Shuichi Shimakawa

Actin Mutations Are One Cause of Congenital Fibre Type Disproportion

We report three heterozygous missense mutations of the skeletal muscle alpha actin gene (ACTA1) in three unrelated cases of congenital fiber type disproportion (CFTD) from Japan and Australia. This represents the first genetic cause of CFTD to be identified and confirms that CFTD is genetically heterogeneous. The three mutations we have identified Leucine221Proline, Aspartate292Valine, and Proline332Serine are novel. They have not been found previously in any cases of nemaline, actin, intranuclear rod, or rod‐core myopathy caused by mutations in ACTA1. It remains unclear why these mutations cause type 1 fiber hypotrophy but no nemaline bodies. The three mutations all lie on one face of the actin monomer on the surface swept by tropomyosin during muscle activity, which may suggest a common pathological mechanism. All three CFTD cases with ACTA1 mutations had severe congenital weakness and respiratory failure without ophthalmoplegia. There were no clinical features specific to CFTD cases with ACTA1 mutations, but the presence of normal eye movements in a severe CFTD patient may be an important clue for the presence of a mutation in ACTA1. Ann Neurol 2004

Clinical spectrum of SCN2A mutations expanding to Ohtahara syndrome

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.

PCDH19-related female-limited epilepsy: Further details regarding early clinical features and therapeutic efficacy

Abnormalities in the protocadherin 19 (PCDH19) gene cause early-onset epilepsy exclusively in females. We aimed to explore the genetic and clinical characteristics of PCDH19-related epilepsy by focusing on its early features and treatment efficacy. PCDH19 was analyzed in 159 Japanese female patients with early-onset epilepsy via direct sequencing and multiplex ligation-dependent probe amplification (MLPA) analysis. We identified 17 patients with PCDH19 abnormalities: point mutations were observed in 14 patients and whole PCDH19 deletions were detected in 3 patients. One affected sister of a proband with a mild phenotype was also analyzed. The frequency of PCDH19 deletion among all probands identified in Japan was 12.5% (3/24, including 7 probands reported previously by us). Clinical features included early onset (mean age at onset, 8.6 months), recurrent clusters of brief seizures (17/18), fever sensitivity (18/18), tonic seizures (13/18, probably including focal tonic seizures), tonic-clonic seizures (8/18), focal seizures often with subsequent generalization (17/18), intellectual disabilities (15/18), and autistic traits (13/18). Three patients exhibited delay in motor milestones before seizure onset. In 16 patients, seizures appeared in clusters from the onset of the disease. Among 6 patients for whom detailed information at onset was available, 2 onset patterns were identified: a biphasic course of short seizure clusters (each within days) in 2 patients and a prolonged course of clusters (from weeks to a month) in 4 patients. In both cases, initial seizures started during fever and transiently disappeared with the decline of fever; however, afebrile clusters recurred. In the former patients, motor development was delayed before onset, and seizures appeared in strong clusters from the onset of the disease. In the latter patients, initial development was normal and initial seizures were mild, but were followed by strong clusters lasting several weeks, even without fever. Treatment using phenytoin, potassium bromide, and clobazam showed high efficacy. Although focal seizures were the main feature in PCDH19-epilepsy, the efficacy of carbamazepine was poor. This study highlighted the significance of PCDH19 deletion, a unique pattern of initial seizure clusters, and the efficacy of antiepileptic drugs. Our data will facilitate early diagnosis and development of a treatment strategy for better clinical management of patients with PCDH19-related epilepsy.

Edaravone prevents kainic acid-induced neuronal death.

There is growing evidence that free radical generation may play a key role in the neuronal damage induced by prolonged convulsions. Free radical scavengers are known to inhibit neuronal death induced by exposure to excitotoxins. However, this neuroprotective effect has not been demonstrated with treatment after seizures had been stopped. We investigated whether 3-methyl-1-phenyl-2-pyrazolin-5-one, edaravone (Ed), a newly developed free radical scavenger that has been used clinically to treat cerebral infarction, could prevent neuronal loss when administered after the occurrence of seizures in a kainic acid (KA)-induced seizure model. Compared with KA alone, cell loss was significantly reduced when animals received Ed (10 mg/kg i.v.) just after seizures, and when Ed was administered both 60 min before (30 mg/kg i.p.) and after KA injection. Combined before-and-after treatment with Ed significantly ameliorated the KA-induced decrease of glutathione and blocked the KA-induced increase of 4-hydroxy-2-nonenal (HNE). Because before-and-after treatment with Ed significantly lessened the KA-induced increase of HNE, Ed may exert its neuroprotective effect by inhibiting lipid peroxidation. However, post-treatment with Ed prevented neuronal cell loss, while HNE and glutathione levels did not differ from those in animals without Ed, so a mechanism other than free radical scavenging must be involved in the prevention of cell loss. Patients who develop status epilepticus are unlikely to receive adequate antioxidant therapy before the onset, so it is an advantage that Ed can prevent neuronal death even when administered after seizures.

