Molecular analysis of the genes causing recessive demyelinating Charcot-Marie-Tooth disease in Japan.

Charcot-Marie-Tooth disease (CMT), the most common hereditary neuropathy, has been classified into two types, demyelinating and axonal types. We previously analyzed the genes causing dominant demyelinating CMT in 227 Japanese patients to identify the genetic background, but could not find any mutations in 110 patients. To investigate the frequency of patients with autosomal recessive demyelinating CMT (CMT4) mutations, we analyzed the coding sequence of known causative genes of CMT4 in 103 demyelinating CMT patients, excluding seven patients owing to lack of specimens. We found one patient with a GDAP1 mutation, one patient with an MTMR2 mutation, two patients with SH3TC2/KIAA1985 mutations and three patients with FGD4 mutations. Twelve patients, including five previously detected patients with PRX mutations, were diagnosed as CMT4, accounting for 5.5% of demyelinating CMT. In the patient with GDAP1 mutation, only one mutation inherited from his mother was detected by genomic sequencing. Analysis by reverse transcription polymerase chain reaction using messenger RNA (mRNA) from the patient's leukocytes revealed the absence of transcription from the allele inherited from his father, suggesting the existence of one more mutation leading to a lack or destabilization of mRNA. Most patients carrying CMT4 gene mutations present with early-onset and slowly progressive symptoms, which may be associated with the function of mutants. We could not identify the disease-causing gene in 96 patients (about 45%). Further studies including studies with next-generation sequencers will be required to identify the causative gene in Japanese CMT.

Subtelomeric deletions of 1q43q44 and severe brain impairment associated with delayed myelination.

Subtelomeric deletions of 1q44 cause mental retardation, developmental delay and brain anomalies, including abnormalities of the corpus callosum (ACC) and microcephaly in most patients. We report the cases of six patients with 1q44 deletions; two patients with interstitial deletions of 1q44; and four patients with terminal deletions of 1q. One of the patients showed an unbalanced translocation between chromosome 5. All the deletion regions overlapped with previously reported critical regions for ACC, microcephaly and seizures, indicating the recurrent nature of the core phenotypic features of 1q44 deletions. The four patients with terminal deletions of 1q exhibited severe volume loss in the brain as compared with patients who harbored interstitial deletions of 1q44. This indicated that telomeric regions have a role in severe volume loss of the brain. In addition, two patients with terminal deletions of 1q43, beyond the critical region for 1q44 deletion syndrome exhibited delayed myelination. As the deletion regions identified in these patients extended toward centromere, we conclude that the genes responsible for delayed myelination may be located in the neighboring region of 1q43.

Expression of estrogen receptor alpha and beta in reactive astrocytes at the male rat hippocampus after status epilepticus.

Estrogen is neuroprotective against status epilepticus (SE)-induced hippocampal damage in female animals. In male animals, estrogen is converted from testosterone via aromatization the activity of which is upregulated by brain damage. However, it is controversial whether estrogen is neuroprotective or neuroinvasive against male hippocampal damage after SE. In order to understand the role of estrogen, it is important to elucidate the distribution manner of estrogen receptor (ER)alpha and beta as the targets of estrogen. In this study, we examined the time course changes of ERs in adult male rat hippocampus after SE using anti-ERalpha antibodies (MC-20 and PA1-309) and anti-ERbeta antibodies (PA1-310B and PA1-311). In control rats, both ERalpha and beta were expressed in the pyramidal cells predominantly at CA1 and CA3. ERalpha was expressed in the cytoplasm and the nucleus, whereas ERbeta was expressed in the cytoplasm of the pyramidal cells. After SE, according to the pyramidal cell loss at CA1, the number of ERalpha- and beta-immunoreactive pyramidal cells decreased up to day 21. On the other hand, reactive astrocytes, which newly appeared after SE and formed gliosis at CA1, were confirmed to express both ERs in the nucleus, cytoplasm, and process. There were no differences in immunoreactivity between antibodies. Our results indicate that endogenous estrogen affects the pyramidal cells through ERalpha and beta under normal circumstances in adult male rats, whereas the targets of estrogen shift to the reactive astrocytes through ERalpha and beta after SE.

