Ommaya reservoir placement using ultrasound guidance via anterior fontanelle combined with frameless electromagnetic neuronavigation in patients with mucopolysaccharidosis type 2: Case reports and review of the literature.

Mucopolysaccharidosis type II (MPS II) results from the genetic deficiency of a lysosomal enzyme and is associated with central nervous system (CNS) dysfunction. In Japan, in addition to intravenous enzyme administration, intracerebroventricular enzyme delivery through the Ommaya reservoir has recently gained approval. Nevertheless, the ideal approach for safely implanting the reservoir into the narrow ventricles of infantile MPS II patients remains uncertain. In this report, we present two cases of successful reservoir placement in infantile MPS II patients using ultrasound guidance via the anterior fontanelle, coupled with flameless electromagnetic neuronavigation.

Transcutaneous auricular vagus nerve stimulation therapy in patients with cognitively preserved structural focal epilepsy: A case series report.

OBJECTIVE: Transcutaneous auricular vagus nerve stimulation (taVNS) was performed in two patients suffering structural focal epilepsy with preserved intellectual ability to show the feasibility of taVNS for specific patient groups. CASE PRESENTATIONS: Patient 1 was a 24-year-old woman with frontal lobe epilepsy who had weekly hyperkinetic seizures despite multiple anti-seizure medications. Patient 2 was a 27-year-old woman with parietal lobe epilepsy and focal cortical dysplasia in the vicinity of the lipoma in the corpus callosum. She experienced weekly focal-impaired awareness seizures even with anti-seizure medication. taVNS was applied to the left earlobe of both patients at 1.5 mA, 25 Hz, 250 µs pulse width, and 30 s stimulation with 30 s rest for 4 h per day. Over an 8-week baseline and 20 weeks of stimulation, the rate of reduction in seizure frequency was evaluated, along with quality-of-life using the Short-Form 36-Item Health survey. RESULTS: At baseline, we measured up to 11 and 12 focal seizures per week in Patient 1 and 2, respectively, with both patients achieving seizure freedom after 4 and 20 weeks taVNS, respectively. Patient 1 and 2 were observed for 18 and 14 months, respectively, including the clinical trial and follow-up observation period. Quality-of-life ratings increased in both patients, and no significant adverse events occurred during the study period. During the maintenance period after 20 weeks, seizures remained absent in Patient 1, and seizures remained reduced in Patient 2. CONCLUSION: Our results demonstrate that taVNS may be a promising tool for structural focal epilepsy with preserved cognitive function. A multicenter double-blind clinical trial is needed to confirm the role of taVNS as an anti-seizure tool.

Use of lacosamide for focal epilepsy in a child with kidney failure undergoing peritoneal dialysis.

BACKGROUND: Lacosamide (LCM) has become commonly used for focal onset seizures due to its high tolerability and low drug interactions. Unlike patients on hemodialysis (HD), pharmacokinetic data and dosing recommendations for patients undergoing peritoneal dialysis (PD) are scant. CASE REPORT: A 2-year-old girl with end-stage kidney disease undergoing PD suffered prolonged focal onset seizures. The patient had congenital anomalies of the kidney and urinary tract associated with branchio-oto-renal syndrome due to an EYA1 gene mutation. She also had neurological sequelae from post-resuscitation encephalopathy at the age of one month. Antiseizure medication with few drug interactions, less impact on the neurodevelopmental state and possibility of intravenous administration was preferred. LCM met those criteria and was carefully administered. Although the patient had recurrent prolonged seizures during the titration periods, LCM could be continued without any apparent side effects. The blood levels of LCM increased linearly to the optimal level. We confirmed excretion of LCM in the PD fluid. Kidney transplantation was done three months after and her seizures were well controlled. CONCLUSIONS: LCM might be a promising option for patients undergoing PD. Due to the lower removal efficacy in PD compared with in HD, close attention should be paid to possible drug excess.

Nusinersen induces detectable changes in compound motor action potential response in spinal muscular atrophy type 1 patients with severe impairment of motor function.

