy by comparing incidence across an area-level measure of deprivation in a population-based cohort. METHODS: Multiple methods of case identification followed by individual case validation and classification were carried out in a defined geographical area (population 542 868) to identify all incident cases of first provoked and first unprovoked seizures and new diagnosis of epilepsy presenting during the calendar year 2017. An area-level relative deprivation index, based on 10 indicators from census data, was assigned to each patient according to registered address and categorized into quintiles from most to least deprived. RESULTS: The annual incidence of first unprovoked seizures (n = 372), first provoked seizures (n = 189), and new diagnosis of epilepsy (n = 336) was highest in the most deprived areas compared to the least deprived areas (incidence ratios of 1.79 [95% confidence interval (CI) = 1.26-2.52], 1.55 [95% CI = 1.04-2.32], and 1.83 [95% CI = 1.28-2.62], respectively). This finding was evident in both adults and children and in those with structural and unknown etiologies of epilepsy. SIGNIFICANCE: The incidence of first seizures and new diagnosis of epilepsy is associated with more social deprivation. The reason for this higher incidence is likely multifactorial.

Ataxia pancytopenia syndrome due to SAMD9L mutation presenting as demyelinating neuropathy.

Ataxia pancytopenia (ATXPC) syndrome due to gain-of-function pathogenic variants in the SAMD9L gene has been described in 38 patients to date. It is characterized by variable neurological and hematological phenotypes including ataxia, pyramidal signs, cytopenias, and hematological malignancies. Peripheral neuropathy with slowing of conduction velocities has been reported in only two affected individuals. We describe a female with childhood onset neuropathy diagnosed as Charcot-Marie-Tooth disease type 1 with onset of cerebellar ataxia in her 50s. Cerebellar, pyramidal, and neuropathic features were found on examination. Additionally, she also had conjunctival telangiectasia. Nerve conduction studies confirmed a demyelinating neuropathy. MRI brain showed cerebellar atrophy with diffuse white matter hyperintensities. OCT demonstrated global thinning of the retinal nerve fiber layer (RNFL). Full blood count has always been normal. A previously described pathogenic variant in SAMD9L [c.2956C>T p.(Arg986Cys)] was identified on whole exome sequencing. This case extends the previously described phenotype to include conjunctival telangiectasia and RNFL thinning and suggests that ATXPC syndrome should be considered in the differential for inherited demyelinating neuropathies.

Application of Recent International Epidemiological Guidelines to a Prospective Study of the Incidence of First Seizures, Newly-Diagnosed Epilepsy and Seizure Mimics in a Defined Geographic Region in Ireland.

Studies adherent to international guidelines and epilepsy classification are needed to accurately record the incidence of isolated seizures, epilepsy and seizure-mimics within a population. Because the diagnosis of epilepsy is largely made through clinical assessment by experienced physicians, seizures and epilepsy are susceptible to misdiagnosis. Previous epidemiological studies in epilepsy have not captured "seizure mimics". We therefore sought to quantify the incidence of isolated seizures, epilepsy and seizure-mimics using the International League Against Epilepsy (ILAE) classification system. In this study multiple overlapping methods of case ascertainment were applied to a defined geographic region from January 1 to March 31, 2017 to identify all patients presenting with first seizures (provoked and unprovoked), new diagnoses of epilepsy and seizure mimics. Over a 3 month period, from a population of 542,869 adults and children, 442 potential presentations were identified, and 283 met the inclusion criteria. Radiology databases were the source of the largest number of individual cases (n = 153, 54%), while electroencephalogram (EEG) databases were the source of the highest number of unique-to-source cases (those not identified elsewhere, n = 60, 21%). No single case was picked up in every method of ascertainment. Among the 283 included presentations, 38 (13%) were classed as first provoked seizures, 27 (10%) as first unprovoked seizures, 95 (34%) as new diagnosis of epilepsy and 113 (40%) as seizure mimics. Ten (3%) presentations were indeterminate. We present and apply a rigorous study protocol for investigation of the incidence of first seizures, new diagnosis of epilepsy and seizure mimics in a geographically defined region which is adherent to recently published international guidelines for epidemiologic studies and epilepsy classification. We highlight the challenges in making a diagnosis of new-onset epilepsy in patients presenting with a first seizure using the current ILAE definition of epilepsy, when epilepsy can be diagnosed in situations where the treating physician anticipates the risk of further seizures exceeds 60%.

