基本情報
- 所属
- 自治医科大学 医学部小児科学講座 / 医学部小児科学講座 小児医学部門 教授
- 研究者番号
- 90426320
- J-GLOBAL ID
- 201401039803985369
- researchmap会員ID
- B000238601
- 外部リンク
経歴
10論文
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Different patterns of cerebellar abnormality and hypomyelination between POLR3A and POLR3B mutationsBRAIN & DEVELOPMENT 36(3) 259-263 2014年3月 査読有りBackground: Mutations of POLR3A and POLR3B have been reported to cause several allelic hypomyelinating disorders, including hypomyelination with hypogonadotropic hypogonadism and hypodontia (4H syndrome). Patients and methods: To clarify the difference in MRI between the two genotypes, we reviewed MRI in three patients with POLR3B mutations, and three with POLR3A mutations. Results: Though small cerebellar hemispheres and vermis are common MRI findings with both types of mutations, MRI in patients with POLR3B mutations revealed smaller cerebellar structures, especially vermis, than those in POLR3A mutations. MRI also showed milder hypomyelination in patients with POLR3B mutations than those with POLR3A mutations, which might explain milder clinical manifestations. Conclusions: MRI findings are distinct between patients with POLR3A and 3B mutations, and can provide important clues for the diagnosis, as these patients sometimes have no clinical symptoms suggesting 4H syndrome. (C) 2013 The Japanese Society of Child Neurology. Published by Elsevier B.V. All rights reserved.
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Rheumatology (Oxford, England) 53(3) 448-458 2014年3月 査読有り
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HUMAN GENETICS 133(2) 225-234 2014年2月 査読有りLeigh syndrome (LS) is an early-onset progressive neurodegenerative disorder characterized by unique, bilateral neuropathological findings in brainstem, basal ganglia, cerebellum and spinal cord. LS is genetically heterogeneous, with the majority of the causative genes affecting mitochondrial malfunction, and many cases still remain unsolved. Here, we report male sibs affected with LS showing ketonemia, but no marked elevation of lactate and pyruvate. To identify their genetic cause, we performed whole exome sequencing. Candidate variants were narrowed down based on autosomal recessive and X-linked recessive models. Only one hemizygous missense mutation (c.665G > C, p.W222S) in glycogenin-2 (GYG2) (isoform a: NM_001079855) in both affected sibs and a heterozygous change in their mother were identified, being consistent with the X-linked recessive trait. GYG2 encodes glycogenin-2 (GYG2) protein, which plays an important role in the initiation of glycogen synthesis. Based on the structural modeling, the mutation can destabilize the structure and result in protein malfunctioning. Furthermore, in vitro experiments showed mutant GYG2 was unable to undergo the self-glucosylation, which is observed in wild-type GYG2. This is the first report of GYG2 mutation in human, implying a possible link between GYG2 abnormality and LS.
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EPILEPSIA 55(2) E13-E17 2014年2月 査読有りAberrations in the glycosylphosphatidylinositol (GPI)-anchor biosynthesis pathway constitute a subclass of congenital disorders of glycosylation, and mutations in seven genes involved in this pathway have been identified. Among them, mutations in PIGV and PIGO, which are involved in the late stages of GPI-anchor synthesis, and PGAP2, which is involved in fatty-acid GPI-anchor remodeling, are all causative for hyperphosphatasia with mental retardation syndrome (HPMRS). Using whole exome sequencing, we identified novel compound heterozygous PIGO mutations (c.389C>A [p.Thr130Asn] and c.1288C>T [p.Gln430*]) in two siblings, one of them having epileptic encephalopathy. GPI-anchored proteins (CD16 and CD24) on blood granulocytes were slightly decreased compared with a control and his mother. Our patients lacked the characteristic features of HPMRS, such as facial dysmorphology (showing only a tented mouth) and hypoplasia of distal phalanges, and had only a mild elevation of serum alkaline phosphatase (ALP). Our findings therefore expand the clinical spectrum of GPI-anchor deficiencies involving PIGO mutations to include epileptic encephalopathy with mild elevation of ALP.
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Epilepsy Research 108(4) 725-731 2014年 査読有りPurpose: To evaluate the efficacy and safety of stiripentol as add-on therapy in Japanese patients with Dravet syndrome treated with clobazam (CLB) and valproate (VPA). Methods: In this open-label study, patients aged 1-30 years entered a 4-week baseline phase, followed by a 4-week stiripentol dose-adjustment and 12-week fixed-dose phase. The primary efficacy endpoint was responder rate (proportion of patients with a ≥50% reduction from baseline phase in clonic or tonic-clonic seizure frequency over the last 4 weeks of fixed-dose treatment [target phase]). Safety and pharmacokinetics were also assessed. Key findings: Of 27 patients screened in the baseline phase, 24 patients entered the dose-adjustment phase. All patients completed the study. Responder rate was 66.7% (16/24, 95% CI: 44.7-84.4%), and four patients became free from clonic or tonic-clonic seizures. The duration of clonic or tonic-clonic seizures was also significantly reduced in the target versus baseline phase. The most frequent adverse events were somnolence, anorexia, ataxia, nasopharyngitis and γ-glutamyl transpeptidase increase, all of which were of mild-to-moderate severity. Stiripentol plasma concentration in the fixed-dose phase was 4-25. μg/mL. After adding stiripentol to CLB and VPA, the minimum plasma concentrations of CLB and N-desmethyl-CLB (NCLB) increased and that of 4'-hydroxy-N-desmethyl-CLB(OH-NCLB) decreased, while those of VPA and bromide (optionally used) were not affected. Significance: Add-on stiripentol to CLB and VPA was well tolerated and significantly decreased clonic or tonic-clonic seizures in patients with Dravet syndrome. © 2014 Elsevier B.V.
