Publications by authors named "Rie Miyata"

40 Publications

Whole genome sequencing of 45 Japanese patients with intellectual disability.

Am J Med Genet A 2021 05 24;185(5):1468-1480. Epub 2021 Feb 24.

Department of Mental Retardation and Birth Defect Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Tokyo, Japan.

Intellectual disability (ID) is characterized by significant limitations in both intellectual functioning and adaptive behaviors, originating before the age of 18 years. However, the genetic etiologies of ID are still incompletely elucidated due to the wide range of clinical and genetic heterogeneity. Whole genome sequencing (WGS) has been applied as a single-step clinical diagnostic tool for ID because it detects genetic variations with a wide range of resolution from single nucleotide variants (SNVs) to structural variants (SVs). To explore the causative genes for ID, we employed WGS in 45 patients from 44 unrelated Japanese families and performed a stepwise screening approach focusing on the coding variants in the genes. Here, we report 12 pathogenic and likely pathogenic variants: seven heterozygous variants of ADNP, SATB2, ANKRD11, PTEN, TCF4, SPAST, and KCNA2, three hemizygous variants of SMS, SLC6A8, and IQSEC2, and one homozygous variant in AGTPBP1. Of these, four were considered novel. Furthermore, a novel 76 kb deletion containing exons 1 and 2 in DYRK1A was identified. We confirmed the clinical and genetic heterogeneity and high frequency of de novo causative variants (8/12, 66.7%). This is the first report of WGS analysis in Japanese patients with ID. Our results would provide insight into the correlation between novel variants and expanded phenotypes of the disease.
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http://dx.doi.org/10.1002/ajmg.a.62138DOI Listing
May 2021

Clinical variations of epileptic syndrome associated with PACS2 variant.

Brain Dev 2021 Feb 23;43(2):343-347. Epub 2020 Nov 23.

Department of Pediatrics, Showa University School of Medicine, Japan.

Background: Recent studies have suggested that two PACS2 pathogenic variants, c.625G > A (p.Glu209Lys) and c.631G > A (p.Glu211Lys), have been causally linked to the characteristic developmental and epileptic encephalopathy, including autistic behaviors, hypotonia, cerebellar dysgenesis and facial dysmorphism. Their seizures appear most difficult to control in neonatal and infant period, but improve after the first year of life. We herein report three patients with the same PACS2 variant, c.625G > A (p.Glu209Lys), showing different characteristics from previous reports.

Case Report: Case 1, a 2-year-old girl, developed frequent tonic convulsions 2 weeks after birth. Brain magnetic resonance imaging showed a decrease in posterior periventricular white matter volume, an enlargement of the inferior horn of lateral ventricles and old subependymal hemorrhage. Epilepsy is now controlled with antiepileptic drugs. Case 2, a 12-year-old girl, developed generalized tonic convulsions 3 days after birth. Although epilepsy had been controlled since the age of 4, she developed Lennox-Gastaut syndrome at 9 years old. Case 3, a 3-year-old girl, developed tonic convulsions 3 days after birth. She now exhibits normal psychomotor development, and epilepsy is controlled without medicine.

Conclusion: PACS2-related epileptic syndrome presents variable phenotypes than previously reported. We think that our findings expand the clinical spectrum of this disease, and provide important information about the differential diagnosis of neonatal-onset epileptic syndrome.
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http://dx.doi.org/10.1016/j.braindev.2020.10.006DOI Listing
February 2021

A fact-finding survey of the recommendation on sedation during physiological examinations such as electroencephalogram in Japan.

Brain Dev 2021 02 14;43(2):208-213. Epub 2020 Oct 14.

Medical Safety Committee, The Japanese Society of Child Neurology, Japan; Department of Pediatrics, Saitama Medical University, Japan.

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http://dx.doi.org/10.1016/j.braindev.2020.09.012DOI Listing
February 2021

Long-Term Evaluation of Low-Dose Betamethasone for Ataxia Telangiectasia.

Pediatr Neurol 2019 11 13;100:60-66. Epub 2019 May 13.

Department of Pediatrics and Developmental Biology, Tokyo Medical and Dental University (TMDU), Tokyo, Japan. Electronic address:

Background: Ataxia telangiectasia is an autosomal recessive disorder characterized by cerebellar ataxia, telangiectases, immune defects, and a predisposition to malignancy. Quality of life is severely impaired by neurological symptoms. However, curative options for the neurological symptoms are limited. Recent studies have demonstrated short-term improvement in neurological symptoms with betamethasone therapy. However, the long-term and adverse effects of betamethasone are unclear. The aim of this study was to evaluate the long-term effects, benefits, and adverse effects of low-dose betamethasone in ataxia telangiectasia.

Methods: Six patients with ataxia telangiectasia received betamethasone at 0.02 mg/kg/day for two years. After cessation of betamethasone, the patients were observed for two additional years. Neurological assessments were performed, and adverse effects were monitored every three months throughout the four-year study period.

Results: Transient improvement of neurological symptom was observed in five of the six patients. However, after two years betamethasone treatment, only one of the six patients showed a slight improvement in the neurological score, one patient showed no change, and the neurological scores of the remaining four patients deteriorated. After the cessation of betamethasone treatment, neurological symptoms worsened in all patients. As an adverse effect of betamethasone, transient adrenal dysfunction was observed in all cases.

Conclusions: Although these findings are in agreement with previous studies suggesting that short-term betamethasone treatment transiently benefits patients with ataxia telangiectasia, the long-term benefits and risks should be carefully considered.
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http://dx.doi.org/10.1016/j.pediatrneurol.2019.05.006DOI Listing
November 2019

Comprehensive analysis of coding variants highlights genetic complexity in developmental and epileptic encephalopathy.