Long-term lacosamide retention-Real-world experience at a tertiary epilepsy center in Ireland.

PURPOSE: To estimate the rate of long-term lacosamide retention among a real-world group of patients at a tertiary epilepsy center in Ireland. METHODS: One-hundred adults first prescribed lacosamide for epilepsy between January 2010 and August 2014 at Cork University Hospital were randomly selected for a retrospective analysis of medical records covering two years of subsequent epilepsy clinic follow-up to ascertain whether lacosamide was continued or withdrawn. RESULTS: Of 100 patients, (51 males, mean age 40.8years, 94 with drug-resistant epilepsy, 76 with focal epilepsy, 25 with intellectual disabilities, 34 with mental health disorders, and 42 with medical comorbidities), lacosamide was prescribed as an adjunct in 85. Lacosamide retention at 12 and 24months was 76% and 71%, respectively. Twenty-five patients stopped lacosamide due to ineffective seizure control. Adverse-effects were responsible for lacosamide discontinuation in three patients and one patient stopped lacosamide pre-pregnancy. CONCLUSION: The relatively high retention rate at two years suggests that lacosamide is generally well tolerated among people with a range of different epilepsy subtypes, intellectual disabilities, medical comorbidities, and mental health disorders, and can aid seizure control in adult patients with a range of difficult-to-treat epilepsies.

Economic analysis of an epilepsy outreach model of care in a university hospital setting.

The prevalence of epilepsy in people with intellectual disability is higher than in the general population and prevalence rates increase with increasing levels of disability. Prevalence rates of epilepsy are highest among those living in residential care. The healthcare needs of people with intellectual disability and epilepsy are complex and deserve special consideration in terms of healthcare provision and access to specialist epilepsy clinics, which are usually held in acute hospital campuses. This patient population is at risk of suboptimal care because of significant difficulties accessing specialist epilepsy care which is typically delivered in the environs of acute hospitals. In 2014, the epilepsy service at Cork University Hospital established an Epilepsy Outreach Service providing regular, ambulatory outpatient follow up at residential care facilities in Cork city and county in an effort to improve access to care, reduce the burden and expense of patient and carer travel to hospital outpatient appointments, and to provide a dedicated specialist phone service for epilepsy related queries in order to reduce emergency room visits when possible. We present the findings of an economic analysis of the outreach service model of care compared to the traditional hospital outpatient service and demonstrate significant cost savings and improved access to care with this model. Ideally these cost savings should be used to develop novel ways to enhance epilepsy care for persons with disability. We propose that this model of care can be more suitable for persons with disability living in residential care who are at risk of losing access to specialist epilepsy care.

Can syncope cause convulsive seizures in adults?

PURPOSE: Convulsive epileptic seizures triggered by transient cerebral hypoperfusion 'reflex anoxic seizures' are well-described in children but are not commonly recognized in adults. METHODS: We report a case series of 12 adults who presented acutely after generalized tonic-clonic seizures with a clear syncopal phase before the convulsion. We describe the aetiology, semiology and natural history of these events. RESULTS: Four patients (33.3%) had relevant risk factors for development of seizures/active epilepsy. Five patients (41.7%) had recurrent events prior to initial review by an epileptologist, but when anti-syncope measures were instituted there were no seizure recurrences over a median follow-up period of 34.5 (interquartile range 29.3-41.8) months. CONCLUSIONS: Syncope may be an under-recognized trigger for convulsive acute symptomatic seizures. Avoidance of syncope may be more effective than anti-seizure medications in preventing reflex anoxic seizures.

Vagus nerve stimulation in refractory idiopathic generalised epilepsy: An Irish retrospective observational study.