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Molecular Genetics and Metabolism Reports 1(1) 133-138 2014年 査読有りLarge numbers of genes are responsible for Leigh syndrome (LS), making genetic confirmation of LS difficult. We screened our patients with LS using a limited set of 21 primers encompassing the frequently reported gene for the respiratory chain complexes I (ND1-ND6, and ND4L), IV(SURF1), and V(ATP6) and the pyruvate dehydrogenase E1α-subunit. Of 18 LS patients, we identified mutations in 11 patients, including 7 in mDNA (two with ATP6), 4 in nuclear (three with SURF1). Overall, we identified mutations in 61% of LS patients (11/18 individuals) in this cohort. Sanger sequencing with our limited set of primers allowed us a rapid genetic confirmation of more than half of the LS patients and it appears to be efficient as a primary genetic screening in this cohort. © 2014 The Authors. Published by Elsevier Inc.
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JIMD reports 12 65-69 2014年 査読有り
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PEDIATRIC NEUROLOGY 50(1) 99-100 2014年1月 査読有りINTRODUCTION: Glucose transporter type 1 deficiency syndrome is a metabolic encephalopathy that results from impaired glucose transport into the brain as the result of a mutation of the SLC2A1 gene. It has been recognized recently that these patients can present with a much broader clinical spectrum than previously thought. We describe a 3-year-old boy presenting with episodic ataxia. CASE REPORT: Our patient exhibited periodic abnormal eye movements, including opsoclonus, since he was 4 months of age. At 2 years of age, he experienced acute cerebellar ataxia after a vaccination. Since then, he has had periodic attacks of ataxic gait, repeated vomiting, and abnormal eye movement. He was diagnosed as having episodic ataxia type 2 because the administration of acetazolamide seemed effective. By 3 years and 10 months of age, he exhibited mild mental retardation and mild trunk ataxia. The attacks were more likely to occur when he was hungry. Molecular analysis revealed that the SLC2A1 gene had a de novo mutation of heterozygous seven nucleotide insertion within exon 7, resulting in a frameshift. He has recently begun a modified Atkins diet; the frequency of attacks has been reduced, and his psychomotor and language skills have begun to develop. DISCUSSION: Glucose transporter type 1 deficiency syndrome should be considered in the differential diagnosis in children with episodic ataxia, even if acetazolamide is effective.
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Clinical Neurology 54(3) 200-206 2014年 査読有りA 35-year-old woman was admitted with subacute intellectual deterioration. Laboratory studies showed elevated total homocysteine and decreased folic acid. MRI revealed leukoencephalopathy with a posterior predominance, and hyperintensity in the pyramidal tracts on T2-weighted and FLAIR images. The enzyme assay showed a deficiency of methylenetetrahydrofolate reductase (MTHFR) activity with low residual activity of 4.2% of the mean control value in cultured fibroblasts. Sequence analysis of the MTHFR gene demonstrated two homozygous missense mutations, c.677C> T (p.Ala222Val) and c.685A> C (p.Ile225Leu). c.677C> T (p.Ala222Val) is known as a common polymorphism and c.685A> C (p.Ile225Leu) is considered to be a novel polymorphism. A diagnosis of MTHFR deficiency was made. Treatment with folic acid, vitamin B12 and B6 made significant improvement of intellectual deterioration and reduction in the total homocysteine level. They also made marked resolution of leukoencephalopathy. Posterior-predominant leukoencephalopathy was found to be an excellent marker of MTHFR deficiency, and may help to establish the diagnosis.
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PEDIATRIC NEUROLOGY 49(6) 477-481 2013年12月 査読有りBACKGROUND: Proteolipid protein 1 gene (PLP1) mutations result in a continuum of neurological findings characterized by X-linked hypomyelinating leukodystrophies of the central nervous system, from mild spastic paraplegia type 2 to severe Pelizaeus Merzbacher disease. PATIENTS: We report spastic paraplegia type 2 in three individuals in one family. A 29-year-old man developed progressive spastic quadriplegia from early childhood with dysarthria, ataxia, dysphagia, and intellectual delay, but he displayed no nystagmus. His mother developed adult-onset mild spastic diplegia with dementia developing in later life, whereas his sister exhibited spastic diplegia from childhood, complicated by motor developmental delay and dysphagia. All three individuals had initially mild but progressive neurological phenotypes, no nystagmus, normal brainstem auditory-evoked potentials, and demyelinating peripheral neuropathy, but with varying clinical severity. RESULTS: A 33-kb deletion encompassing exon 2 to 7 of PLP1 was identified in all three patients. Cloning of the junction fragment of the genomic recombination revealed a short palindromic sequence at the distal breakpoint, potentially facilitating a double-strand deoxyribonucleic acid break, followed by nonhomologous end joining. X-inactivation study and sequencing of the undeleted PLP1 alleles failed to explain the differences in severity between the two female patients. CONCLUSIONS: PLP1 partial deletion is a rare cause of spastic paraplegia type 2 and exhibits X-linked dominant inheritance with variable expressivity.
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HUMAN MUTATION 34(12) 1708-1714 2013年12月 査読有りEarly-onset epileptic encephalopathies (EOEE) are severe neurological disorders characterized by frequent seizures accompanied by developmental regression or retardation. Whole-exome sequencing of 12 patients together with five pairs of parents and subsequent Sanger sequencing in additional 328 EOEE patients identified two de novo frameshift and one missense mutations in SLC35A2 at Xp11.23, respectively. The three patients are all females. X-inactivation analysis of blood leukocyte DNA and mRNA analysis using lymphoblastoid cells derived from two patients with a frameshift mutation indicated that only the wild-type SLC35A2 allele was expressed in these cell types, at least in part likely as a consequence of skewed X-inactivation. SLC35A2 encodes a UDP-galactose transporter (UGT), which selectively supplies UDP-galactose from the cytosol to the Golgi lumen. Transient expression experiments revealed that the missense mutant protein was correctly localized in the Golgi apparatus. In contrast, the two frameshift mutant proteins were not properly expressed, suggesting that their function is severely impaired. Defects in the UGT can cause congenital disorders of glycosylation. Of note, no abnormalities of glycosylation were observed in three serum glycoproteins, which is consistent with favorably skewed X-inactivation. We hypothesize that a substantial number of neurons might express the mutant SLC35A2 allele and suffer from defective galactosylation, resulting in EOEE. (C) 2013 Wiley Periodicals, Inc.