Nat Commun 2019 06 7;10(1):2506. Epub 2019 Jun 7.

Department of Human Genetics, Yokohama City University Graduate School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama, 236-0004, Japan.

Although there are many known Mendelian genes linked to epileptic or developmental and epileptic encephalopathy (EE/DEE), its genetic architecture is not fully explained. Here, we address this incompleteness by analyzing exomes of 743 EE/DEE cases and 2366 controls. We observe that damaging ultra-rare variants (dURVs) unique to an individual are significantly overrepresented in EE/DEE, both in known EE/DEE genes and the other non-EE/DEE genes. Importantly, enrichment of dURVs in non-EE/DEE genes is significant, even in the subset of cases with diagnostic dURVs (P = 0.000215), suggesting oligogenic contribution of non-EE/DEE gene dURVs. Gene-based analysis identifies exome-wide significant (P = 2.04 × 10) enrichment of damaging de novo mutations in NF1, a gene primarily linked to neurofibromatosis, in infantile spasm. Together with accumulating evidence for roles of oligogenic or modifier variants in severe neurodevelopmental disorders, our results highlight genetic complexity in EE/DEE, and indicate that EE/DEE is not an aggregate of simple Mendelian disorders.
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http://dx.doi.org/10.1038/s41467-019-10482-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6555845PMC
June 2019

Steroid therapy ameliorated cataplexy in three children with recent-onset of narcolepsy.

Sleep Med 2017 01 29;29:86-87. Epub 2016 Sep 29.

Department of Pediatrics, Tokyo-Kita Medical Center, Tokyo, Japan.

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http://dx.doi.org/10.1016/j.sleep.2016.01.024DOI Listing
January 2017

Light-exposed shoots of seven coexisting deciduous species show common photosynthetic responses to tree height.

Oecologia 2016 10 4;182(2):373-83. Epub 2016 Jun 4.

Faculty of Environmental Earth Science, Hokkaido University, Sapporo, 060-0810, Japan.

Functional traits of light-exposed leaves have been reported to show tree height-dependent change. However, it remains unknown how plastic response of leaf traits to tree height is linked with shoot-level carbon gain. To answer this question, we examined the photosynthetic properties of fully lit current-year shoots in crown tops with various heights for seven deciduous broad-leaved species dominated in a cool-temperate forest in northern Japan. We measured leaf mass, stomatal conductance, nitrogen content, light-saturated net photosynthetic rate (all per leaf lamina area), foliar stable carbon isotope ratio, and shoot mass allocation to leaf laminae. We employed hierarchical Bayesian models to simultaneously quantify inter-trait relationships for all species. We found that leaf and shoot traits were co-varied in association with height, and that there was no quantitative inter-specific difference in leaf- and shoot-level plastic responses to height. Nitrogen content increased and stomatal conductance decreased with height. Reflecting these antagonistic responses to height, photosynthetic rate was almost unchanged with height. Photosynthetic rate divided by stomatal conductance as a proxy of photosynthetic water use efficiency sufficiently explained the variation of foliar carbon isotope ratio. The increase in mass allocation to leaves in a shoot compensated for the height-dependent decline in photosynthetic rate per leaf lamina mass. Consequently, photosynthetic gain at the scale of current-year shoot mass was kept unchanged with tree height. We suggest that the convergent responses of shoot functional traits across species reflect common requirements for trees coexisting in a forest.
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http://dx.doi.org/10.1007/s00442-016-3664-8DOI Listing
October 2016

Circadian Rhythms of Oxidative Stress Markers and Melatonin Metabolite in Patients with Xeroderma Pigmentosum Group A.

Oxid Med Cell Longev 2016 26;2016:5741517. Epub 2016 Apr 26.

Department of Brain Development and Neural Regeneration, Tokyo Metropolitan Institute of Medical Science, Tokyo 156-8506, Japan.

Xeroderma pigmentosum group A (XPA) is a genetic disorder in DNA nucleotide excision repair (NER) with severe neurological disorders, in which oxidative stress and disturbed melatonin metabolism may be involved. Herein we confirmed the diurnal variation of melatonin metabolites, oxidative stress markers, and antioxidant power in urine of patients with XPA and age-matched controls, using enzyme-linked immunosorbent assay (ELISA). The peak of 6-sulfatoxymelatonin, a metabolite of melatonin, was seen at 6:00 in both the XPA patients and controls, though the peak value is lower, specifically in the younger age group of XPA patients. The older XPA patients demonstrated an increase in the urinary levels of 8-hydroxy-2'-deoxyguanosine and hexanoyl-lysine, a marker of oxidative DNA damage and lipid peroxidation, having a robust peak at 6:00 and 18:00, respectively. In addition, the urinary level of total antioxidant power was decreased in the older XPA patients. Recently, it is speculated that oxidative stress and antioxidant properties may have a diurnal variation, and the circadian rhythm is likely to influence the NER itself. We believe that the administration of melatonin has the possibility of ameliorating the augmented oxidative stress in neurodegeneration, especially in the older XPA patients, modulating the melatonin metabolism and the circadian rhythm.
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http://dx.doi.org/10.1155/2016/5741517DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4861809PMC
March 2017

The Role of ARX in Human Pancreatic Endocrine Specification.

PLoS One 2015 3;10(12):e0144100. Epub 2015 Dec 3.

Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, British Columbia, Canada.

The in vitro differentiation of human embryonic stem cells (hESCs) offers a model system to explore human development. Humans with mutations in the transcription factor Aristaless Related Homeobox (ARX) often suffer from the syndrome X-linked lissencephaly with ambiguous genitalia (XLAG), affecting many cell types including those of the pancreas. Indeed, XLAG pancreatic islets lack glucagon and pancreatic polypeptide-positive cells but retain somatostatin, insulin, and ghrelin-positive cells. To further examine the role of ARX in human pancreatic endocrine development, we utilized genomic editing in hESCs to generate deletions in ARX. ARX knockout hESCs retained pancreatic differentiation capacity and ARX knockout endocrine cells were biased toward somatostatin-positive cells (94% of endocrine cells) with reduced pancreatic polypeptide (rarely detected), glucagon (90% reduced) and insulin-positive (65% reduced) lineages. ARX knockout somatostatin-positive cells shared expression patterns with human fetal and adult δ-cells. Differentiated ARX knockout cells upregulated PAX4, NKX2.2, ISL1, HHEX, PCSK1, PCSK2 expression while downregulating PAX6 and IRX2. Re-expression of ARX in ARX knockout pancreatic progenitors reduced HHEX and increased PAX6 and insulin expression following differentiation. Taken together these data suggest that ARX plays a key role in pancreatic endocrine fate specification of pancreatic polypeptide, somatostatin, glucagon and insulin positive cells from hESCs.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0144100PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4669132PMC
June 2016

Efficacy of generic allometric equations for estimating biomass: a test in Japanese natural forests.

Ecol Appl 2015 Jul;25(5):1433-46

Accurate estimation of tree and forest biomass is key to evaluating forest ecosystem functions and the global carbon cycle. Allometric equations that estimate tree biomass from a set of predictors, such as stem diameter and tree height, are commonly used. Most allometric equations are site specific, usually developed from a small number of trees harvested in a small area, and are either species specific or ignore interspecific differences in allometry. Due to lack of site-specific allometries, local equations are often applied to sites for which they were not originally developed (foreign sites), sometimes leading to large errors in biomass estimates. In this study, we developed generic allometric equations for aboveground biomass and component (stem, branch, leaf, and root) biomass using large, compiled data sets of 1203 harvested trees belonging to 102 species (60 deciduous angiosperm, 32 evergreen angiosperm, and 10 evergreen gymnosperm species) from 70 boreal, temperate, and subtropical natural forests in Japan. The best generic equations provided better biomass estimates than did local equations that were applied to foreign sites. The best generic equations included explanatory variables that represent interspecific differences in allometry in addition to stem diameter, reducing error by 4-12% compared to the generic equations that did not include the interspecific difference. Different explanatory variables were selected for different components. For aboveground and stem biomass, the best generic equations had species-specific wood specific gravity as an explanatory variable. For branch, leaf, and root biomass, the best equations had functional types (deciduous angiosperm, evergreen angiosperm, and evergreen gymnosperm) instead of functional traits (wood specific gravity or leaf mass per area), suggesting importance of other traits in addition to these traits, such as canopy and root architecture. Inclusion of tree height in addition to stem diameter improved the performance of the generic equation only for stem biomass and had no apparent effect on aboveground, branch, leaf, and root biomass at the site level. The development of a generic allometric equation taking account of interspecific differences is an effective approach for accurately estimating aboveground and component biomass in boreal, temperate, and subtropical natural forests.
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http://dx.doi.org/10.1890/14-0175.1DOI Listing
July 2015

SPTAN1 encephalopathy: distinct phenotypes and genotypes.

J Hum Genet 2015 Apr 29;60(4):167-73. Epub 2015 Jan 29.

Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, Japan.

Recent progress in genetic analysis reveals that a significant proportion of cryptogenic epileptic encephalopathies are single-gene disorders. Mutations in numerous genes for early-onset epileptic encephalopathies have been rapidly identified, including in SPTAN1, which encodes α-II spectrin. The aim of this review is to delineate SPTAN1 encephalopathy as a distinct clinical syndrome. To date, a total of seven epileptic patients with four different in-frame SPTAN1 mutations have been identified. The major clinical features of SPTAN1 mutations include epileptic encephalopathy with hypsarrhythmia, no visual attention, acquired microcephaly, spastic quadriplegia and severe intellectual disability. Brainstem and cerebellar atrophy and cerebral hypomyelination, as observed by magnetic resonance imaging, are specific hallmarks of this condition. A milder variant is characterized by generalized epilepsy with pontocerebellar atrophy. Only in-frame SPTAN1 mutations in the last two spectrin repeats in the C-terminal region lead to dominant negative effects and these specific phenotypes. The last two spectrin repeats are required for α/β spectrin heterodimer associations and the mutations can alter heterodimer formation between the two spectrins. From these data we suggest that SPTAN1 encephalopathy is a distinct clinical syndrome owing to specific SPTAN1 mutations. It is important that this syndrome is recognized by pediatric neurologists to enable proper diagnostic work-up for patients.
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http://dx.doi.org/10.1038/jhg.2015.5DOI Listing
April 2015

Changes in cerebrospinal fluid biomarkers in human herpesvirus-6-associated acute encephalopathy/febrile seizures.

Mediators Inflamm 2014 11;2014:564091. Epub 2014 Sep 11.

Department of Brain Development and Neural Regeneration, Tokyo Metropolitan Institute of Medical Science, Tokyo 156-8506, Japan.