Microarray analysis of 50 patients reveals the critical chromosomal regions responsible for 1p36 deletion syndrome-related complications

OBJECTIVE Monosomy 1p36 syndrome is the most commonly observed subtelomeric deletion syndrome. Patients with this syndrome typically have common clinical features, such as intellectual disability, epilepsy, and characteristic craniofacial features. METHOD In cooperation with academic societies, we analyzed the genomic copy number aberrations using chromosomal microarray testing. Finally, the genotype-phenotype correlation among them was examined. RESULTS We obtained clinical information of 86 patients who had been diagnosed with chromosomal deletions in the 1p36 region. Among them, blood samples were obtained from 50 patients (15 males and 35 females). The precise deletion regions were successfully genotyped. There were variable deletion patterns: pure terminal deletions in 38 patients (76%), including three cases of mosaicism; unbalanced translocations in seven (14%); and interstitial deletions in five (10%). Craniofacial/skeletal features, neurodevelopmental impairments, and cardiac anomalies were commonly observed in patients, with correlation to deletion sizes. CONCLUSION The genotype-phenotype correlation analysis narrowed the region responsible for distinctive craniofacial features and intellectual disability into 1.8-2.1 and 1.8-2.2 Mb region, respectively. Patients with deletions larger than 6.2 Mb showed no ambulation, indicating that severe neurodevelopmental prognosis may be modified by haploinsufficiencies of KCNAB2 and CHD5, located at 6.2 Mb away from the telomere. Although the genotype-phenotype correlation for the cardiac abnormalities is unclear, PRDM16, PRKCZ, and RERE may be related to this complication. Our study also revealed that female patients who acquired ambulatory ability were likely to be at risk for obesity.

Oseltamivir treatment for children showing abnormal behavior during influenza virus infection

UNLABELLED We investigated the clinical courses of children with influenza infection, who showed abnormal behavior, who were treated with oseltamivir (Tamiflu). SUBJECTS The subjects were 22 children, 2-15 (mean+/-SD, 6.6+/-3.2) years old, admitted to our hospital during the 2004-2005, 2005-2006, and 2006-2007 influenza seasons. Abnormal behavior appeared before treatment with oseltamivir in 13 children (pre-Tami group), and after administration of the medication in 9 (post-Tami group). All patients continued to receive oseltamivir for 3-5 days after admission. RESULTS Meaningless speech and movements without a specific purpose were the most frequent abnormal behavior (16 children), while illusions, delusions, and misidentifying awareness were the second most common (14 children). Sensations of marked fear and excitement were recognized in 6 children. One child rushed up and down the stairs unconsciously, raising concern that a serious accident might occur. All patients showed a favorable clinical course, without worsening of neurological symptoms or the development of encephalopathy, and outcomes were good. The clinical course, number of recurrences of abnormal behavior, and outcome were similar in the pre-Tami and post-Tami groups. CONCLUSIONS Our observations suggest that oseltamivir is not a prerequisite for the development of abnormal behavior and does not worsen the clinical manifestations of abnormal behaviors, although further investigations are needed to determine whether oseltamivir is necessary, or even useful, for patients with influenza virus encephalopathy.

Clinical and radiological features of Japanese patients with a severe phenotype due to CASK mutations.