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NEUROGENETICS 14(3-4) 225-232 2013年11月 査読有りCerebellar and/or vermis atrophy is recognized in various types of childhood disorders with clinical and genetic heterogeneity. Although careful evaluation of clinical features and neuroimaging can lead to correct diagnosis of disorders, their diagnosis is sometimes difficult because clinical features can overlap with each other. In this study, we performed family-based whole exome sequencing of 23 families including 25 patients with cerebellar and/or vermis atrophy in childhood, who were unable to be diagnosed solely by clinical examination. Pathological mutations of seven genes were found in ten patients from nine families (9/23, 39.1 %): compound heterozygous mutations in FOLR1, C5orf42, POLG, TPP1, PEX16, and de novo mutations in CACNA1A, and ITPR1. Patient 1A with FOLR1 mutations showed extremely low concentration of 5-methyltetrahydrofolate in the cerebrospinal fluid and serum, and Patient 6 with TPP1 mutations demonstrated markedly lowered tripeptidyl peptidase 1 activity in leukocytes. Furthermore, Patient 8 with PEX16 mutations presented a mild increase of very long chain fatty acids in the serum as supportive data for genetic diagnosis. The main clinical features of these ten patients were nonspecific and mixed, and included developmental delay, intellectual disability, ataxia, hypotonia, and epilepsy. Brain MRI revealed both cerebellar and vermis atrophy in eight patients (8/10, 80 %), vermis atrophy/hypoplasia in two patients (2/10, 20 %), and brainstem atrophy in one patient (1/10, 10 %). Our data clearly demonstrate the utility of whole exome sequencing for genetic diagnosis of childhood cerebellar and/or vermis atrophy.
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PEDIATRIC RADIOLOGY 43(10) 1400-1403 2013年10月 査読有りA stroke-like episode is a core symptom in mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes (MELAS). Proton magnetic resonance spectroscopy (H-1-MRS) is useful in the diagnosis of mitochondrial diseases. We report an 8-year-old girl with MELAS, presenting with a seizure and blindness. H-1-MRS showed a strikingly elevated lactate peak in the right occipital region, where no abnormal signals appeared on either T2-W or diffusion-weighted MRI. She recovered completely within a day. We describe this mild clinical condition with abnormal lactate peak in normal-appearing gray matter as a transient ischemic attack-like episode in MELAS.
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American journal of human genetics 93(3) 496-505 2013年9月5日 査読有り
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NEUROLOGY 81(11) 992-998 2013年9月 査読有りObjective: We aimed to investigate the possible association between SCN2A mutations and early-onset epileptic encephalopathies (EOEEs). Methods: We recruited a total of 328 patients with EOEE, including 67 patients with Ohtahara syndrome (OS) and 150 with West syndrome. SCN2A mutations were examined using high resolution melt analysis or whole exome sequencing. Results: We found 14 novel SCN2A missense mutations in 15 patients: 9 of 67 OS cases (13.4%), 1 of 150 West syndrome cases (0.67%), and 5 of 111 with unclassified EOEEs (4.5%). Twelve of the 14 mutations were confirmed as de novo, and all mutations were absent in 212 control exomes. A de novo mosaic mutation (c.3976G>C) with a mutant allele frequency of 18% was detected in one patient. One mutation (c.634A>G) was found in transcript variant 3, which is a neonatal isoform. All 9 mutations in patients with OS were located in linker regions between 2 transmembrane segments. In 7 of the 9 patients with OS, EEG findings transitioned from suppression-burst pattern to hypsarrhythmia. All 15 of the patients with novel SCN2A missense mutations had intractable seizures; 3 of them were seizure-free at the last medical examination. All patients showed severe developmental delay. Conclusions: Our study confirmed that SCN2A mutations are an important genetic cause of OS. Given the wide clinical spectrum associated with SCN2A mutations, genetic testing for SCN2A should be considered for children with different epileptic conditions.
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NEUROPEDIATRICS 44(4) 199-202 2013年8月 査読有りIn this study, we report the case of an 8-year-old girl who had three episodes of reversible splenial lesion of the corpus callosum (SCC) in 2 years. Vomiting, hypoglycemia, and fever were followed by altered consciousness and diminished muscle tone. In each episode, the clinical manifestations and abnormalities detected during magnetic resonance imaging resolved in 2 weeks. Transient alteration of vision and spike discharges revealed by interictal electroencephalogram implied the SCC lesions were related to epileptic activities. At follow-up, the patient had not presented with SCC lesions or altered consciousness for more than 4 years after undergoing carbamazepine treatment. Our case is the first report of a patient who presented with three episodes of reversible splenial lesion.
