Impact of general practice / family medicine training on Japanese junior residents:a descriptive study.

BACKGROUND: Despite international recognition of the impact of general practice / family medicine training on postgraduate training outcomes, there have been few reports from Japan. METHODS: Junior residents who participated in community medicine training for one month between 2019 and 2022 were enrolled in the study. The settings were five medical institutions (one hospital and four clinics) that had full-time family doctors. The junior residents were assigned to one of these institutions. The training content mainly consisted of general ambulatory care, home medical care, community-based care, and reflection. The junior residents evaluated themselves at the beginning and end of their training, and the family doctors evaluated the junior residents at the end. The evaluation items were 36 items in 10 areas, based on the objectives outlined in the Guidelines for Residency Training - 2020 Edition, and were rated on a 10-point Likert scale. In the statistical analysis, Wilcoxon signed rank test of two related groups was performed to analyze changes between pre and post self-evaluation, and the effect size r was calculated. RESULTS: Ninety-one junior residents completed the study. Their self-evaluations showed statistically significant increases in all 36 items. The effect size was large in 33 items. The family doctors' evaluation was 8-9 points for all 36 items. CONCLUSION: General practice / family medicine training may greatly contribute to the acquisition of various required clinical abilities in postgraduate training even in Japan.

Mutation in the STXBP1 Gene Associated with Early Onset West Syndrome: A Case Report and Literature Review.

Syntaxin-binding protein1 (STXBP1) is a member of the Sec1/Munc18-1 protein family, which comprises important regulators of the secretory and synaptic vesicle fusion machinery underlying hormonal and neuronal transmission, respectively. STXBP1 pathogenic variants are associated with multiple neurological disorders. Herein, we present the case of a Japanese girl with a mutation in the STXBP1 gene, who was born at 40 weeks without neonatal asphyxia. At 15 days old, she developed epilepsy and generalized seizures. Around 88 days old, she presented with a series of nodding spasms, with the seizure frequency gradually increasing. Interictal EEG indicated hypsarrhythmia and she presented with developmental regression. At 1.5 years old, genetic testing was performed and mutational analysis revealed an STXBP1 gene mutation (c.875G > A: p.Arg292His). Accordingly, she was diagnosed with developmental and epileptic encephalopathy, presenting West syndrome's clinical characteristics caused by the STXBP1 gene mutation. Although drug treatment has reduced the frequency of epileptic seizures, her development has remained regressive. The relationship between the location and type of genetic abnormality and the phenotype remains unclear. Future studies should investigate the genotype−phenotype correlation and the underlying pathophysiology to elucidate the causal relationships among the multiple phenotype-determining factors.

CUX2 deficiency causes facilitation of excitatory synaptic transmission onto hippocampus and increased seizure susceptibility to kainate.

CUX2 gene encodes a transcription factor that controls neuronal proliferation, dendrite branching and synapse formation, locating at the epilepsy-associated chromosomal region 12q24 that we previously identified by a genome-wide association study (GWAS) in Japanese population. A CUX2 recurrent de novo variant p.E590K has been described in patients with rare epileptic encephalopathies and the gene is a candidate for the locus, however the mutation may not be enough to generate the genome-wide significance in the GWAS and whether CUX2 variants appear in other types of epilepsies and physiopathological mechanisms are remained to be investigated. Here in this study, we conducted targeted sequencings of CUX2, a paralog CUX1 and its short isoform CASP harboring a unique C-terminus on 271 Japanese patients with a variety of epilepsies, and found that multiple CUX2 missense variants, other than the p.E590K, and some CASP variants including a deletion, predominantly appeared in patients with temporal lobe epilepsy (TLE). The CUX2 variants showed abnormal localization in human cell culture analysis. While wild-type CUX2 enhances dendritic arborization in fly neurons, the effect was compromised by some of the variants. Cux2- and Casp-specific knockout mice both showed high susceptibility to kainate, increased excitatory cell number in the entorhinal cortex, and significant enhancement in glutamatergic synaptic transmission to the hippocampus. CASP and CUX2 proteins physiologically bound to each other and co-expressed in excitatory neurons in brain regions including the entorhinal cortex. These results suggest that CUX2 and CASP variants contribute to the TLE pathology through a facilitation of excitatory synaptic transmission from entorhinal cortex to hippocampus.