Effectiveness of lidocaine infusion for status epilepticus in childhood: a retrospective multi-institutional study in Japan.

We evaluated the usefulness of intravenous lidocaine therapy for managing of status epilepticus (SE) during childhood in a retrospective multi-institutional study. Questionnaires were sent to 28 hospitals concerning patients admitted for SE who were managed with lidocaine, assessing patient characteristics, treatment protocols and efficacy. In 279 treated patients, 261 SE occurrences at ages between 1 month and 15 years were analyzed. SE was classified as showing continuous, clustered, or frequently repeated seizures. Considering efficacy and side effects in combination, the usefulness of lidocaine was classified into six categories: extremely useful, useful, slightly useful, not useful, associated with deterioration, or unevaluated. In 148 SE cases (56.7%), lidocaine was rated as useful or extremely useful. Multivariate analysis indicated lidocaine was to be useful in SE with clustered and frequently repeated seizures, and SE attributable to certain acute illnesses, such as convulsions with mild gastroenteritis. Efficacy was poor when SE caused by central nervous system (CNS) infectious disease. Standard doses (approximately 2mg/kg as a bolus, 2mg/kg/h as maintenance) produced better outcomes than lower or higher doses. Poor responders to the initial bolus injection of lidocaine were less likely to respond to subsequent continuous infusion than good initial responders. We recommend lidocaine for use in SE with clustered or frequently repeated seizures, and in SE associated with benign infantile convulsion and convulsions with mild gastroenteritis. Lidocaine should be initiated with a bolus of 2mg/kg. If SE is arrested by the bolus, continuous maintenance infusion should follow; treatment should proceed to different measures when SE shows a poor response to the initial bolus of lidocaine.

Kainic acid dose affects delayed cell death mechanism after status epilepticus.

Kainic acid (KA)-induced status epilepticus (SE) produces hippocampal neuronal death, which varies from necrosis to apoptosis or programmed cell death (PCD). We examined whether the type of neuronal death was dependent on KA dose. Adult rats were induced SE by intraperitoneal injection of KA at 9 mg/kg (K9) or 12 mg/kg (K12). Hippocampal neuronal death was assessed by TUNEL staining, electron microscopy, and Western blotting of caspase-3 on days 1, 3 and 7 after SE induction. K12 rats showed higher a mortality rate and shorter latency to the onset of SE when compared with K9 rats. In both groups, acidophilic and pyknotic neurons were evident in CA1 at 24h after SE and neuronal loss developed from day 3. The degenerated neurons became TUNEL-positive on days 3 and 7 in K9 rats but not in K12 rats. Caspase-3 activation was detected on days 3 and 7 in K9 rats but was undetectable in K12 rats. Ultrastructural study revealed shrunken neurons exhibiting pyknotic nuclei containing small and dispersed chromatin clumps 24h after SE in CA1. No cells exhibited apoptosis. On days 3 and 7, the degenerated neurons were necrotic with high electron density and small chromatin clumps. There were no ultrastructural differences between the K9 and K12 groups. These results revealed that differences in KA dose affected the delayed cell death (3 and 7 days after SE); however, no effect was seen on the early cell death (24h after SE). Moderate-dose KA induced necrosis, while low-dose KA induced PCD.

[A child with non-herpetic acute limbic encephalitis affecting the claustrum and hippocampus].

We experienced an 8-year-old-boy with non-herpetic acute limbic encephalitis (NHALE), who developed headache, convulsion, consciousness disturbance, and ataxia following cold like symptoms. Disturbance of short term memory and a change of character were recognized. Myoclonic seizures and generalized tonic clonic convulsions developed, that responded to antiepileptic agents. Although other symptoms resolved spontaneously, short term memory disturbance persisted. Brain MRI demonstrated the lesion involving the bilateral claustrum and right hippocampus. Three months later, the lesion in the claustrum disappeared, but the hippocampus still showed slight hyperintensity on FLAIR image of MRI. Autoantibodies against glutamine receptor were detected in the cerebrospinal fluid and plasma, which suggested the involvement of immunologic disturbances in this disease. In NHALE, many cases have been reported in adults but not in children, and the further attentions should be paid to childhood-onset NHALE.