BACKGROUND: Most long-term affected spinal muscular atrophy (SMA) type 1 patients have severe impairment of motor function and are dependent on mechanical ventilation with tracheostomy. The efficacy and safety of nusinersen in these patients have not been established. METHODS: We retrospectively evaluated the efficacy of intrathecal nusinersen treatment in patients with SMA type 1 who continued treatment for at least 12 months. There were three patients enrolled in our study (3, 4 and 16 years of age) who had severe impairment of gross motor function without head control or the ability to roll over. All three needed mechanical ventilation with tracheostomy and tube feeding. Motor function was assessed using the Children s Hospital of Philadelphia infant test of neuromuscular disorders (CHOP-INTEND) and the caregivers' evaluations. Concurrently, we examined nerve conduction longitudinally and compared compound motor action potential (CMAP) amplitudes. RESULTS: All patients continued nusinersen administration without significant adverse events for more than three years. While CHOP-INTEND scores did not remarkably increase, according to the caregivers, all three patients had improved finger or facial muscle movements that enabled them to make their intentions understood. Some CMAPs before treatment were not identified but became traces after nusinersen administration. CONCLUSIONS: The improvement in motor function that leads to smoother communication could be a basis for continuing nusinersen treatment. Currently available motor function scorings are not efficient for assessing therapeutic interventions in SMA patients with medical care complexity. Longitudinal nerve conduction studies could be an objective indicator.

Therapeutic effects of KRM-II-81, positive allosteric modulator for α2/3 subunit containing GABAA receptors, in a mouse model of Dravet syndrome.

Introduction: Dravet syndrome (DS) is an intractable epilepsy syndrome concomitant with neurodevelopmental disorder that begins in infancy. DS is dominantly caused by mutations in the SCN1A gene, which encodes the α subunit of a voltage-gated Na channel. Pre-synaptic inhibitory dysfunction is regarded as the pathophysiological mechanism, but an effective strategy for ameliorating seizures and behavioral problems is still under development. Here, we evaluated the effects of KRM-II-81, a newly developed positive allosteric modulator for α 2/3 subunit containing GABAA receptors (α2/3-GABAAR) in a mice model of DS both in vivo and at the neuronal level. Methods: We used knock-in mice carrying a heterozygous, clinically relevant SCN1A mutation (background strain: C57BL/6 J) as a model of the DS (Scn1a WT/A1783V mice), knock-in mouse strain carrying a heterozygous, clinically relevant SCN1A mutation (A1783V). Seizure threshold and locomotor activity was evaluated by using the hyperthermia-induced seizure paradigm and open filed test, respectively. Anxiety-like behavior was assessed by avoidance of the center region in locomotor activity. We estimated a sedative effect by the total distance traveled in locomotor activity and grip strength. Inhibitory post synaptic currents (IPSCs) were recorded from a hippocampal CA1 pyramidal neuron in an acutely prepared brain slice. Results: KRM-II-81 significantly increased the seizure threshold of Scn1a WT/A1783V mice in a dose-dependent manner. A low dose of KRM-II-81 specifically improved anxiety-like behavior of Scn1a WT/A1783V mice. A sedative effect was induced by relatively high dose of KRM-II-81 in Scn1a WT/A1783V mice, the dose of which was not sedative for WT mice. KRM-II-81 potentiated IPSCs by increasing its decay time kinetics. This effect was more prominent in Scn1a WT/A1783V mice. Discussion: Higher activation of α2/3-GABAAR by KRM-II-81 suggests a compensatory modification of post synaptic inhibitory function against presynaptic inhibitory dysfunction in Scn1a WT/A1783V. The increased sensitivity for KRM-II-81 may be relevant to the distinct dose-dependent effect in each paradigm of Scn1a WT/A1783V mice. Conclusion: Selective activation for α2/3-GABAAR by KRM-II-81 could be potential therapeutic strategy for treating seizures and behavioral problems in DS.

Imbalanced expression of cation-chloride cotransporters as a potential therapeutic target in an Angelman syndrome mouse model.

Angelman syndrome is a neurodevelopmental disorder caused by loss of function of the maternally expressed UBE3A gene. Treatments for the main manifestations, including cognitive dysfunction or epilepsy, are still under development. Recently, the Cl- importer Na+-K+-Cl- cotransporter 1 (NKCC1) and the Cl- exporter K+-Cl- cotransporter 2 (KCC2) have garnered attention as therapeutic targets for many neurological disorders. Dysregulation of neuronal intracellular Cl- concentration ([Cl-]i) is generally regarded as one of the mechanisms underlying neuronal dysfunction caused by imbalanced expression of these cation-chloride cotransporters (CCCs). Here, we analyzed the regulation of [Cl-]i and the effects of bumetanide, an NKCC1 inhibitor, in Angelman syndrome models (Ube3am-/p+ mice). We observed increased NKCC1 expression and decreased KCC2 expression in the hippocampi of Ube3am-/p+ mice. The average [Cl-]i of CA1 pyramidal neurons was not significantly different but demonstrated greater variance in Ube3am-/p+ mice. Tonic GABAA receptor-mediated Cl- conductance was reduced, which may have contributed to maintaining the normal average [Cl-]i. Bumetanide administration restores cognitive dysfunction in Ube3am-/p+ mice. Seizure susceptibility was also reduced regardless of the genotype. These results suggest that an imbalanced expression of CCCs is involved in the pathophysiological mechanism of Ube3am-/p+ mice, although the average [Cl-]i is not altered. The blockage of NKCC1 may be a potential therapeutic strategy for patients with Angelman syndrome.