Relationship Between Sensory Processing and Autism Spectrum Disorder-Like Behaviors in Prader-Willi Syndrome.

The relationship between sensory processing and ASD-like and associated behaviors in patients with Prader-Willi Syndrome (PWS) remains relatively unexplored. Examining this relationship, 51 adults with PWS were administered the Pervasive Developmental Disorders Autism Society Japan Rating Scale (PARS), Short Sensory Profile (SSP-J), Food-Related Problem Questionnaire (FRPQ), and Aberrant Behavior Checklist (ABC-J). Based on SSP-J z-scores, participants were classified into three severity groups. Analysis of variance was performed to compare the behavioral scores of these three groups. Statistically significant group differences were observed in PARS (p = .006, ηp2 = .194) and ABC-J (p = .006, ηp2 = .193) scores. Our findings suggest that the level of sensory processing may predict ASD-like and aberrant behaviors in adults with PWS, implying the importance of a proper assessment for early intervention.

Burden of seizures and comorbidities in patients with epilepsy: a survey based on the tertiary hospital-based Epilepsy Syndrome Registry in Japan.

OBJECTIVE: To examine the current medical and psychosocial status of patients with epilepsy, aiming to facilitate appropriate application of the Intractable/Rare Diseases Act of Japan. METHODS: By analysing the cross-sectional data of patients registered in the tertiary hospital-based Epilepsy Syndrome Registry of Japan, we investigated the proportion of patients who met the severity criteria as defined by the Act (seizure frequency of at least once a month, or presence of intellectual/neurological/psychiatric symptoms, or both) and whether there are candidate syndrome/diseases to be added to the existing list in the Act. RESULTS: In total, 2,209 patients were registered. After excluding self-limited/idiopathic epilepsies, 1,851 of 2,110 patients (87.7%) met the severity criteria. The patients were classified into eight main epilepsy syndromes (594 patients), 20 groups based on aetiology (1,078 patients), and three groups without known aetiology (427 patients). Most of the groups classified by syndrome or aetiology had high proportions of patients satisfying the severity criteria (>90%), but some groups had relatively low proportions (<80%) resulting from favourable outcome of surgical therapy. Several small groups with known syndrome/aetiology await detailed analysis based on a sufficiently large enough number of patients registered, some of whom may potentially be added to the list of the Act. SIGNIFICANCE: The registry provides data to examine the usefulness of the severity criteria and list of diseases that are operationally defined by the Act. Most epilepsy patients with various syndromes/diseases and aetiology groups are covered by the Act but some are not, and the list of designated syndromes/diseases should be complemented by further amendments, as suggested by future research.

The effectiveness of intravenous benzodiazepine for status epilepticus in Dravet syndrome.

PURPOSE: We aimed to evaluate choice and efficacy of intravenous antiepileptic drugs (AEDs) for status epilepticus (SE) in Dravet syndrome and to find predictable clinical features demonstrating the effectiveness of benzodiazepine (BZD) for SE. METHODS: We retrospectively investigated the medical records in patients with Dravet syndrome and evaluated the effectiveness rate of intravenous AEDs and the rate of adverse effects. To find the clinical features of BZD-effective SE, we divided the SE episodes into the following two groups: BZD effective group and BZD non-effective group. The choice of treatment was dependent on physicians' discretion according to the protocol for SE in our institution. RESULTS: Sixty-eight SE episodes in 10 patients were assessed. The median age at SE was 31 months. Of 68 episodes, 42 episodes (61.8%) were in the BZD effective group and 26 (38.2%) in the BZD non-effective group. There were no significant differences in clinical features. In the BZD non-effective group, the effective rates of continuous midazolam, phenobarbital, phenytoin/fosphenytoin were 9/9 episodes (100%), 14/17 (82.4%), and 2/5 (40.0%), respectively. Adverse effects were identified in 19/68 episodes (27.9%), including 11/42 episodes in the BZD effective group and 8/26 in the BZD non-effective group, which was no statistical difference between the two groups. Respiratory suppression was found in all 19 episodes and the incidence of endotracheal intubation in the BZD non-effective group (15.4%) was higher than that in the BZD effective group (2.4%) (p = 0.046). CONCLUSION: BZD may be used as first choice, and phenobarbital prior to continuous midazolam as second choice for SE with Dravet syndrome. There might be no predictable clinical features showing that BZD will be effective.