OBJECTIVE: Refractory idiopathic generalised epilepsy (IGE; also known as genetic generalised epilepsy) is a clinical challenge due to limited available therapeutic options. While vagus nerve stimulation (VNS) is approved as an adjunctive treatment for drug-resistant focal epilepsy, there is limited evidence supporting its efficacy for refractory IGE. METHODS: We conducted a single-centre retrospective analysis of adult IGE patients treated with VNS between January 2003 and January 2022. We analysed the efficacy, safety, tolerability, stimulation parameters and potential clinical features of VNS response in this IGE cohort. RESULTS: Twenty-three IGE patients were implanted with VNS between January 2003 and January 2022. Twenty-two patients (95.65%) were female. The median baseline seizure frequency was 30 per month (interquartile range [IQR]= 140), including generalised tonic-clonic seizures (GTCS), absences, myoclonus, and eyelid myoclonia with/without absences. The median number of baseline anti-seizure medications (ASM) was three (IQR= 2). Patients had previously failed a median of six ASM (IQR= 5). At the end of the study period, VNS therapy remained active in 17 patients (73.9%). amongst patients who continued VNS, thirteen (56.5% of the overall cohort) were considered responders (≥50% seizure frequency reduction). Amongst the clinical variables analysed, only psychiatric comorbidity correlated with poorer seizure outcomes, but was non-significant after applying the Bonferroni correction. Although 16 patients reported side-effects, none resulted in the discontinuation of VNS therapy. SIGNIFICANCE: Over half of the patients with refractory IGE experienced a positive response to VNS therapy. VNS represents a viable treatment option for patients with refractory IGE, particularly for females, when other therapeutic options have been exhausted.

Transplantation of novel human GDF5-expressing CHO cells is neuroprotective in models of Parkinson's disease.

Growth/differentiation factor 5 (GDF5) is a neurotrophic factor that promotes the survival of midbrain dopaminergic neurons in vitro and in vivo and as such is potentially useful in the treatment of Parkinson's disease (PD). This study shows that a continuous supply of GDF5, produced by transplanted GDF5-overexpressing CHO cells in vivo, has neuroprotective and neurorestorative effects on midbrain dopaminergic neurons following 6-hydroxydopamine (6-OHDA)-induced lesions of the adult rat nigrostriatal pathway. It also increases the survival and improves the function of transplanted embryonic dopaminergic neurons in the 6-OHDA-lesioned rat model of PD. This study provides the first proof-of-principle that sustained delivery of GDF5 in vivo may be useful in the treatment of PD.

Germline mosaicism in a family with MBD5 haploinsufficiency.

Haploinsufficiency of the methyl-CpG-binding domain protein 5 (MBD5) gene causes a neurodevelopmental disorder that includes intellectual disability, developmental delay, speech impairment, seizures, sleep disturbances, and behavioral difficulties. Microdeletion of 2q23.1 is the most common cause of haploinsufficiency, although MBD5 haploinsufficiency may also cause this genetic disorder. We report a family harboring a heterozygous loss-of-function variant in MBD5 (NM_018328.5:c.728delC; p.Pro243Hisfs*26), which includes three affected siblings with varying phenotypic features. Both parents were phenotypically normal but deep coverage sequencing of the parents showed germline mosaicism in the mother.

Unanticipated improvement in seizure control in drug-resistant epilepsy- real world observations.

OBJECTIVES: To determine the clinical features and anti-seizure medication (ASM) strategies associated with an unanticipated substantial improvement in seizure control in patients with drug-resistant epilepsy (DRE). METHODS: This retrospective analysis of patients attending a tertiary care epilepsy clinic between 2008 and 2017 identified all patients with active DRE (at least 1 seizure per month for 6 months, despite treatment with 2 different ASMs). All treatment interventions were recorded from when DRE was first identified to the end of the study. The primary end points were seizure freedom or meaningful reduction in seizure frequency (greater than 75 %) sustained for at least 12 months after a treatment intervention. RESULTS: Three hundred and twenty-two patients were included in the analysis. Overall, 10 % became seizure free following ASM adjustment and an additional 10 % had a greater than 75 % improvement in seizure control (median follow-up, 4 years). An ASM introduction was ten times more likely than an ASM dose increase to improve seizure control. Combined focal and generalized epilepsy, intellectual disability and prior treatment with more than 5 ASMs were more frequently observed in those with continued pharmacoresistance. ASM responders were more likely to have primary generalized epilepsy. Rational polytherapy (combining ASMs with different mechanisms of action) was almost ubiquitous amongst ASMs responders (95 % taking at least 2 drugs with different mechanistic targets). Of the ASM additions that heralded improved seizure control, 85 % were maintained at submaximal doses. CONCLUSIONS: This retrospective analysis of a large number of 'real-world' patients provides evidence to persist with ASM trials in DRE. Early rotation of ASMs if a clinical response is not observed at a substantial dose and rational ASM polytherapy may yield better clinical outcomes in patients with DRE, although a prospective study would need to be conducted to validate these findings.

Causes and classification of first unprovoked seizures and newly-diagnosed epilepsy in a defined geographical area- an all-comers analysis.