To determine the involvement of oxidative stress in the pathogenesis of acute encephalopathy associated with human herpesvirus-6 (HHV-6) infection, we measured the levels of oxidative stress markers 8-hydroxy-2'-deoxyguanosine (8-OHdG) and hexanoyl-lysine adduct (HEL), tau protein, and cytokines in cerebrospinal fluid (CSF) obtained from patients with HHV-6-associated acute encephalopathy (HHV-6 encephalopathy) (n = 16) and complex febrile seizures associated with HHV-6 (HHV-6 complex FS) (n = 10). We also examined changes in CSF-8OHdG and CSF-HEL levels in patients with HHV-6 encephalopathy before and after treatment with edaravone, a free radical scavenger. CSF-8-OHdG levels in HHV-6 encephalopathy and HHV-6 complex FS were significantly higher than in control subjects. In contrast, CSF-HEL levels showed no significant difference between groups. The levels of total tau protein in HHV-6 encephalopathy were significantly higher than in control subjects. In six patients with HHV-6 infection (5 encephalopathy and 1 febrile seizure), the CSF-8-OHdG levels of five patients decreased after edaravone treatment. Our results suggest that oxidative DNA damage is involved in acute encephalopathy associated with HHV-6 infection.
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http://dx.doi.org/10.1155/2014/564091DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4177780PMC
June 2015

Pathological changes in cardiac muscle and cerebellar cortex in Vici syndrome.

Am J Med Genet A 2014 Dec 24;164A(12):3203-5. Epub 2014 Sep 24.

Department of Pediatrics, Tokyo Medical and Dental University, Tokyo, Japan.

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http://dx.doi.org/10.1002/ajmg.a.36753DOI Listing
December 2014

Cerebrospinal fluid oxidative stress marker levels and cytokine concentrations in a neonate with incontinentia pigmenti.

Pediatr Neurol 2014 Nov 30;51(5):737-40. Epub 2014 Jul 30.

Department of Pediatrics, Faculty of Medicine, Juntendo University, Tokyo, Japan.

Background: Some children with incontinentia pigmenti exhibit encephalopathic features with severe seizures and disturbed consciousness, from the neonatal through the early infantile period. However, the pathological mechanism of brain lesion development is not fully understood.

Methods: We measured the cerebrospinal fluid levels of cytokines and oxidative stress markers (8-hydroxy-2-deoxyguanosine and the hexanoyl-lysine adduct) in a young girl with incontinentia pigmenti complicated by an encephalopathic event that occurred on her first day of life. Magnetic resonance imaging revealed widespread reduction of water diffusion in the basal ganglia, the periventricular and subcortical white matter, and the corpus callosum.

Results: Oxidative stress markers were elevated at 4 days of age but decreased mildly by 25 days of age. Elevated levels of soluble tumor necrosis factor receptor 1 were observed at both 4 and 25 days of age, although tumor necrosis factor-α levels were below the limit of detection. No other cytokine levels were elevated, except for those of interleukin-10 at 25 days of age.

Conclusions: Tumor necrosis factor-α expression and oxidative stress are involved in the pathogenesis of brain lesions in children with incontinentia pigmenti, and elevated cerebrospinal fluid cytokine levels may not be apparent during encephalopathic events.
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http://dx.doi.org/10.1016/j.pediatrneurol.2014.07.023DOI Listing
November 2014

Hounsfield unit values of retropharyngeal abscess-like lesions seen in Kawasaki disease.

Acta Otolaryngol 2014 Apr 10;134(4):437-40. Epub 2014 Feb 10.

Departments of 1Otolaryngology.

Conclusions: Retropharyngeal abscess-like lesions are occasionally seen in computed tomography (CT) imaging of patients with Kawasaki disease (KD) and these patients often undergo unnecessary surgery. We could distinguish the lesions from true abscesses by measuring their Hounsfield unit values (HUs).

Objective: To distinguish the retropharyngeal abscess-like lesions from true abscesses without any surgical procedure.

Methods: We investigated six cases of KD showing such lesions on CTs, both with and without contrast enhancement (CE). We measured the HUs of those lesions and compared them with those of 10 true abscesses as controls.

Results: Abscess-like lesions of KD were well enhanced by CE, whereas abscesses showed virtually no enhancement. The mean HU in the six KD cases was 20.0 ± 4.65 (mean ± SD) on plain CTs and 35.6 ± 4.49 on contrast CTs. In abscesses, it was 30.3 ± 4.42 on plain CTs and 30.3 ± 3.57 on contrast CTs. The difference in HU values [(HU on contrast CT) - (HU on plain CT)] was defined as ΔHU. The mean ΔHU was 15.6 ± 5.36 in the six KD lesions and 0.0 ± 2.93 in abscesses, with statistical significance of p < 0.0001 by Student's t test. Thus, ΔHU value may potentially be a useful parameter for their distinction.
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http://dx.doi.org/10.3109/00016489.2013.878475DOI Listing
April 2014

Melatonin alterations and brain acetylcholine lesions in sleep disorders in Cockayne syndrome.

Brain Dev 2014 Nov 3;36(10):907-13. Epub 2014 Feb 3.

Department of Brain Development and Neural Regeneration, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan. Electronic address:

Background: Cockayne syndrome (CS) is a genetic disorder caused by deficient nucleotide excision repair. Patients with CS exhibit progeroid features, developmental delay, and various neurological disorders; they are also known to suffer from sleep problems, which have never been investigated in detail.

Objective: The aim of this study is to investigate the pathogenesis of sleep disorders in patients with CS.