Neuroanatomical considerations for optimizing thalamic deep brain stimulation in Tourette syndrome.

OBJECTIVE: Deep brain stimulation (DBS) of the centromedian thalamic nucleus has been reportedly used to treat severe Tourette syndrome, yielding promising outcomes. However, it remains unclear how DBS electrode position and stimulation parameters modulate the specific area and related networks. The authors aimed to evaluate the relationships between the anatomical location of stimulation fields and clinical responses, including therapeutic and side effects. METHODS: The authors collected data from 8 patients with Tourette syndrome who were treated with DBS. The authors selected the active contact following threshold tests of acute side effects and gradually increased the stimulation intensity within the therapeutic window such that acute and chronic side effects could be avoided at each programming session. The patients were carefully interviewed, and stimulation-induced side effects were recorded. Clinical outcomes were evaluated using the Yale Global Tic Severity Scale, the Yale-Brown Obsessive-Compulsive Scale, and the Hamilton Depression Rating Scale. The DBS lead location was evaluated in the normalized brain space by using a 3D atlas. The volume of tissue activated was determined, and the associated normative connective analyses were performed to link the stimulation field with the therapeutic and side effects. RESULTS: The mean follow-up period was 10.9 ± 3.9 months. All clinical scales showed significant improvement. Whereas the volume of tissue activated associated with therapeutic effects covers the centromedian and ventrolateral nuclei and showed an association with motor networks, those associated with paresthesia and dizziness were associated with stimulation of the ventralis caudalis and red nucleus, respectively. Depressed mood was associated with the spread of stimulation current to the mediodorsal nucleus and showed an association with limbic networks. CONCLUSIONS: This study addresses the importance of accurate implantation of DBS electrodes for obtaining standardized clinical outcomes and suggests that meticulous programming with careful monitoring of clinical symptoms may improve outcomes.

Current medico-psycho-social conditions of patients with West syndrome in Japan.

OBJECTIVE: To unveil current medical and psychosocial conditions of patients with West syndrome in Japan. METHODS: A cross-sectional analysis was performed in patients with West syndrome registered in the Rare Epilepsy Syndrome Registry (RES-R) of Japan. Furthermore, new-onset patients registered in the RES-R were observed prospectively and their outcomes after one and two years of follow-up were compared with data at onset. RESULTS: For the cross-sectional study, 303 patients with West syndrome were included. Seizures (such as spasms, tonic seizures and focal seizures) occurred daily in 69.3% of the patients at registration. Seizure frequency of less than one per year was observed in cases of unknown etiology (22.6%), genetic etiology (23.8%) and malformation of cortical development (MCD; 19.1%). Neurological findings were absent in 37.0%, but a high rate of abnormality was seen in patients with Aicardi syndrome, hypoxic-ischemic encephalopathy (HIE), genetic etiology and MCD other than focal cortical dysplasia, accompanied by a >50% rate of bedridden patients. Abnormal EEG was found in 96.7%, and CT/MRI was abnormal in 62.7%. Treatments included antiepileptic drug therapy (94.3%), hormonal therapy (72.6%), diet therapy (8.3%) and surgery (15.8%). Intellectual/developmental delay was present in 88.4%, and was more severe in patients with Aicardi syndrome, genetic etiology and HIE. Autism spectrum disorder was found in 13.5%. For the longitudinal study, 27 new-onset West syndrome patients were included. The follow-up study revealed improved seizure status after two years in 66.7%, but worsened developmental status in 55.6%, with overall improvement in 51.9%. SIGNIFICANCE: The study reveals the challenging neurological, physical and developmental aspects, as well as intractable seizures, in patients with West syndrome. More than a half of the children showed developmental delay after onset, even though seizures were reduced during the course of the disease.