PURPOSE: The ILAE recently updated the operational definition of epilepsy and the classifications of seizures and epilepsy incorporating aetiology into the classification framework. To date, these classifications have not been applied in any whole population incidence study. METHODS: Multiple overlapping methods of case identification were applied to a defined geographical area (population 542,868 adults and children) to identify all first unprovoked seizures and new diagnosis of epilepsy presenting during the calendar year 2017. The 2017 ILAE classification frameworks were applied. Incidence was age-standardised to the 2013 Standard European Population. RESULTS: The annual incidence per 100,000 population was 44 for focal epilepsy, 6.8 for generalized epilepsy and 10.9 for unclassified epilepsy (age standardized 56, 6.9 and 11.4, respectively). Focal epilepsy was diagnosed in all age groups, though incidence increased in those ≥55 years of age. Primary generalised epilepsy accounted for 10% (n = 32) of newly diagnosed epilepsy. The most frequently diagnosed aetiology was structural (54%, n = 182). In 30% (n = 102) of newly diagnosed epilepsy, aetiology was not established. CONCLUSION: We report on the causes of incident first unprovoked seizures and epilepsy in accordance with recently updated ILAE definitions and classification systems employing standard diagnostic investigations. We report a higher proportion of structural aetiology than previous studies, which may reflect incorporation of imaging in aetiology classification. Despite improved access to diagnostic testing, aetiology of a large fraction of first seizures and newly diagnosed epilepsy remains unknown.

Incidence of first seizures, epilepsy, and seizure mimics in a geographically defined area.

OBJECTIVE: To determine the incidence of first seizures, epilepsy, and seizure mimics in a geographically defined area using the updated 2014 International League Against Epilepsy (ILAE) definition, which allows an epilepsy diagnosis after a single seizure when the risk of further seizures over the next 10 years is ≈60% or greater. This replaced the 1993 definition by which epilepsy was diagnosed when a person had ≥2 seizures separated by 24 hours. METHODS: Using multiple overlapping methods of case ascertainment followed by individual case classification by an epileptologist, we identified all first seizures, new diagnosis of epilepsy, and seizure mimics occurring in a defined geographic area (population 542,868) from January 1, 2017, to December 31, 2017. Incidence was age standardized to the Standard European Population. We compared incidence rates using the 2014 and 1993 ILAE definitions. RESULTS: When the 2014 ILAE definition of epilepsy was applied, the incidence of new diagnosis of epilepsy was 62 per 100,000 (age standardized 74) compared to 41 per 100,000 (age standardized 48) when the 1993 definition was applied, and the difference was more pronounced at older ages. The incidence of all first seizures and of seizure mimics was 102 per 100,000 (age standardized 123) and 94 per 100,000 (age standardized 111), respectively. The most frequently encountered seizure mimic was syncope. CONCLUSION: Application of the 2014 ILAE definition of epilepsy resulted in a higher incidence of new diagnosis of epilepsy compared to the 1993 definition. The incidence of seizure mimics almost equals that of all first seizures. Seizures, epilepsy, and seizure mimics represent a significant burden to health care systems.

De-novo mutations in patients with chronic ultra-refractory epilepsy with onset after age five years.

We set out to investigate whether a de-novo paradigm could explain genetic causes of chronic ultra-refractory epilepsy, with onset later than the typical age for the epileptic encephalopathies. We performed exome sequencing on nine adult patients with MRI-negative epilepsy and no preceding intellectual disability. All had an onset of seizures after five years old and had chronic ultra-refractory epilepsy defined here as having failed more than six anti-epileptic drugs and currently experiencing ≥4 disabling seizures per month. Parents were sequenced to identify de-novo mutations and these were assessed for likelihood of pathogenicity based on the American College of Medical Genetics and Genomics (ACMG) criteria. We confirmed the presence of functional and predicted-damaging de-novo mutations in 3/9 patients. One of these pathogenic de-novo mutations, in DNM1L, was previously reported in a patient with severe epilepsy and chronic pharmacoresistance adding to the evidence for DNM1L as an epilepsy gene. Exome sequencing is a successful strategy for identifying de-novo mutations in paediatric epileptic encephalopathies and rare neurological disorders. Our study demonstrates the potential benefit of considering ultra-refractory epilepsy patients with later onset for genetic testing. Identifying genetic mutations underpinning severe epilepsy of unknown aetiology may provide new insight into the underlying biology and offers the potential for therapeutic intervention in the form of precision medicine in older patients.