Methods: We performed a questionnaire survey of the families of patients with CS, enzyme-linked immunosorbent analyses of the melatonin metabolite, 6-sulphatoxymelatonin (6-SM), in the patients' urine, and immunohistochemistry in the hypothalamus, the basal nucleus of Meynert (NbM), and the pedunculopontine tegmental nucleus (PPN) in four autopsy cases.

Results: Sleep-wakefulness rhythms were disturbed in patients with CS, and these disturbances seemed to be related to a reduced urinary excretion of 6-SM. In addition, although the hypothalamic nuclei were comparatively preserved, acetylcholine neurons (AchNs) were severely decreased in the NbM and PPN.

Conclusions: AchNs modulate both arousal and rapid eye movement sleep, and selective lesions of AchNs in the PPN and/or NbM in combination with disturbed melatonin metabolism might be involved in the sleep disorders in CS.
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http://dx.doi.org/10.1016/j.braindev.2014.01.004DOI Listing
November 2014

Recessive mutations in EPG5 cause Vici syndrome, a multisystem disorder with defective autophagy.

Nat Genet 2013 Jan 9;45(1):83-7. Epub 2012 Dec 9.

DNA Laboratory, Guy's and St Thomas' Serco Pathology, Guy's Hospital, London, UK.

Vici syndrome is a recessively inherited multisystem disorder characterized by callosal agenesis, cataracts, cardiomyopathy, combined immunodeficiency and hypopigmentation. To investigate the molecular basis of Vici syndrome, we carried out exome and Sanger sequence analysis in a cohort of 18 affected individuals. We identified recessive mutations in EPG5 (previously KIAA1632), indicating a causative role in Vici syndrome. EPG5 is the human homolog of the metazoan-specific autophagy gene epg-5, encoding a key autophagy regulator (ectopic P-granules autophagy protein 5) implicated in the formation of autolysosomes. Further studies showed a severe block in autophagosomal clearance in muscle and fibroblasts from individuals with mutant EPG5, resulting in the accumulation of autophagic cargo in autophagosomes. These findings position Vici syndrome as a paradigm of human multisystem disorders associated with defective autophagy and suggest a fundamental role of the autophagy pathway in the immune system and the anatomical and functional formation of organs such as the brain and heart.
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http://dx.doi.org/10.1038/ng.2497DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4012842PMC
January 2013

Autoimmune neurological disorders associated with group-A beta-hemolytic streptococcal infection.

Brain Dev 2013 Aug 9;35(7):670-4. Epub 2012 Nov 9.

Department of Neuropediatrics, Tokyo Metropolitan Neurological Hospital, Tokyo, Japan.

Although central nervous system (CNS) disorders associated with group-A beta-hemolytic streptococcal (GABHS) infection occur only rarely, Sydenham's chorea is a well-recognized disease that can arise following infection. Children may develop a tic, obsessive compulsive disorder (OCD), and extrapyramidal movement subsequent to GABHS infection. These disorders have been termed pediatric autoimmune neuropsychiatric disorders associated with streptococci (PANDAS). Herein we report one case each of acute disseminated encephalomyelitis (ADEM), PANDAS and subacute encephalitis associated with GABHS infection. To evaluate the pathogenesis of the CNS disorders associated with GABHS infection, we measured levels of neurotransmitters, cytokines, anti-neuronal autoantibodies, and performed immunohistochemistry using patient sera to stain human brain sections. All three cases showed psychiatric behavioral disorders. Immunotherapy was effective, and homovanillic acid levels in the cerebrospinal fluid (CSF) were elevated at the acute stage in all three cases. In each case of ADEM and PANDAS, immunohistochemistry demonstrated neuronal impairment in the basal ganglia during the acute stage. Neuronal immunoreactivity was visualized in the cerebral cortex at the acute stage in the case of subacute encephalitis. There was no direct correlation between immunoreactivity of patient sera on the brain sections and positivity of anti-neuronal autoantibodies or CSF biomarkers. The results suggest that autoimmune responses may modulate neurotransmission, and the use of patient serum for immunohistochemistry is a sensitive screening method for the detection of anti-neuronal autoantibodies in CNS disorders associated with GABHS infection.
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http://dx.doi.org/10.1016/j.braindev.2012.10.003DOI Listing
August 2013

Genetic analysis of PRRT2 for benign infantile epilepsy, infantile convulsions with choreoathetosis syndrome, and benign convulsions with mild gastroenteritis.

Brain Dev 2013 Jun 13;35(6):524-30. Epub 2012 Oct 13.

Department of Pediatrics, School of Medicine, Fukuoka University, Fukuoka, Japan.

Purpose: PRRT2 mutations were recently identified in benign familial infantile epilepsy (BFIE) and infantile convulsions with paroxysmal choreoathetosis (ICCA) but no abnormalities have so far been identified in their phenotypically similar seizure disorder of benign convulsions with mild gastroenteritis (CwG), while mutations in KCNQ2 and KCNQ3 have been recognized in benign familial neonatal epilepsy (BFNE). The aim of this study was to identify PRRT2 mutations in infantile convulsions in Asian families with BFIE and ICCA, CwG and BFNE.

Methods: We recruited 26 unrelated Japanese affected with either BFIE or non-familial benign infantile seizures and their families, including three families with ICCA. A total of 17 Japanese and Taiwanese with CwG, 50 Japanese with BFNE and 96 healthy volunteers were also recruited. Mutations of PRRT2 were sought using direct sequencing.