An integrated genetic analysis of epileptogenic brain malformed lesions.

Focal cortical dysplasia is the most common malformation during cortical development, sometimes excised by epilepsy surgery and often caused by somatic variants of the mTOR pathway genes. In this study, we performed a genetic analysis of epileptogenic brain malformed lesions from 64 patients with focal cortical dysplasia, hemimegalencephy, brain tumors, or hippocampal sclerosis. Targeted sequencing, whole-exome sequencing, and single nucleotide polymorphism microarray detected four germline and 35 somatic variants, comprising three copy number variants and 36 single nucleotide variants and indels in 37 patients. One of the somatic variants in focal cortical dysplasia type IIB was an in-frame deletion in MTOR, in which only gain-of-function missense variants have been reported. In focal cortical dysplasia type I, somatic variants of MAP2K1 and PTPN11 involved in the RAS/MAPK pathway were detected. The in-frame deletions of MTOR and MAP2K1 in this study resulted in the activation of the mTOR pathway in transiently transfected cells. In addition, the PTPN11 missense variant tended to elongate activation of the mTOR or RAS/MAPK pathway, depending on culture conditions. We demonstrate that epileptogenic brain malformed lesions except for focal cortical dysplasia type II arose from somatic variants of diverse genes but were eventually linked to the mTOR pathway.

Efficacy of sirolimus for epileptic seizures in childhood associated with focal cortical dysplasia type II.

OBJECTIVE: The efficacy of the mechanistic target of rapamycin inhibitor, sirolimus, was recently reported for patients more than 6 years of age by Kato et al. We evaluated the efficacy and safety of sirolimus in a 2-year-old patient with recurrent focal seizures with impaired consciousness after focal cortical dysplasia (FCD) type IIa resection. METHODS: The patient was a 2-year-old girl who had recurrent seizures after undergoing FCD resection at 4 months of age. The initial dose of sirolimus was 0.5 mg/day and was gradually increased using the trough blood concentration before oral administration as an index, and evaluation was performed at 92 weeks. RESULTS: The trough blood level of sirolimus was increased to 6.1 ng/mL and maintenance therapy was started at 40 weeks. Focal seizures with impairment of consciousness with tonic extension of the limbs decreased. No critically serious adverse events occurred. CONCLUSION: Sirolimus was effective against epileptic seizures from FCD type II even for a child under 5 years of age. There were no critically serious adverse events and administration could be continued.

Adrenal function during long-term ACTH therapy for patients with developmental and epileptic encephalopathy.

Some patients with developmental and epileptic encephalopathy (DEE) respond to adrenocorticotropic hormone (ACTH) therapy but relapse soon after. While long-term ACTH therapy (LT-ACTH) has been attempted for these patients, no previous studies have carefully assessed adrenal function during LT-ACTH. We evaluated the effectiveness of LT-ACTH, as well as adverse effects (AE), including their adrenal function in three DEE patients. Patients underwent a corticotropin-releasing hormone (CRH) stimulation test during LT-ACTH, and those with peak serum cortisol below 15 µg/dL were considered to be at high risk of adrenal insufficiency (AI). Two of three responded, and their life-threatening seizures with postgeneralized electroencephalogram (EEG) suppression decreased. Although no individuals had serious AE, CRH stimulation test revealed relatively weak responses, without reaching normal cortisol peak level (18 µg/dL). Hydrocortisone replacement during stress was prepared in a case with lower cortisol peak than our cutoff level. LT-ACTH could be a promising treatment option for cases of DEE that relapse soon after effective ACTH treatment. The longer duration and larger cumulative dosage in LT-ACTH than in conventional ACTH could increase the relative risk of AI. Careful evaluation with pediatric endocrinologists, including hormonal stimulation tests, might be useful for continuing this treatment safely.

Variance in the pathophysiological impact of the hemizygosity of gamma-aminobutyric acid type A receptor subunit genes between Prader-Willi syndrome and Angelman syndrome.