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AMERICAN JOURNAL OF HUMAN GENETICS 93(1) 6-18 2013年7月 査読有りNemaline myopathy (NEM) is a common congenital myopathy. At the very severe end of the NEM clinical spectrum are genetically unresolved cases of autosomal-recessive fetal akinesia sequence. We studied a multinational cohort of 143 severe-NEM-affected families lacking genetic diagnosis. We performed whole-exome sequencing of six families and targeted gene sequencing of additional families. We identified 19 mutations in KLHL40 (kelch-like family member 40) in 28 apparently unrelated NEM kindreds of various ethnicities. Accounting for up to 28% of the tested individuals in the Japanese cohort, KLHL40 mutations were found to be the most common cause of this severe form of NEM. Clinical features of affected individuals were severe and distinctive and included fetal akinesia or hypokinesia and contractures, fractures, respiratory failure, and swallowing difficulties at birth. Molecular modeling suggested that the missense substitutions would destabilize the protein. Protein studies showed that KLHL40 is a striated-muscle-specific protein that is absent in KLHL40-associated NEM skeletal muscle. In zebrafish, klhl40a and klhl40b expression is largely confined to the myotome and skeletal muscle, and knockdown of these isoforms results in disruption of muscle structure and loss of movement. We identified KLHL40 mutations as a frequent cause of severe autosomal-recessive NEM and showed that it plays a key role in muscle development and function. Screening of KLHL40 should be a priority in individuals who are affected by autosomal-recessive NEM and who present with prenatal symptoms and/or contractures and in all Japanese individuals with severe NEM.
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脳と発達 45(Suppl.) S226-S226 2013年5月
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Brain and Development 35(4) 312-316 2013年4月 査読有りWe diagnosed three siblings from consanguineous east Asian parents with leukoencephalopathy with brainstem and spinal cord involvement and high lactate (LBSL) from characteristic MRI, MRS findings and a homozygous mutation in the DARS2 gene. The neurological symptoms of the three patients consisted of psychomotor developmental delay, cerebellar ataxia since infancy, spasticity in the initial phase and peripheral neuropathy in later stages. Their mental development was delayed, but did not deteriorate. MRI signal abnormalities included the same abnormalities reported previously but tended to be more extensive. Signal abnormalities in the cerebral and cerebellar white matter were homogeneous and confluent from early stages. In addition, other tract such as the central tegmental tract was involved. Furthermore, an atrophic change in the cerebral white matter was observed on follow-up in one case. Two of the patients were autopsied and neuropathological findings revealed characteristic vacuolar changes in the white matter of the cerebrum, cerebellum and the nerve tracts of the brain stem and spinal cord. The central myelin sheath showed intralamellar splitting by electron microscopy. These findings were consistent to a spongy degeneration in the diffuse white matter of the brain, or spongiform leukoencephalopathy. In addition, peripheral nerves showed both axonal degeneration and abnormal myelin structures. We discussed the relationship between deficits in mitochondrial aspartyl-tRNA synthetase activity and the neuropathology observed. © 2012 The Japanese Society of Child Neurology.
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脳と発達 45(2) 127-131 2013年3月1日髄鞘の構成成分のうち, 最も量的に豊富な蛋白はプロテオリピドプロテイン (proteolipid protein 1; PLP1) であり, この蛋白をコードするPLP1が先天性白質形成不全症の主要疾患, Pelizaeus-Merzbacher病 (PMD) の原因である. 典型例の診断は比較的容易であるが, 軽症群では, 眼振が目立たず, 単に発達遅滞あるいは痙性麻痺と診断されており, MRI検査からPLP1異常が疑われて診断がつく場合も多い. また, PMD以外にも新しい白質形成不全症が次々と明らかになってきている. これらの実例を自験例から紹介しながら, この20年の進歩を概観し, 最後に幹細胞移植治療について触れる.
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No to hattatsu = Brain and development 45(2) 122-126 2013年3月 査読有り先天性大脳白質形成不全症は, 中枢神経系の髄鞘形成不全を主体とする疾患の総称である. その代表的疾患であるPelizaeus-Merzbacher病 (PMD) はX染色体上に存在するPLP1遺伝子の変異によって起こる. 本稿では, まず, 最も頻度の高いPLP1重複が見いだされた経緯とその後の遺伝子診断やゲノム機序の解明に至る経過について概説する. 次に, 小胞体ストレスという細胞病態を標的としたPMDの治療法開発研究の現在の取り組みについて紹介する. 最後に, 先天性大脳白質形成不全症の疾患分類や全国疫学調査の概要などの臨床的基盤研究と今後の展望について述べる.
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脳と発達 45(1) 53-57 2013年1月けいれんで発症し、精神症状や不随意運動を呈し、血液および髄液から抗NMDA受容体抗体が検出され、非腫瘍性抗NMDA受容体抗体脳炎と診断した8歳男児の症例を報告した。急性期のステロイドパルス療法やガンマグロブリン療法は効果がなかったが、月1回合計3クールのcyclophosphamide(CPA)のパルス療法(500mg/m2)後から髄液NMDA抗体価と平行して、症状が急速に改善し始め、発症6ヵ月後に明らかな神経学的合併症なく治癒した。CPA療法は、本症の小児における免疫抑制療法として、ステロイド療法やガンマグロブリン療法とともに考慮されるべき治療である。(著者抄録)
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Journal of Medical Genetics 50(7) 463-472 2013年 査読有りBackground: Creatine transporter deficiency is a monogenic cause of X-linked intellectual disability. Since its first description in 2001 several case reports have been published but an overview of phenotype, genotype and phenotype-genotype correlation has been lacking. Methods: We performed a retrospective study of clinical, biochemical and molecular genetic data of 101 males with X-linked creatine transporter deficiency from 85 families with a pathogenic mutation in the creatine transporter gene (SLC6A8). Results and conclusions: Most patients developed moderate to severe intellectual disability mild intellectual disability was rare in adult patients. Speech language development was especially delayed but almost a third of the patients were able to speak in sentences. Besides behavioural problems and seizures, mild to moderate motor dysfunction, including extrapyramidal movement abnormalities, and gastrointestinal problems were frequent clinical features. Urinary creatine to creatinine ratio proved to be a reliable screening method besides MR spectroscopy, molecular genetic testing and creatine uptake studies, allowing definition of diagnostic guidelines. A third of patients had a de novo mutation in the SLC6A8 gene. Mothers with an affected son with a de novo mutation should be counselled about a recurrence risk in further pregnancies due to the possibility of low level somatic or germline mosaicism. Missense mutations with residual activity might be associated with a milder phenotype and large deletions extending beyond the 30 end of the SLC6A8 gene with a more severe phenotype. Evaluation of the biochemical phenotype revealed unexpected high creatine levels in cerebrospinal fluid suggesting that the brain is able to synthesise creatine and that the cerebral creatine deficiency is caused by a defect in the reuptake of creatine within the neurones.