An infant with idiopathic orbital myositis poorly responsive to steroid therapy: a case report.

A 9-month-old girl developed subacute limited adduction of the left eye, presenting with blepharoptosis. An orbital magnetic resonance imaging (MRI) 2 months after the onset revealed swelling of the left lateral rectus muscle, with increased intensity on T2-weighted images with fat saturation, which was enhanced with gadolinium. She was diagnosed with idiopathic orbital myositis based on history, physical examination, and MRI findings. Swelling of the left lateral rectus muscle was partially reduced by pulse steroid therapy. This is the first reported case of an infant orbital pseudotumor with clinical and MRI findings consistent with subacute orbital myositis. We propose that a fibrotic change of the orbital muscle may occur during a subacute course and would be incompletely responsive to steroid therapy.

Detecting functional asymmetries through the dipole moment of magnetoencephalography.

To assess the accuracy of magnetoencephalography (MEG) as a tool for quantitative detection of neuronal activity, the dipole moment was estimated at N20m of somatosensory evoked fields (SEFs) produced by median nerve stimulation. Neurologically stable patients were examined twice within 2 weeks. Since the estimated moment values of the two examinations should be essentially the same, we assessed the margin of error for our measurement system. The results showed that a change of more than 5.2 nAm is statistically significant (p=0.05; n=91). The patients were classified as without or with functional asymmetries by measuring the conventional cerebral blood flow (CBF) with single photon emission CT (SPECT), and the dipole moment difference between hemispheres was measured. Hemispheric moment differences were statistically larger for the group with CBF laterality, indicating consistency between conventional CBF results and the moment measurements as a group. Moreover, MEG was able to detect more functional asymmetries than CBF study. The dipole moment provided a reliable quantitative index of cortical response to somatosensory stimulus, and the moment measurement thus holds promise as a clinical tool for direct quantification of cortical response.

Usefulness of somatosensory evoked magnetic field dipole measurements by magnetoencephalography for assessing spinal cord function.

OBJECT: Objective assessment of sensory function disorders is difficult. In the present study, the authors investigated the possibility of assessing cervical myelopathy-induced sensory disorders by using magnetoencephalography (MEG) to measure somatosensory evoked magnetic fields (SSEMFs). METHODS: In 12 patients with cervical myelopathy, SSEMFs were measured before and after surgery by using a 160-channel helmet-type MEG system to stimulate the median nerve, and the intensity and latency of N20m (first response occurring 20 msec after stimulation) were then determined. Additionally, the severity of the sensory disorder was assessed before and after surgery by obtaining sensory scores determined using the Neurosurgical Cervical Spine Scale. Furthermore, in 11 healthy individuals (control group), the intensity and latency of N20m were measured in the same fashion. Analysis of the results showed that the preoperative intensity of N20m in the 12 patients with cervical myelopathy was significantly lower than that demonstrated in the control patients (p < 0.005, Student t-test). In addition, of six patients in whom sensory scores improved postoperatively, there were significant increases in the intensity of N20m (p < 0.005, paired t-test). Furthermore, there was a significant correlation between sensory scores and dipole intensity (p < 0.001, Spearman correlation coefficient by rank test). CONCLUSIONS: Somatosensory evoked magnetic field measurements determined by MEG are useful in objectively and noninvasively assessing sensory disorders caused by cervical myelopathy.

Magnetic resonance imaging in occipital lobe epilepsy with frequent seizures.