INTRODUCTION: Angelman syndrome (AS) and Prader-Willi syndrome (PWS) are neurodevelopmental disorders caused by loss of function of maternally expressed UBE3A and paternally expressed contiguous genes on chromosome 15q11-13, respectively. A majority of these syndromes suffer from a large deletion of the relevant chromosome (AS Del or PWS Del), which includes biallelically expressed gamma-aminobutyric acid type A receptor subunit (GABAaR) genes, while remaining individuals present without the deletion (AS non-Del or PWS non-Del). We previously reported that AS Del, but not AS non-Del individuals, show aberrantly desynchronized somatosensory-evoked magnetic fields (SEFs) and speculated that it might reflect GABAergic dysfunction due to the hemizygosity of GABAaR genes. To verify its pathophysiological impact on PWS and AS, we analyzed the SEFs of PWS individuals. METHOD: SEFs were recorded from eight PWS Del and two PWS non-Del individuals. The latency and strength of the first peak (N1m) were compared with those of AS Del/non-Del individuals and controls, most of which were obtained earlier. RESULTS: In contrast to AS, both PWS Del and PWS non-Del showed normal SEF waveforms. Desynchronized response with delayed N1m peak latency was exclusively indicated in AS Del. N1m strength was statistically higher in AS Del and AS non-Del, but not in PWS Del and PWS non-Del. CONCLUSIONS: Our results indicate that the pathophysiological impact of the hemizygosity of GABAaR genes is lower in PWS than AS. UBE3A deficiency and the hemizygosity of GABAaR genes could synergistically deteriorate neuronal function, resulting in aberrant SEFs in AS Del.

Flurothyl-induced seizure paradigm revealed higher seizure susceptibility in middle-aged Angelman syndrome mouse model.

INTRODUCTION: Epilepsy is one of the main clinical problems in Angelman syndrome (AS). Seizures typically start in early childhood then decrease or are often alleviated by young adulthood. Several studies using AS model mice showed comparable seizure susceptibility during young adulthood. In contrast, the course of epilepsy post young adulthood differs from persistently relieved to rerising among reports. To elucidate this, we evaluated the seizure susceptibility of AS model mice of two different ages. METHODS: Mice lacking maternal Ube3a gene (Ube3am-/p+) of C57BL/6 background or their littermate wild type (WT) were divided into two groups by age, 2 to 3 months (2-3 M) and 6 to 12 months (6-12 M), corresponding to adolescent to young adult aged and middle aged humans, respectively. Seizure susceptibility was evaluated by flurothyl inhalation or intraperitoneal injection of pentylenetetrazole (PTZ IP)-induced acute seizure protocol. RESULTS: In the flurothyl-induced seizure paradigm, the latency to seizure occurrence had a significant interaction with genotype and age. Post-hoc analysis revealed that the latency was significantly shorter at 6-12 M than at 2-3 M in Ube3am-/p+ mice, and in Ube3am-/p+ mice than in WT mice at 6-12 M. No significant interaction or difference was observed by PTZ IP. CONCLUSION: The flurothyl-induced seizure paradigm revealed that seizure susceptibility of Ube3am-/p+ mice increased with age, similar to clinical studies reporting the reappearance of epilepsy in older age. The flurothyl-induced seizure paradigm applied to middle-aged Ube3am-/p+ mice could be a suitable protocol for screening drugs against seizures in AS.

Short-latency somatosensory-evoked potentials demonstrate cortical dysfunction in patients with Angelman syndrome.

BACKGROUND: Angelman syndrome (AS) is neurodevelopmental disorder, causal gene of which is maternally expressed UBE3A. A majority of patients results from the large deletion of relevant chromosome which includes GABAA receptor subunit genes (GABARs) as well as UBE3A (AS Del). We previously reported aberrantly desynchronized primary somatosensory response in AS Del by using magnetoencephalography. The purpose of this study is to estimate cortical and subcortical involvement in the deficit of primary somatosensory processing in AS. METHODS: We analyzed short-latency somatosensory-evoked potentials (SSEPs) in 8 patients with AS Del. SSEPs were recorded on a 4-channel system comprising of two cortical electrodes which were placed on the frontal and centro-parietal areas. The peak and onset latency of each component were measured to compare latency and interval times. RESULTS: The first-cortical peak latency (N20, P20), and N13-N20 peak interval times were significantly prolonged in AS Del compared to healthy controls. In contrast, there was no difference in latencies between subcortical components up to N20 onset or for N11-N20 onset interval times. CONCLUSION: Highly desynchronized first-cortical SSEP components and normal latencies of subcortical components indicated cortical dysfunction rather than impairment of afferent pathways in AS Del patients, which might be attributed to GABAergic dysfunction due to loss of UBE3A function and heterozygosity of GABARs.

Reinterpretation of magnetic resonance imaging findings with magnetoencephalography can improve the accuracy of detecting epileptogenic cortical lesions.