Comparative characterization of PCDH19 missense and truncating variants in PCDH19-related epilepsy.

Missense and truncating variants in protocadherin 19 (PCDH19) cause PCDH19-related epilepsy. In this study, we aimed to investigate variations in distributional characteristics and the clinical implications of variant type in PCDH19-related epilepsy. We comprehensively collected PCDH19 missense and truncating variants from the literature and by sequencing six exons and intron-exon boundaries of PCDH19 in our cohort. We investigated the distribution of each type of variant using the cumulative distribution function and tested for associations between variant types and phenotypes. The distribution of missense variants in patients was clearly different from that of healthy individuals and was uniform throughout the extracellular cadherin (EC) domain, which consisted of six highly conserved domains. Truncating variants showed two types of distributions: (1) located from EC domain 1 to EC domain 4, and (2) located from EC domain 5 to the cytoplasmic domain. Furthermore, we also found that later onset seizures and milder intellectual disability occurred in patients with truncating variants located from EC domain 5 to the cytoplasmic domain compared with those of patients with other variants. Our findings provide the first evidence of two types of truncating variants in the PCDH19 gene with regard to distribution and the resulting clinical phenotype.

Application of induced pluripotent stem cells in epilepsy.

Epilepsy is among the most common neurological disorders, affecting approximately 50 million people worldwide. Importantly, epilepsy is genetically and etiologically heterogenous, but several epilepsy types exhibit similar clinical presentations. Epilepsy-associated genes are being identified. However, the molecular pathomechanisms remain largely unknown. Approximately one-third of epilepsy is refractory to multiple conventional anti-epileptic drugs (AEDs). Induced pluripotent stem cells (iPSCs) provide an excellent tool to study the pathomechanisms underlying epilepsy and to develop novel treatments. Indeed, disease-specific iPSCs have been established for several genetic epilepsies. In particular, the molecular mechanisms underlying certain developmental and epileptic encephalopathies, such as Dravet syndrome, have been revealed. Modeling epilepsy with iPSCs enables new drug development based on the elucidated pathomechanisms. This can also be used to evaluate conventional AEDs and drug repurposing. Furthermore, transplanting neuronal cells derived from iPSCs into the brain has great potential to treat refractory epilepsies. Recent advances in iPSC technology have enabled the generation of neuronal organoids, or "mini brains." These organoids demonstrate electrophysiological activities similar to those of the brain and have the potential for extensive epilepsy research opportunities. Thus, the application of iPSCs in epilepsy provides insight into novel treatments based on the molecular pathomechanisms of epilepsy. In this review, we comprehensively discuss the studies conducted on iPSCs established for genetic epilepsy or epilepsies without major structural dysmorphic features.

Coffin-Siris syndrome with bilateral macular dysplasia caused by a novel exonic deletion in ARID1B.

Coffin-Siris syndrome (CSS) is a congenital anomaly syndrome characterized by developmental delay, coarse facial features, and hypoplasia of the fifth digit's nail or phalanges. Herein, we report a case of the 8-year-old female patient who showed developmental delay associated with dysplasia in the macular and large toe area. Comprehensive genomic analysis showed no possible candidate variants, but the subsequent genomic copy number analysis revealed a novel exonic deletion in the coding region of AT-rich interactive domain-containing protein 1B (ARID1B), a gene responsible for CSS. Genomic copy number analysis can aid in diagnosing CSS by confirming undiagnosed exonic deletions in ARID1B. Furthermore, this is the first report of CSS associated with bilateral macular dysplasia.

Glucose transporter type 1 deficiency syndrome associated with autoantibodies to glutamate receptors.