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Journal of Pediatric Epilepsy 2(4) 255-258 2013年 査読有りTreatment of west syndrome in patients with tuberous sclerosis, the relevant effective period and doses of vigabatrin (VGB) to avoid serious side effects still needs further investigation. We report on a Japanese girl who showed good results with a very low dose of VGB. Tonic spasms appeared at 5 mo of age. Adrenocorticotropic hormone therapy resulted in incomplete seizure control. VGB at the lowest practical dose (30 mg/kg/d) showed complete control after 3 d. With reduction of the dose to 10 mg/kg/d, side effects such as hyperactivity, irritability, and sleep disturbances improved. She was seizure-free for the next 6 mo with an improved developmental quotient. Ophthalmological evaluation revealed no abnormality. The present case illustrates that low-dose VGB therapy (10 mg/kg/d) has fewer side effects and may bring prompt seizure control in west syndrome with tuberous sclerosis. © 2013 - IOS Press and the authors.
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ANNALS OF NEUROLOGY 73(1) 48-57 2013年1月 査読有りObjective: Recently, COL4A1 mutations have been reported in porencephaly and other cerebral vascular diseases, often associated with ocular, renal, and muscular features. In this study, we aimed to clarify the phenotypic spectrum and incidence of COL4A1 mutations. ' Methods: We screened for COL4A1 mutations in 61 patients with porencephaly and 10 patients with schizencephaly, which may be similarly caused by disturbed vascular supply leading to cerebral degeneration, but can be distinguished depending on time of insult. Results: COL4A1 mutations were identified in 15 patients (21%, 10 mutations in porencephaly and 5 mutations in schizencephaly), who showed a variety of associated findings, including intracranial calcification, focal cortical dysplasia, pontocerebellar atrophy, ocular abnormalities, myopathy, elevated serum creatine kinase levels, and hemolytic anemia. Mutations include 10 missense, a nonsense, a frameshift, and 3 splice site mutations. Five mutations were confirmed as de novo events. One mutation was cosegregated with familial porencephaly, and 2 mutations were inherited from asymptomatic parents. Aberrant splicing was demonstrated by reverse transcriptase polymerase chain reaction analyses in 2 patients with splice site mutations. Interpretation: Our study first confirmed that COL4A1 mutations are associated with schizencephaly and hemolytic anemia. Based on the finding that COL4A1 mutations were frequent in patients with porencephaly and schizencephaly, genetic testing for COL4A1 should be considered for children with these conditions. ANN NEUROL 2013;73:48-57
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AMERICAN JOURNAL OF MEDICAL GENETICS PART A 161A(1) 203-207 2013年1月 査読有りWe reported on a male patient with rare leukoencephalopathy and skeletal abnormalities. The condition was first noticed as a developmental delay, nystagmus and ataxia at 1 year of age. At 4 years of age, he was diagnosed as hypomyelination with skeletal abnormalities from clinical features, brain magnetic resonance imaging (MRI) and skeletal X-rays. His brain MRI revealed diffuse hypomyelination. These findings suggested the classical type of PelizaeusMerzbacher disease (PMD) caused by proteolipid protein (PLP)-1 gene or PelizaeusMerzbacher-like disease (PMLD). However, we found neither mutation nor duplication of PLP-1. The patient had severe growth retardation and general skeletal dysplasia compatible with spondylo-epi-metaphyseal dysplasia; however the mutation of discoidin domain receptor (DDR) 2 gene was absent. The co-morbidity of hypomyelination with skeletal abnormalities is rare. We performed array CGH and no causal copy number variation was recognized. Alternatively, this condition may have been caused by a mutation of the gene encoding a molecule that functions in both cerebral myelination and skeletal development. (c) 2012 Wiley Periodicals, Inc.
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No To Hattatsu 45(1) 53-57 2013年1月 査読有りWe report on an 8-year-old boy with non-paraneoplastic anti-NMDA receptor (NMDAR) encephalitis, who presented with psychotic symptoms and involuntary movement following an intractable seizure. His serum and CSF tested positive for anti-NMDAR antibodies. He received an initial immunotherapy consisting of methylprednisolone pulse therapy (mPSL) and intravenous immunoglobulin therapy (IVIg), without any clinical improvement. He had three cycles of monthly cyclophosphamide pulse therapy (500 mg/m2), and his clinical condition started to improve gradually two weeks after the first cycle, without any side effects. Six months after onset, he tested normal upon standard neurological examination. Cyclophosphamide therapy should be considered for children with anti-NMDAR encephalitis, as well as mPSL and IVIg.