Heterozygous loss of function mutations of CASK at Xp11.4 in females cause severe intellectual disability (ID) and microcephaly with pontine and cerebellar hypoplasia (MICPCH). However, the longitudinal clinical and radiological course of affected patients, including patterns of postnatal growth, has not been described. Neurodevelopmental and imaging information was retrospectively accrued for 16 Japanese (15 female and 1 male) patients with ID and MICPCH associated with CASK mutations. All records were analyzed; patient age ranged from 2 to 16 years at the time of the most recent examinations. The growth pattern, neurological development, neurological signs/symptoms, and facial features were similar in the 15 female patients. Their head circumference at birth was within the normal range in about half, and their height and weight were frequently normal. This was followed by early development of severe microcephaly and postnatal growth retardation. The patients acquired head control almost normally between 3 and 6 months, followed by motor delay. More than half of the female patients had epilepsy. Their MRIs showed microcephaly, brainstem, and cerebellar hypoplasia in early infancy, and a normal or large appearing corpus callosum. The male patient showed a more severe clinical phenotype. These uniform clinical and radiological features should facilitate an early diagnosis and be useful for medical care of females with ID and MICPCH associated with CASK mutations.

Hippocampal damage after prolonged febrile seizure: One case in a consecutive prospective series

The factors that contribute to hippocampal damage as a sequela, and its frequency, in patients experiencing febrile status epilepticus, remain unknown. Of the 472 patients with febrile seizures admitted to our hospital between February 2004 and August 2008, 77 had prolonged seizures. Among them, 59 underwent magnetic resonance imaging (MRI). A 21‐month‐old girl showed hippocampal changes after her first episode of febrile status epilepticus. The seizure lasted about 35 min, with eye deviation to the right and ictal rhythmic discharges in the left hemisphere. MRI at 72 h after the seizure revealed high‐signal intensities in T2 and fluid‐attenuated inversion recovery (FLAIR) images of the left hippocampus. Left hippocampal volume diminished over the next several months suggesting the occurrence of neuronal cell death. In no other cases, not even those with longer seizure durations, did significant hippocampal changes develop. The frequency of hippocampal damage was 1.7% in this case series. The involvement of factors other than seizure duration merits further study.

Clinical trial of minimal treatment for clustering seizures in cases of convulsions with mild gastroenteritis

UNLABELLED The aim of this study was to identify means of shortening the treatment period for clustering seizures in patients with convulsions with mild gastroenteritis (CwG). METHODS Sixty-two episodes in 61 patients who presented with CwG managed with carbamazepine (CBZ) or Lidocaine (Lidocaine tape (LDT) or intravenous infusion (Lid-iv)) between November 2005 and October 2008 were studied. The subjects were divided into the following groups: 33 episodes treated with CBZ-1 (5mg/kg/day, 1 day), 7 with CBZ-3 (5mg/kg/day, 3 days), 11 with LDT-1 (LDT 2 sheets in 24h), 4 with LDT-2 (LDT 2 sheets in 48 h), and 7 with Lid-iv (1mg/kg/h, continuous infusion). RESULTS One to seven seizures were recognized before starting CBZ or Lidocaine therapy, followed by complete cessation in 57 episodes and one or two recurrent seizures in five. Efficacy rates were 97% for CBZ-1, 100% for CBZ-3, 72.7% for LDT-1, 75% for LID-2, and 100% for Lid-iv. Efficacy was significantly higher in the CBZ groups than the Lidocaine groups (p=0.019), while the differences between treatment periods (CBZ-1 vs. CBZ-3, and Lid-1 vs. Lid-2) did not reach statistical significance (p>0.999). CONCLUSIONS CBZ and Lidocaine were effective for treating clustering seizures of CwG. We confirmed that the treatment period can be shortened without loss of efficacy. Therefore, we consider 1 day therapy with CBZ or Lidocaine to be sufficient.

MED13L haploinsufficiency syndrome: A de novo frameshift and recurrent intragenic deletions due to parental mosaicism

MED13L haploinsufficiency syndrome is a clinical condition manifesting intellectual disability and developmental delay in association with various complications including congenital heart defects and dysmorphic features. Most of the previously reported patients showed de novo loss‐of‐function mutations in MED13L. Additional three patients with MED13L haploinsufficiency syndrome were identified here in association with rare complications. One patient had a de novo deletion (c.257delT) and T2‐weighted high intensity in the occipital white matter on magnetic resonance imaging. Two siblings exhibited an intragenic deletion involving exons 3–14, which led to an in‐frame deletion in MED13L. The deletion was inherited from their carrier mother who possessed low frequency mosaicism. The older sister of the siblings showed craniosynostosis; this condition has never been reported in patients with MED13L haploinsufficiency syndrome. Dysmorphic features were observed in these patients; however, most of the findings were nonspecific. Further information would be necessary to understand this clinical condition better.