BACKGROUND: The clinical spectrum of glucose transporter type 1 deficiency syndrome (GLUT1DS) has broadened, with increasing recognition of a milder phenotype. Antibodies targeting the subunits of glutamate receptors (GluRs), including GluN1, GluN2B, and GluD2, have been detected in various neurological disorders. Anti-GluD2 antibodies in particular may be associated with cerebellar symptoms. CASE REPORT: A 3-year-5-month-old boy with normal development exhibited myoclonus refractory to antiepileptic drugs from one year ago. He developed tremor and ataxia. Cerebrospinal fluid (CSF) revealed fasting-state glucose 50 mg/dl (CSF/blood glucose ratio of 0.50). Single photon emission computed tomography with 123I-iodoamphetamine revealed hypoperfusion in the cerebellum. At age 4 years and 5 months, treatment with intravenous methylprednisolone (IVMP) relieved his symptoms and improved the cerebellar hypoperfusion. However, his symptoms reappeared at age 5 years and 1 month. Treatment with IVMP was repeated, resulting in transient disappearance of symptoms. At age 6 years and 9 months, he was diagnosed with GLUT1DS by genetic analysis, and treatment with modified Atkins diet was started with efficacy. Levels of anti-GluN1, -GluN2B, and -GluD2 antibodies in the serum and CSF were measured 4 times. All antibodies in the CSF were elevated over 2 standard deviations above controls, and the levels fluctuated along with the severity of his symptoms. The level of anti-GluD2 antibodies in CSF declined to the normal range only after starting the modified Atkins diet. CONCLUSION: Treatment with IVMP transiently improved this patient's symptoms. Levels of anti-GluR antibodies may be associated with symptom severity.

Epidemiological changes of acute encephalopathy in Japan based on national surveillance for 2014-2017.

BACKGROUND: We previously reported the nationwide, epidemiological data of acute encephalopathy in Japan during 2007-2010. Here we conducted the second national survey of acute encephalopathy during 2014-2017, and compared the results between the two studies to elucidate the trends in the seven years' interval as well as the influence of changes in pediatric viral infections and guidelines for acute encephalopathy in Japan. METHODS: The Research Committee on Acute Encephalopathy supported by the Japanese Government sent a questionnaire to 507 hospitals throughout Japan, and collected the responses by mail. RESULTS: A total of 1115 cases from 267 hospitals reportedly had acute encephalopathy during April 2014-June 2017. In this study, the age at onset was younger, the ratios of recently established syndromes, such as acute encephalopathy with biphasic seizures and late reduced diffusion (AESD) and clinically mild encephalitis/encephalopathy with a reversible splenial lesion (MERS), were higher, and the ratio of influenza-associated encephalopathy was lower, than in the previous study. The age at onset of influenza-associated encephalopathy was lower, and that of HHV-6/7-associated encephalopathy higher, compared to the first survey. The outcomes of entire acute encephalopathy remained unchanged. CONCLUSION: Some of these changes reflected the recent trends of viral infectious diseases including 2009 influenza pandemic, and others the standardization of the diagnosis of acute encephalopathy in Japan.

Case-control association study of rare nonsynonymous variants of SCN1A and KCNQ2 in acute encephalopathy with biphasic seizures and late reduced diffusion.

PURPOSE: Acute encephalopathy with biphasic seizures and late reduced diffusion (AESD) is characterized by prolonged febrile seizures at onset and subsequent damage to the cerebral cortex of infants and children. The pathogenesis is suspected to be excitotoxicity leading to neuronal death. SCN1A and KCNQ2 are causative genes of genetic epilepsy including Dravet syndrome and Ohtahara syndrome. Here we conducted a case-control rare-variant association study of the two genes in AESD. METHODS: The coding regions of SCN1A and KCNQ2 were sequenced by the Sanger method for 175 and 111 patients, respectively, with AESD. As control subjects, we used genetic data from 3554 subjects provided by the Integrative Japanese Genome Variation Database (iJGVD). Then we performed a case-control association study of rare missense and splice region variants (minor allele frequency < 0.005) of each gene with AESD using Weighted Sum Statistics (WSS) and Sequence Kernel Association Test (SKAT). RESULTS: SCN1A rare variants had a significant association with AESD after correction for multiple tests (WSS, permutated p value 4.00 × 10-3: SKAT, p value 2.51 × 10-4). The association was more significant when we focused on deleterious variants (WSS, permutated p = 9.00 × 10-4; SKAT, p = 4.99 × 10-5). Although KCNQ2 rare nonsynonymous variants tended to be more frequent in patients than in controls, there was no significant difference. CONCLUSION: Our study provided statistical evidence of an association between SCN1A and AESD for the first time, and established SCN1A as one of the susceptibility genes for AESD.