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MAGNETIC RESONANCE IMAGING 30(10) 1527-1533 2012年12月 査読有りBackground and Purpose: Influenza viral infection, which results in central nervous system dysfunction, is a major cause of acute encephalopathy (AE). The purpose of this study was to investigate the changes in the concentrations of brain metabolites in children with AE using single-voxel magnetic resonance spectroscopy (MRS) and to provide diagnostic information about the relationship between the symptoms of AE and metabolite concentrations. Materials and Methods: The subjects were 10 children (mean age: 6.2 years; range: 1-13) with AE caused by the novel influenza A virus responsible for the 2009 influenza pandemic. The serial MRS data (TE/TR=30/5000 ms, 3 T) acquired from the basal ganglia (BG) and centrum semiovale (CS) of each patient were categorized into three periods: (1) initial neurological symptom presentation and the start of treatment (n=10), (2) short-term follow-up (n=9) and (3) long-term follow-up (n=3). As controls, the magnetic resonance (MR) spectra of eight age-matched children were also investigated. Results: In both regions, the concentrations of the major metabolites (N-acetylaspartate, creatine, choline, myo-inositol, glutamate/glutamine complex and glutamate) only showed minor fluctuations between the three periods. On the other hand, higher levels of taurine (Tau) were observed in the BG during the second period (P=.005), and increased levels of glucose were observed in the CS during the first (P=.005) and second (P=.036) periods. Conclusions: Serial monitoring of brain metabolite changes was carried out with a clinical MR system. The concentrations of major metabolites only displayed very minor fluctuations in response to mild H1N1-related AE. However, a higher Tau concentration was found to be associated with neurological symptoms. Further studies are required to improve our understanding of the detailed activity of Tau in AE. (C) 2012 Elsevier Inc. All rights reserved.
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BRAIN & DEVELOPMENT 34(10) 861-865 2012年11月 査読有りWe report two patients with Leigh syndrome that showed a combination of facial dysmorphism and MRI imaging indicating an SURF1 deficiency, which was confirmed by sequence analysis. Case 1 is a 3-year-old girl with failure to thrive and developmental delay. She presented with tachypnea at rest and displayed facial dysmorphism including frontal bossing, lateral displacement of inner canthi, esotropia, maxillary hypoplasia, slightly upturned nostril, and hypertrichosis dominant on the forehead and extremities. Case 2 is an 8-year-old boy with respiratory failure. He had been diagnosed as selective complex IV deficiency. Case 2 displayed facial dysmorphism and hypertrichosis. Since both patients displayed characteristic facial dysmorphism and MRI findings, we sequenced the SURF1 gene and identified two heterozygous mutations; c.49+1 G>T and c.752_753del in Case I, and homozygous c.743 C>A in Case 2. For patients with Leigh syndrome showing these facial dysmorphism and hypertrichosis, sequence analysis of the SURF1 gene may be useful. (C) 2012 The Japanese Society of Child Neurology. Published by Elsevier B.V. All rights reserved.
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日本臨床 別冊(先天代謝異常症候群(上)) 289-292 2012年10月
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PEDIATRIC NEUROLOGY 47(3) 198-200 2012年9月 査読有りA 4-year-old boy presented with a sudden onset of nasal escape of fluids, nasal speech, and difficulty placing his left arm through a sleeve. Neurologic examination indicated a unilateral cranial IX and X and contralateral XI nerve palsy that was considered idiopathic. Palsy of cranial nerves IX, X, and XI is rare in childhood, and few reports have described this condition. Our patient received prednisolone for 1 week and demonstrated complete recovery within several weeks. We suggest that aggressive therapy is unnecessary for patients with idiopathic cranial polyneuropathy. The pathogenesis of this condition may involve an immunologic mechanism. (C) 2012 Elsevier Inc. All rights reserved.
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AMINO ACIDS 43(2) 993-997 2012年8月 査読有りCerebral creatine deficiency syndromes (CCDS) are caused by genetic defects in l-arginine:glycine amidinotransferase, guanidinoacetate methyltransferase or creatine transporter 1. CCDS are characterized by abnormal concentrations of urinary creatine (CR), guanidinoacetic acid (GA), or creatinine (CN). In this study, we describe a simple HPLC method to determine the concentrations of CR, GA, and CN using a weak-acid ion chromatography column with a UV detector without any derivatization. CR, GA, and CN were separated clearly with the retention times (mean +/- A SD, n = 3) of 5.54 +/- A 0.0035 min for CR, 6.41 +/- A 0.0079 min for GA, and 13.53 +/- A 0.046 min for CN. This new method should provide a simple screening test for the diagnosis of CCDS.
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EPILEPSIA 53(8) 1441-1449 2012年8月 査読有りPurpose: Ohtahara syndrome (OS) is one of the most severe and earliest forms of epilepsy. STXBP1 and ARX mutations have been reported in patients with OS. In this study, we aimed to identify new genes involved in OS by copy number analysis and whole exome sequencing. Methods: Copy number analysis and whole exome sequencing were performed in 34 and 12 patients with OS, respectively. Fluorescence in situ hybridization, quantitative polymerase chain reaction (PCR), and breakpoint-specific and reverse-transcriptase PCR analyses were performed to characterize a deletion. Immunoblotting using lymphoblastoid cells was done to examine expression of CASK protein. Key Findings: Genomic microarray analysis revealed a 111-kb deletion involving exon 2 of CASK at Xp11.4 in a male patient. The deletion was inherited from his mother, who was somatic mosaic for the deletion. Sequencing of the mutant transcript expressed in lymphoblastoid cell lines derived from the patient confirmed the deletion of exon 2 in the mutant transcript with a premature stop codon. Whole exome sequencing identified another male patient who was harboring a c.1A>G mutation in CASK, which occurred de novo. Both patients showed severe cerebellar hypoplasia along with other congenital anomalies such as micrognathia, a high arched palate, and finger anomalies. No CASK protein was detected by immuno-blotting in lymphoblastoid cells derived from two patients. Significance: The detected mutations are highly likely to cause the loss of function of the CASK protein in male individuals. CASK mutations have been reported in patients with intellectual disability with microcephaly and pontocerebellar hypoplasia or congenital nystagmus, and those with FG syndrome. Our data expand the clinical spectrum of CASK mutations to include OS with cerebellar hypoplasia and congenital anomalies at the most severe end.