Results: Heterozygous truncation mutation (c.649dupC) was identified in 15 of 26 individuals with benign infantile epilepsy (52.1%). All three families of ICCA harbored the same mutation (100%). Another novel mutation (c.1012+2dupT) was found in the proband of a family with BFIE. However, no PRRT2 mutation was found in either CwG or BFNE.

Conclusions: The results confirm that c.649dupC, a truncating mutation of PRRT2, is a hotspot mutation resulting in BFIE or ICCA regardless of the ethnic background. In contrast, PRRT2 mutations do not seem to be associated with CwG or BFNE. Screening for PRRT2 mutation might be useful in early-stage differentiation of BFIE from CwG.
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http://dx.doi.org/10.1016/j.braindev.2012.09.006DOI Listing
June 2013

Lesions of acetylcholine neurons in refractory epilepsy.

ISRN Neurol 2012 9;2012:404263. Epub 2012 Aug 9.

Department of Brain Development and Neural Regeneration, Tokyo Metropolitan Institute of Medical Science, Tokyo 156-8506, Japan.

We have examined brainstem lesions in patients with refractory epilepsy disorders, including West syndrome (WS), Lennox-Gastaut syndrome (LGS), and dentatorubral-pallidoluysian atrophy (DRPLA). Acetylcholinergic neurons (AchNs) in the pedunculopontine tegmental nucleus (PPN) are involved in mental development, and disruption of neuronal nicotinic acetylcholine receptors can lead to epilepsy. In order to investigate the involvement of lesions of AchNs in refractory epilepsy, we performed immunohistochemical analyses of AchNs in the PPN in autopsy cases who had a past history of WS and/or LGS and in DRPLA cases who showed progressive myoclonic epilepsy. In addition, we performed a preliminary quantification of the levels of acetylcholine, neuropeptides, and monoamine metabolites in the cerebrospinal fluid (CSF) of patients with WS and benign convulsions associated with mild gastroenteritis (CwG). In the PPN analysis, the total number of neurons and the number of AchNs were reduced in WS/LGS and WS cases, while DRPLA cases showed a decrease in the number and percentage of AchNs. In the CSF analysis, WS patients demonstrated a reduction in the levels of inhibitory neuropeptides, while CwG patients showed increased levels of acetylcholine and decreased levels of serotonin metabolites. These data suggest the possible involvement of lesions of AchNs in WS and DRPLA.
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http://dx.doi.org/10.5402/2012/404263DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3425792PMC
August 2012

Oxidative stress in developmental brain disorders.

Adv Exp Med Biol 2012 ;724:278-90

Department of Clinical Neuropathology, Tokyo Metropolitan Institute for Neuroscience, Tokyo, Japan.

In order to examine the involvement of oxidative stress in developmental brain disorders, we have performed immunohistochemistry in autopsy brains and enzyme-linked immunosorbent assay (ELISA) in the cerebrospinal fluid and urines of patients. Here, we review our data on the hereditary DNA repair disorders, congenital metabolic errors and childhood-onset neurodegenerative disorders. First, in our studies on hereditary DNA repair disorders, increased oxidative DNA damage and lipid peroxidation were carried out in the degeneration of basal ganglia, intracerebral calcification and cerebellar degeneration in patients with xeroderma pigmentosum, Cockayne syndrome and ataxia-telangiectasia-like disorder, respectively. Next, congenital metabolic errors, apoptosis due to lipid peroxidation seemed to cause neuronal damage in neuronal ceroid-lipofuscinosis. Oxidative stress of DNA combined with reduced expression of antioxidant enzymes occurred in the lesion of the cerebral cortex in mucopolysaccharidoses and mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes. In childhood-onset neurodegenerative disorders, increased oxidative DNA damage and lipid peroxidation may lead to motor neuron death in spinal muscular atrophy like in amyotrophic lateral sclerosis. In patients with dentatorubral-pallidoluysian atrophy, a triplet repeat disease, deposition of oxidative products of nucleosides and reduced expression of antioxidant enzymes were found in the lenticular nucleus. In contrast, the involvement of oxidative stress is not definite in patients with Lafora disease. Rett syndrome patients showed changes of oxidative stress markers and antioxidant power in urines, although the changes may be related to systemic complications.
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http://dx.doi.org/10.1007/978-1-4614-0653-2_21DOI Listing
April 2012

Common allometric response of open-grown leader shoots to tree height in co-occurring deciduous broadleaved trees.

Ann Bot 2011 Nov 13;108(7):1279-86. Epub 2011 Sep 13.

Graduate School of Environmental Science, Hokkaido University, Kita-ku, Sapporo, 060-0810, Japan.

Background And Aims: Morphology of crown shoots changes with tree height. The height of forest trees is usually correlated with the light environment and this makes it difficult to separate the effects of tree size and of light conditions on the morphological plasticity of crown shoots. This paper addresses the tree-height dependence of shoot traits under full-light conditions where a tree crown is not shaded by other crowns.

Methods: Focus is given to relationships between tree height and top-shoot traits, which include the shoot's leaf-blades and non-leafy mass, its total leaf-blade area and the length and basal diameter of the shoot's stem. We examine the allometric characteristics of open-grown current-year leader shoots at the tops of forest tree crowns up to 24 m high and quantify their responses to tree height in 13 co-occurring deciduous hardwood species in a cool-temperate forest in northern Japan.

Key Results: Dry mass allocated to leaf blades in a leader shoot increased with tree height in all 13 species. Specific leaf area decreased with tree height. Stem basal area was almost proportional to total leaf area in a leader shoot, where the proportionality constant did not depend on tree height, irrespective of species. Stem length for a given stem diameter decreased with tree height.