Clinical features of early myoclonic encephalopathy caused by a CDKL5 mutation.

BACKGROUND: CDKL5 deficiency is caused by mutations in the cyclin-dependent kinase-like 5 (CDKL5) gene and clinically manifests often in females as drug-resistant intractable epilepsy and severe psychomotor retardation. CASE REPORT: We report the case of a girl with a CDKL5 mutation born at 39 weeks without neonatal asphyxia. She developed epilepsy at age 1 month with myoclonus of the face and limbs, and non-rhythmic and irregular opsoclonus. She developed tonic seizures and epileptic spasms at 6 months of age and was diagnosed with symptomatic West syndrome and underwent adrenocorticotropic hormone therapy but her seizures were refractory. At the age of 4, she was introduced to our hospital and development was at 2 months of age. We diagnosed her with early myoclonic encephalopathy (EME) due to the remaining suppression-burst pattern observed on an electroencephalogram and her symptoms since onset were mainly myoclonus. At 14 years of age, mutational analysis revealed a CDKL5 mutation (c.380A > G:p.His127Arg). She was diagnosed with epileptic encephalopathy exhibiting clinical features of early myoclonic epilepsy caused by CDKL5 deficiency. CONCLUSIONS: Early onset epilepsy with severe psychomotor retardation without a known etiology may be caused by a mutation in CDKL5. More research investigating a genotype-phenotype correlation of CDKL5 mutations is necessary because clinical severity may be associated with the location and type of mutations.

Copy number variation analysis in 83 children with early-onset developmental and epileptic encephalopathy after targeted resequencing of a 109-epilepsy gene panel.

Early-onset developmental and epileptic encephalopathy (DEE) is a group of devastating disorders that appear during the neonatal and infantile periods. Despite great progress in the discovery of genes leading to early-onset DEE, many cases with unexplained etiology remain. Furthermore, to date, the association of copy number variations (CNVs) with early-onset DEE has seldom been addressed. Here, we investigated the contribution of CNVs to epilepsy in a cohort of Japanese children with a variety of early-onset DEEs. Single nucleotide polymorphism (SNP) array analysis was performed for 83 cases that were previously negative for pathogenic single nucleotide variants (SNVs) in 109 genes known or suspected to cause epileptic seizures. Rare CNVs were detected in a total of 12 cases (14.4%), of which three cases (3.6%) involved clearly pathogenic CNVs and nine cases (10.8%) were CNVs of uncertain significance. The three pathogenic CNVs included two de novo heterozygous deletions involving known epileptic encephalopathy genes, such as GABRG2 and PCDH19, and one maternally inherited duplication encompassing MECP2. Our findings indicate rare CNVs are also relevant for the diagnosis of early-onset DEEs, highlighting the importance of not relying only on the investigation of SNVs/small indels at the risk of missing large deletions and duplications.

Characteristics of KCNQ2 variants causing either benign neonatal epilepsy or developmental and epileptic encephalopathy.