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Nucleic acids research 40(12) 5389-5401 2012年7月 査読有り
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BRAIN & DEVELOPMENT 34(5) 364-367 2012年5月 査読有りRecent studies have shown that aberrations of CDKL5 in female patients cause early-onset intractable seizures, severe developmental delay or regression, and Rett syndrome-like features. We report on a Japanese girl with early-onset epileptic encephalopathy, hypotonia, developmental regression, and Rett syndrome-like features. The patient showed generalized tonic seizures, and later, massive myoclonus induced by phone and light stimuli. Brain magnetic resonance imaging showed no structural brain anomalies but cerebral atrophy. Electroencephalogram showed frontal dominant diffuse poly spikes and waves. Through copy number analysis by genomic microarray, we found a microdeletion at Xp22.13. A de novo 137-kb deletion, involving exons 5-21 of CDKL5, RS1, and part of PPEF1 gene, was confirmed by quantitative PCR and breakpoint specific PCR analyses. Our report suggests that the clinical features associated with CDKL5 deletions could be implicated in Japanese patients, and that genetic testing of CDKL5, including both sequencing and deletion analyses, should be considered in girls with early-onset epileptic encephalopathy and RTT-like features. (C) 2011 The Japanese Society of Child Neurology. Published by Elsevier B.V. All rights reserved.
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MOLECULAR GENETICS AND METABOLISM 106(1) 108-114 2012年5月 査読有りPLP1 amino acid substitutions cause accumulation of misfolded protein and induce endoplasmic reticulum (ER) stress, causing Pelizaeus-Merzbacher disease (PMD), a hypomyelinating disorder of the central nerve system. Currently no effective therapy is available for PMD. Promoted by its curative effects in other genetic disease models caused by similar molecular mechanisms, we tested if curcumin, a dietary compound, can rescue the lethal phenotype of a PMD mouse model (myelin synthesis deficient, msd). Curcumin was administered orally to myelin synthesis deficit (msd) mice at 180 mg.kg(-1)day(-1) from the postnatal day 3. We evaluated general and motor status, changes in myelination and apoptosis of oligodendrocytes by neuropathological and biochemical examination, and transcription levels for ER-related molecules. We also examined the pharmacological effect of curcumin in cell culture system. Oral curcumin treatment resulted in 25% longer survival (p<0.01). In addition, oligodendrocytes undergoing apoptosis were reduced in number (p<0.05). However, no apparent improvement in motor function, neurological phenotype, and myelin formation was observed. Curcumin treatment did not change the expression of ER stress markers and subcellular localization of the mutant protein in vitro and/or in vivo. Curcumin partially mitigated the clinical and pathological phenotype of msd mice, although molecular mechanisms underlying this curative effect are yet undetermined. Nonetheless, curcumin may serve as a potential therapeutic compound for PMD caused by PLP1 point mutations. (C) 2012 Elsevier Inc. All rights reserved.
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Contiguous deletion of SLC6A8 and BAP31 in a patient with severe dystonia and sensorineural deafnessMOLECULAR GENETICS AND METABOLISM 106(1) 43-47 2012年5月 査読有りWe report here a 6-year-old boy exhibiting severe dystonia, profound intellectual and developmental disability with liver disease, and sensorineural deafness. A deficient creatine peak in brain H-1-MR spectroscopy and high ratio of creatine/creatinine concentration in his urine lead us to suspect a creatine transporter (solute carrier family 6, member 8; SLC6A8) deficiency, which was confirmed by the inability to take up creatine into fibroblasts. We found a large similar to 19 kb deletion encompassing exons 5-13 of SLC6A8 and exons 5-8 of the B-cell receptor-associated protein (BAP31) gene. This case is the first report in which the SLC6A8 and BAP31 genes are both deleted. The phenotype of BAP31 mutations has been reported only as a part of Xq28 deletion syndrome or contiguous: ATP-binding cassette, sub-family D, member 1 (ABCD1)/DXS1375E (BAP31) deletion syndrome [MIM ID #300475], where liver dysfunction and sensorineural deafness have been suggested to be attributed to the loss of function of BAP31. Our case supports the idea that the loss of BAP31 is related to liver dysfunction and hearing loss. (C) 2012 Elsevier Inc. All rights reserved.
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ACTA RADIOLOGICA 53(2) 223-227 2012年3月 査読有りThe changes in the signals for brain metabolites in the left cerebellum of a 14-year-old boy with acute hemicerebellitis were monitored using proton magnetic resonance spectroscopy (MRS). From the onset of disease treatment to long-term follow-up, MRS data were serially acquired from the left and right cerebella, basal ganglia (BG), and centrum semiovale (CS). Large fluctuations in his MRS signals were observed in the left cerebellum. At onset (first day), his glutamate/glutamine complex signals were increased (>mean +/- 2 standard deviations [SD] of the control), and those for N-acetylaspartate/N-acetylaspartylglutamate and myo-inositol were decreased (<2SD). By the 25th day, these signals had recovered to normal levels, while those for choline (Cho) were increased. In other locations, the signals for mins in the BG and Cho in the CS were decreased on the seventh day. By the 201st day, the levels of all metabolites in all locations had recovered to within +/- 2SD of the control levels. In vivo proton MRS monitoring demonstrated reversible metabolite changes associated with acute hemicerebellitis, which should contribute to its differential diagnosis from brain tumors.
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BRAIN & DEVELOPMENT 34(1) 72-75 2012年1月 査読有りNonketotic hyperglycinemia (NKH), or glycine encephalopathy, is an autosomal recessive disorder caused by a defect in the glycine cleavage enzyme system. In neonatal-onset NKH, patients manifest lethargy, hypotonia, apnea, and intractable epileptic seizures that are not specific to this disease. We experienced a 6-year-old girl with spastic quadriplegia, intractable epilepsy, and mental retardation, all initially regarded as sequelae of neonatal meningitis. The seizure frequency was transiently increased when valproate was started. Head MRI revealed progressive brain atrophy and white matter loss with high intensity signals on T2-weighted and diffusion-weighted images, which prompted us to conduct further metabolic workups. High glycine levels led us to suspect NKH, and we confirmed this diagnosis by the non-invasive, C-13-glycine breath test. DNA sequencing revealed novel Leu885Pro/Trp897Cys mutations in the glycine decarboxylase gene that were transmitted from both parents. Sodium benzoate and dextromethorphan dramatically decreased her hypertonicity. Our case shows that paradoxical increases in seizure frequency following valproate can be a clue for a diagnosis of NKH, and that a correct diagnosis of NKH can greatly alter the quality of life in such patients. (C) 2011 The Japanese Society of Child Neurology. Published by Elsevier B.V. All rights reserved.