Conclusions: In the 13 species observed, height-dependent changes in allometry of leader shoots were convergent. This finding suggests that there is a common functional constraint in tree-height development. Under full-light conditions, leader shoots of tall trees naturally experience more severe water stress than those of short trees. We hypothesize that the height dependence of shoot allometry detected reflects an integrated response to height-associated water stress, which contributes to successful crown expansion and height gain.
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http://dx.doi.org/10.1093/aob/mcr228DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3197456PMC
November 2011

Oxidative stress markers and phosphorus magnetic resonance spectroscopy in a patient with GLUT1 deficiency treated with modified Atkins diet.

Brain Dev 2012 May 30;34(5):372-5. Epub 2011 Aug 30.

Department of Pediatrics, Juntendo University School of Medicine, Japan.

Glucose transporter type 1 deficiency syndrome is an inborn error of glucose transport across blood-tissue barriers, and the modified Atkins diet is an effective and well-tolerated treatment. To investigate the effects of the modified Atkins diet, we examined the cerebrospinal fluid markers and performed phosphorus magnetic resonance spectroscopy in a patient with glucose transporter type 1 deficiency syndrome before and after the modified Atkins diet. Cerebrospinal fluid levels of the oxidative stress markers, 8-hydroxy-2'-deoxyguanosine and hexanoyl-lysine adduct, were markedly increased above the cutoff index and were normalized 18 months after the modified Atkins diet. Phosphorus magnetic resonance spectroscopy measurements showed 18% increase of PCr/γ-ATP ratio after the modified Atkins diet. These results suggest that the modified Atkins diet may reduce oxidative stress in the brain and improve energy reserve capacity, which is important in sustaining electrophysiological activities essential for performing brain functions.
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http://dx.doi.org/10.1016/j.braindev.2011.08.005DOI Listing
May 2012

Focal encephalopathy with recurrent episodes of epileptic status and cluster mimicking hemiconvulsion-hemiplegia-epilepsy syndrome.

Brain Dev 2012 May 12;34(5):360-3. Epub 2011 Jul 12.

Department of Pediatrics, Tokyo-Kita Social Insurance Hospital, Tokyo, Japan.

Hemiconvulsion-hemiplegia-epilepsy syndrome is characterized by unilateral convulsions during fever, transient hemiplegia, and subsequent partial epilepsy with atrophy in the cerebrum. A 9-year-old boy with a history of West syndrome and hypoglycemic attacks had three episodes of epileptic status and clusters mimicking HHE syndrome over a 2-year period. Magnetic resonance imaging revealed the involvement of the right and left cerebrums. Because no abnormalities were detected in an endocrine examination, screening tests for metabolic errors, or magnetic resonance spectroscopy, a diagnosis of metabolic errors was not supported. Immunohistochemistry using the patient's sera showed binding of the serum immunoglobulin with neurons in the temporal and occipital cerebral cortices, indicating the possible involvement of autoimmune mechanisms in this case. Focal encephalopathy should be considered in children showing convulsions, psychiatric disorders, and/or involuntary movements for several months in a row. In such cases, immunohistochemistry using the patient's sera may be useful for the investigation of the pathogenesis of the illness.
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http://dx.doi.org/10.1016/j.braindev.2011.06.011DOI Listing
May 2012

Oxidative stress in patients with clinically mild encephalitis/encephalopathy with a reversible splenial lesion (MERS).

Brain Dev 2012 Feb 14;34(2):124-7. Epub 2011 May 14.

Department of Pediatrics, Tokyo-Kita Social Insurance Hospital, Kita-ku, Tokyo, Japan.

We examined oxidative stress markers, tau protein and cytokines in the cerebrospinal fluid (CSF) in six patients with clinically mild encephalitis/encephalopathy with a reversible splenial lesion (MERS). In the CSF, 8-hydroxy-2'-deoxyguanosine (8-OHdG) and hexanoyl-lysine adduct levels increased over the cutoff index in four and one out of six MERS patients, respectively. The CSF IL-6 and IL-10 levels were increased in three out of six patients, two of which had extended lesion of the cerebral white matter. The CSF value of tau protein, marker of the axonal damage, was not increased, and neuron specific enolase (NSE) in the CSF was not increased. The increased 8-OHdG levels in the CSF, DNA oxidative stress marker, in four MERS patients, suggesting involvement of oxidative stress in MERS. MERS is occasionally accompanied with hyponatremia, although our patients lacked hyponatremia. It is possible that the disequilibrium of systemic metabolism including electrolytes may lead to facilitation of oxidative stress and reversible white matter lesion in MERS. The increase of cytokine production seems to be involved in the distribution of lesions in MERS.
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http://dx.doi.org/10.1016/j.braindev.2011.04.004DOI Listing
February 2012

Liver-specific mitochondrial respiratory chain complex I deficiency in fatal influenza encephalopathy.

Brain Dev 2012 Feb 26;34(2):115-7. Epub 2011 Mar 26.

Department of Pediatrics and Child Health, Nihon University School of Medicine, Tokyo, Japan.