OBJECTIVE: Pathogenic variants of KCNQ2, which encode a potassium channel subunit, cause either benign (familial) neonatal epilepsy-B(F)NE)-or KCNQ2 encephalopathy (KCNQ2 DEE). We examined the characteristics of KCNQ2 variants. METHODS: KCNQ2 pathogenic variants were collected from in-house data and two large disease databases with their clinical phenotypes. Nonpathogenic KCNQ2 variants were collected from the Genome Aggregation Database (gnomAD). Pathogenicity of all variants was reevaluated with clinical information to exclude irrelevant variants. The cumulative distribution plots of B(F)NE, KCNQ2 DEE, and gnomAD KCNQ2 variants were compared. Several algorithms predicting genetic variant pathogenicity were evaluated. RESULTS: A total of 259 individuals or pedigrees with 216 different pathogenic KCNQ2 variants and 2967 individuals with 247 different nonpathogenic variants were deemed eligible for the study. Compared to the distribution of nonpathogenic variants, B(F)NE and KCNQ2 DEE missense variants occurred in five and three specific KCNQ2 regions, respectively. Comparison between B(F)NE and KCNQ2 DEE sets showed that B(F)NE missense variants frequently localized to the intracellular domain between S2 and S3, whereas those of KCNQ2 DEE were more frequent in S6, and its adjacent pore domain, as well as in the intracellular domain between S6 and helix A. The scores of Protein Variation Effect Analyzer (PROVEAN) and Percent Accepted Mutation (PAM) 30 prediction algorithms were associated with phenotypes of the variant loci. SIGNIFICANCE: Missense variants in the intracellular domain between S2 and S3 are likely to cause B(F)NE, whereas those in S6 and its adjacent regions are more likely to cause KCNQ2 DEE. With such regional specificities of variants, PAM30 is a helpful tool to examine the possibility that a novel KCNQ2 variant is a B(F)NE or KCNQ2 DEE variant in genetic analysis.

PRRT2 mutations in Japanese patients with benign infantile epilepsy and paroxysmal kinesigenic dyskinesia.

PURPOSE: This study was performed to clarify the clinical features of Japanese patients with PRRT2 mutations. METHODS: The PRRT2 gene was analyzed in 135 patients with benign infantile epilepsy (BIE) or paroxysmal kinesigenic dyskinesia (PKD) using a direct sequencing method: 92 patients had BIE alone, 25 had both BIE and PKD, and 18 had PKD alone. Of the cases, 105 were familial, and 30 were sporadic. Clinical information was collected using a structured questionnaire. RESULTS: PRRT2 mutations were identified in 104 patients. Among the familial cases, PRRT2 mutations were found in at least one individual in 21 of 28 families with BIE alone, in 26 of 27 families with infantile convulsions and choreoathetosis, and in 2 of 3 families with PKD alone. Among the sporadic cases, PRRT2 mutations were observed in 7 of 25 patients with BIE alone, in 1 of 1 patient with BIE and PKD, and in 3 of 4 patients with PKD alone. The c.649dupC mutation was the most frequent, followed by the c.981C > G mutation. Among the patients with epilepsy, the median age at BIE onset was 5 months, the median age at the last seizure was 6 months, and the median number of seizures was 5. CONCLUSION: PRRT2 mutations were found in 68% of Japanese probands with BIE or PKD. The phenotypes of BIE associated with PRRT2 mutations were consistent with those of BIE diagnosed clinically.

Heart rate variability in a patient with alternating hemiplegia.

Alternating hemiplegia of childhood (AHC) is a rare disorder characterized by repetitive episodes of transient hemiplegia. Although autonomic nervous system dysfunction is believed to be associated with AHC, there are no reports of heart rate variability (HRV) in patients with AHC. In the current study, we analyzed HRV in a 20-year-old female with this disorder. The frequency of paralytic attacks have decreased since the patient was a teenager, compared to when she was < ten years old; however, as a 20-year-old, she still experiences paralytic attacks several times per month to more than ten times per month. Thus far, she has only suffered paralytic attacks and no epileptic seizures. Using Sanger sequencing, Gly947Arg (2839G>A) in the sodium-potassium (Na+/K+)-ATPaseα3 subunit gene (ATP1A3) was confirmed from her blood sample. An elevated heart rate lasting one to two minutes and sometimes longer, was primarily observed at night while the patient was sleeping. Large fluctuations in HRV, including low- and high- frequency components, were primarily observed while the patient was sleeping but suppressed during paralytic attacks. These results confirm the presence of an autonomic nervous system disorder in AHC. Because large variation of the autonomic nervous function was observed at night, the pathophysiological function should be investigated for 24 hours.