OBJECTIVE: This study examined whether the application of magnetoencephalography (MEG) to interpret magnetic resonance imaging (MRI) findings can aid the diagnosis of intractable epilepsy caused by organic brain lesions. METHODS: This study included 51 patients with epilepsy who had MEG clusters but whose initial MRI findings were interpreted as being negative for organic lesions. Three board-certified radiologists reinterpreted the MRI findings, utilizing the MEG findings as a guide. The degree to which the reinterpretation of the imaging results identified an organic lesion was rated on a 5-point scale. RESULTS: Reinterpretation of the MRI data with MEG guidance helped detect an abnormality by at least one radiologist in 18 of the 51 patients (35.2%) with symptomatic localization-related epilepsy. A surgery was performed in 7 of the 51 patients, and histopathological analysis results identified focal cortical dysplasia in 5 patients (Ia: 1, IIa: 2, unknown: 2), hippocampal sclerosis in 1 patient, and dysplastic neurons/gliosis in 1 patient. CONCLUSIONS: The results of this study highlight the potential diagnostic applications of MEG to detect organic epileptogenic lesions, particularly when radiological visualization is difficult with MRI alone.

Efficacy of bezafibrate for preventing myopathic attacks in patients with very long-chain acyl-CoA dehydrogenase deficiency.

BACKGROUND: Very long-chain acyl-CoA dehydrogenase deficiency (VLCADD) is a mitochondrial fatty acid oxidation disorder that causes episodic attacks, such as general fatigue, hypotonia, myalgia, and rhabdomyolysis accompanied by lack of energy. As yet, there are no preventative drugs for these VLCADD-associated metabolic attacks. PATIENTS AND METHODS: We conducted an open-label, non-randomized, multi-center study into the effects of bezafibrate on five patients with VLCADD. Bezafibrate was administered for 4 years, and we analyzed the number of myopathic attacks requiring hospitalization and treatment infusions. RESULTS: The number of myopathic attacks requiring infusions of 24 h or longer significantly decreased during the study period. The patients' ability to conduct everyday activities was also improved by the treatment. CONCLUSION: Our findings show the potential long-term efficacy of bezafibrate in preventing myopathic attacks for patients with VLCADD.

Efficacy of perampanel for epileptic seizures and daily behavior in a patient with Leigh syndrome: A case report.

BACKGROUND: Leigh syndrome (LS) is a mitochondrial disorder that shows abnormal basal ganglia lesion and psychomotor regression. Although vitamins have been used for LS, we have not found any effective drug. CASE PRESENTATION: A 26-year-old man who showed psychomotor delay and short stature at the age of 1 year was diagnosed with LS according to the results of cerebrospinal fluid and high signal intensity in the bilateral striatum on T2-weighted magnetic resonance imaging. He demonstrated psychomotor delay and breathing disorders, but the progression was very slow. His symptoms suddenly worsened at the age of 24 years after acute epididymitis. He showed epileptic seizures simultaneously and his activities of daily living (ADL) significantly worsened. Several antiepileptic drugs were ineffective, but his seizures were suppressed by a low dose of perampanel and his ADL improved. CONCLUSION AND DISCUSSION: Our case showed that low-dose perampanel could be a drug for epileptic seizures and improvement of ADL in patients with LS.

Perampanel for nonepileptic myoclonus in Angelman syndrome.

BACKGROUND: Angelman syndrome (AS) is a neurodegenerative disorder caused by functional loss of the maternal ubiquitin-protein ligase 3A gene. Nonepileptic myoclonus, also described as tremulous movement, often occurs during puberty and increases in adulthood. The involuntary movement in AS has not been defined patho-physiologically and the drugs used such as levetiracetam and piracetam are not always effective. Recently, the alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionate (AMPA) receptor antagonist, perampanel (PER), was used to alleviate myoclonus in progressive myoclonus epilepsy. Herein, we tested the efficacy of PER for nonepileptic myoclonus. METHODS AND RESULTS: Four patients with AS, aged from 20 to 40 years at the beginning of treatment, were enrolled in our study. All patients reported disruption to their daily lives from the myoclonus movement. They experienced mild to moderate improvement with the starting dose of 2 mg. The dose was increased to 4 mg in one patient to achieve sufficient efficacy, while two had their dose reduced to 1 mg due to dizziness or possible exacerbation of myoclonus. The last patient continued to take the starting dose. Follow-up over 16-20 months revealed a significant reduction in the severity of nonepileptic myoclonus in all patients. CONCLUSION: Our study suggests that PER could be one of the promising drugs for nonepileptic myoclonus in AS.