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AMERICAN JOURNAL OF MEDICAL GENETICS PART A 158A(1) 199-205 2012年1月 査読有りWe report on a female patient with early infantile epileptic encephalopathy and severe psychomotor disability possessing a de novo balanced translocation t(1;9)(q32;q13). The patient showed clonic convulsions of extremities 2 days after birth. Electroencephalogram (EEG) transiently showed atypical suppression-burst pattern. The seizures evolved to brief tonic spasms, and hypsarrhythmia on EEG was noticed at age of 5 months, indicating the transition to West syndrome. By using fluorescent in situ hybridization (FISH), southern hybridization, and inverse PCR, the translocation breakpoints were successfully determined at the nucleotide level. The 1q32.1 breakpoint was located within a segmental duplication and disrupted the gene encoding Slit-Robo Rho GTPase activating protein 2 (SRGAP2). The 9q13 breakpoint was suggested to reside in the heterochromatin region. Srgap2 has been shown to be specifically expressed in developing brain of rodents, negatively regulate neuronal migration and induce neurite outgrowth and branching. Thus, SRGAP2 is very likely to play a role in the developing human brain. This is a first report of the SRGAP2 abnormality associated with early infantile epileptic encephalopathy. (C) 2011 Wiley Periodicals, Inc.
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American journal of human genetics 90(1) 86-90 2012年1月 査読有り
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No To Hattatsu 44(1) 35-40 2012年1月 査読有りWe report 12 cases of acute encephalopathy associated with influenza H1N1-2009 treated according to Japanese guideline (2009). In all 12 cases, electroencephalogram presented diffuse or localized high-amplitude slow waves. Brain CT and MRI showed abnormalities in 4 and 6 cases, respectively. We used hypothermia therapy for 5 patients. One patient showed impairment in short term memory, while the rest of the patients showed no sequelae. These 12 cases presented here suggest the early recognition and therapy according to the newly proposed guideline may reduce severe sequelae and mortality by acute encephalopathy associated with influenza H1N1-2009.
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AMERICAN JOURNAL OF HUMAN GENETICS 89(5) 644-651 2011年11月 査読有りCongenital hypomyelinating disorders are a heterogeneous group of inherited leukoencephalopathies characterized by abnormal myelin formation. We have recently reported a hypomyelinating syndrome characterized by diffuse cerebral hypomyelination with cerebellar atrophy and hypoplasia of the corpus callosum (HCAHC). We performed whole-exome sequencing of three unrelated individuals with HCAHC and identified compound heterozygous mutations in POLR3B in two individuals. The mutations include a nonsense mutation, a splice-site mutation, and two missense mutations at evolutionally conserved amino acids. Using reverse transcription-PCR and sequencing, we demonstrated that the splice-site mutation caused deletion of exon 18 from POLR3B mRNA and that the transcript harboring the nonsense mutation underwent nonsense-mediated mRNA decay. We also identified compound heterozygous missense mutations in POLR3A in the remaining individual. POLR3A and POLR3B encode the largest and second largest subunits of RNA Polymerase III (Pol III), RPC1 and RPC2, respectively. RPC1 and RPC2 together form the active center of the polymerase and contribute to the catalytic activity of the polymerase. Pol III is involved in the transcription of small noncoding RNAs, such as SS ribosomal RNA and all transfer RNAs (tRNA). We hypothesize that perturbation of Pal 111 target transcription, especially of tRNAs, could be a common pathological mechanism underlying POLR3A and POLR3B mutations.
MISC
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Epileptic disorders : international epilepsy journal with videotape 22(2) 214-218 2020年4月16日Ring chromosome 20 syndrome is an epileptic and neurodevelopmental encephalopathy that occurs in children, characterised by a triad of refractory frontal lobe seizures, recurrent non-convulsive status epilepticus and frontal lobe-dominant paroxysmal discharges. However, details of other clinical features associated with ring chromosome 20 syndrome remain unknown. Here, we report two patients with ring chromosome 20 syndrome who had praxis-induced reflex seizures. Case 1 was an 11-year-old girl who presented with seizures triggered by specific activities such as mental and written calculations, writing, decision-making, recall, sudden changes in routine or ambient temperature and bathing. During calculations, left frontal lobe-dominant, 3-Hz slow-wave bursts were observed on EEG. Lacosamide effectively suppressed her tonic seizures. Case 2 was a six-year-old boy who presented with seizures triggered by specific activities such as calculations, recall and bathing. During calculations, frontal lobe-dominant, 3-Hz spike and slow-wave bursts were observed on EEG. Although his epilepsy was refractory, gabapentin reduced the frequency of focal seizures. In both cases, the hyperexcitability in the frontal lobe may have spread to the motor cortex and precipitated praxis-induced seizures. Therefore, in addition to the known characteristic triad, praxis-induced reflex seizures may also be a feature of ring chromosome 20 syndrome.
共同研究・競争的資金等の研究課題
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日本学術振興会 科学研究費助成事業 2022年4月 - 2025年3月
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日本学術振興会 科学研究費助成事業 2020年4月 - 2023年3月
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日本学術振興会 科学研究費助成事業 2016年4月 - 2019年3月
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日本学術振興会 科学研究費助成事業 2015年4月 - 2019年3月
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日本学術振興会 科学研究費助成事業 2014年4月 - 2018年3月