We report on a 4-year-old boy who died from influenza encephalopathy. The clinical course and microscopic findings of the autopsied liver were compatible with Reye's syndrome. We examined the mitochondrial respiratory chain function by blue native polyacrylamide gel electrophoresis (BN-PAGE), western blotting, and respiratory chain enzyme activity assays. The activity of liver respiratory chain complex (CO) I was markedly decreased (7.2% of the respective control activity); whereas, the other respiratory chain complex activities were substantially normal (CO II, 57.9%; CO III, 122.3%; CO IV, 161.0%). The activities of CO I-IV in fibroblasts were normal (CO I, 82.0%; CO II, 83.1%; CO III, 72.9%; CO IV, 97.3%). The patient was diagnosed with liver-specific complex I deficiency. This inborn disorder may have contributed to the fatal outcome. We propose that relying only on fibroblast respiratory chain complex activities may lead to the misdiagnosis of liver-specific complex I deficiency.
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http://dx.doi.org/10.1016/j.braindev.2011.03.002DOI Listing
February 2012

Decrease in acetylcholinergic neurons in the pedunculopontine tegmental nucleus in a patient with Prader-Willi syndrome.

Neuropathology 2011 Jun 29;31(3):280-5. Epub 2010 Sep 29.

Department of Clinical Neuropathology, Tokyo Metropolitan Institute for Neuroscience, Fuchu-shi, Tokyo, Japan.

Prader-Willi syndrome (PWS) is caused by the absence of paternally contributed genes in chromosome 15, and is characterized by hypotonia, feeding difficulty, mental retardation, growth failure, hypogonadism and severe obesity. To elucidate the pathogenesis of neurological disorders, we immunohistochemically examined the γ-aminobutyric acid (GABA)ergic interneurons (GABAis) in the cerebral cortex and acetylcholine neurons (AchNs) in the nucleus basalis of Meynert (MyN) and pedunculopontine tegmental nucleus pars compacta (PPNc) in an autopsy case of one PWS patient with a deletion in the 15q11-q12 region and three control patients. The GABAis in the cerebral cortex and AchNs in the MyN were well preserved in the PWS patient. The AchNs in the PPNc in the PWS patient were severely reduced in comparison with those in controls, whereas catecholaminergic neurons and GABAis were preserved. The selective loss of AchNs in the PPNc may be involved in hypotonia and/or REM sleep abnormalities in PWS patients.
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http://dx.doi.org/10.1111/j.1440-1789.2010.01157.xDOI Listing
June 2011

Neocortical layer formation of human developing brains and lissencephalies: consideration of layer-specific marker expression.

Cereb Cortex 2011 Mar 12;21(3):588-96. Epub 2010 Jul 12.

Department of Mental Retardation and Birth Defect Research, National Center of Neurology and Psychiatry, Kodaira, 187-8502, Japan.

To investigate layer-specific molecule expression in human developing neocortices, we performed immunohistochemistry of the layer-specific markers (TBR1, FOXP1, SATB2, OTX1, CUTL1, and CTIP2), using frontal neocortices of the dorsolateral precentral gyri of 16 normal controls, aged 19 gestational weeks to 1 year old, lissencephalies of 3 Miller-Dieker syndrome (MDS) cases, 2 X-linked lissencephaly with abnormal genitalia (XLAG) cases, and 4 Fukuyama-type congenital muscular dystrophy (FCMD) cases. In the fetal period, we observed SATB2+ cells in layers II-IV, CUTL1+ cells in layers II-V, FOXP1+ cells in layer V, OTX1+ cells in layers II or V, and CTIP2+ and TBR1+ cells in layers V and VI. SATB2+ and CUTL1+ cells appeared until 3 months of age, but the other markers disappeared after birth. Neocortices of MDS and XLAG infants revealed SATB2+, CUTL1+, FOXP1+, and TBR1+ cells diffusely located in the upper layers. In fetal FCMD neocortex, neurons labeled with the layer-specific markers located over the glia limitans. The present study provided new knowledge indicating that the expression pattern of these markers in the developing human neocortex was similar to those in mice. Various lissencephalies revealed abnormal layer formation by random migration.
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http://dx.doi.org/10.1093/cercor/bhq125DOI Listing
March 2011

Partial loss of pancreas endocrine and exocrine cells of human ARX-null mutation: consideration of pancreas differentiation.

Differentiation 2010 Sep-Oct;80(2-3):118-22. Epub 2010 Jun 9.

Department of Mental Retardation and Birth Defect Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry, 4-1-1 Ogawahigashi, Kodaira, Tokyo 187-8502, Japan.

Aristaless-related homeobox gene (ARX) mutation leads to several neurological disorders including X-linked lissencephaly with abnormal genitalia (XLAG), West syndrome and Partington syndrome, with XLAG being the most severe form. Although some of the brain pathologies of XLAG have already been described, the crucial extra-brain symptoms are severe growth retardation, transient hyperglycemia and intractable diarrhea. Since ARX expresses in the islets of Langerhans during the embryonic stage, these visceral phenotypes may be related to a loss of ARX function, which develops endocrine cells in the pancreas. We investigated the abnormal pancreatic development of XLAG patients with ARX-null mutation. We performed immunohistochemistry of XLAG pancreases, using the antibodies against glucagon, insulin, somatostatin, pancreatic polypeptide, ghrelin, Brn4, Nkx2.2, Mash1, amylase and pancreatic lipase. As the results, the glucagon- and pancreatic polypeptide-producing cells were found to be completely deficient in the islets of Langerhans. We also discovered marked interstitial fibrosis, small exocrine cells with loss of amylase-producing cells and an enlargement of the central lumen of the glandular acini. These pathological findings indicate that ARX contributes not only to endocrine development, but also to exocrine development of the human pancreas, and its deficiency may lead to the severe phenotypes of XLAG patients.
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http://dx.doi.org/10.1016/j.diff.2010.05.003DOI Listing
January 2011