Magnetic resonance imaging and single-photon emission computed tomography provide useful information in the evaluation of the pathophysiology of epileptic foci. Ictal magnetic resonance imaging in a 7-year-old male with occipital lobe epilepsy revealed mild swelling of the left temporo-occipital region, with hyperintensity on T(2)-weighted and fluid attenuated inversion recovery images. This lesion, however, was not detected on diffusion-weighted imaging. An ictal single-photon emission computed tomography study using 99mTc-ECD demonstrated left temporo-occipital hyperperfusion. T(2)-weighted and fluid attenuated inversion recovery images revealed hyperintensity without atrophy 4 months after control of his seizures. The focus in nonconvulsive status epilepticus has been reported as showing hyperintensity on T(2)-weighted, fluid attenuated inversion recovery and diffusion-weighted images. Since hyperintensity on diffusion-weighted imaging reflects cytotoxic intracellular edema due to excitotoxicity, and his ictal diffusion-weighted image exhibited no remarkable change, the lesions in the left temporo-occipital region resulted from vasogenic edema. Cytotoxic edema resulting from excitotoxicity leads to neuronal death, causing cortical atrophy. Thus, diffusion-weighted imaging is a useful tool to predict the prognosis of frequent seizures.

[Multicenter study of occipital lobe epilepsy in childhood: clinical characteristics].

We investigated the clinical characteristics of 54 patients with childhood onset occipital lobe epilepsy (OLE). There were 25 patients of symptomatic OLE (cortical dysplasia, post encephalitis or encephalopathy, brain tumor and so on), and 29 cases of cryptogenic OLE. Eighteen patients had positive visual symptoms such as flash light, bright spots and sparks of light, 23 patients had negative ones such as scotoma, hemianopia and amaurosis and 10 patients had other complicated visual symptoms such as change of the shape or colors. Young children complained of simple visual phenomena. The youngest patient who could explain visual symptom was 3 years old. All 3 patients with visual field defects had cortical dysplasia in occipital lobe. Ictal SPECT study showed wide hyperperfusion areas in the temporo-parieto-occipital lobe in most of patients with abnormal MRI findings. CBZ and VPA were prescribed in most cases, and were effective in 65% and 60% of the patients, respectively. Seizure prognosis was relatively good. Seizures disappeared in 56% of the patients with symptomatic OLE and 79% of those with cryptogenic OLE.

A case of TUBA1A mutation presenting with lissencephaly and Hirschsprung disease.

Gene mutation of tubulin alpha-1A (TUBA1A), a critical component of microtubules of the cytoskeleton, impairs neural migration and causes lissencephaly (LIS). The approximately 45 cases of disease-associated TUBA1A mutations reported to date demonstrate a wide spectrum of phenotypes. Here we describe an 8-year-old girl with lissencephaly, microcephaly, and early-onset epileptic seizures associated with a novel mutation in the TUBA1A gene. The patient developed Hirschsprung disease and the syndrome of inappropriate antidiuretic hormone secretion (SIADH), which had not previously been described in TUBA1A mutation-associated disease. Our case provides new insight into the wide spectrum of disease phenotypes associated with TUBA1A mutation.

Humoral immune responses against norovirus infections of children.

In 2 infants with gastroenteritis associated with Norovirus (NoV), serum immunoglobulin (Ig) G, IgM, IgA, and fecal IgA antibody responses against NoV were examined by enzyme-linked immunosorbent assay using 11 different antigenic and genetic types of NoV virus-like particles expressed in insect cells. These two cases were putative primary single NoV infections, because antibodies against NoVs were not detected in acute-phase serums. In one of two cases, long-term excretion of virus RNA for 33 days was observed. Serum IgG responses demonstrated strong seroresponse to the homologous type, and weak seroresponse to the heterologous types within the genogroup. After more than 2 years, the IgG antibody titer remained high to the homologous type and low to the heterologous type within the genogroup. IgM and IgA were specific to the homologous type. IgM was short lived and the serum IgA antibody titer remained low to the homologous type for a long period. These results improve our understanding of the humoral immune response to NoV infection.

Time course changes of estrogen receptor alpha expression in the adult rat hippocampus after kainic acid-induced status epilepticus.

Although estrogens possess neuroprotective and epileptogenic properties, the expression pattern of the estrogen receptor (ER) following status epilepticus (SE) remains unclear. We therefore examined the expression pattern of ER alpha in the adult rat hippocampus after SE. SE was induced in rats by kainic acid (KA; 12 mg/kg, i.p.). ER alpha expression was assessed by immunostaining and Western blotting at various times (24 h, and 7, 14, and 21 days) after SE onset. Immunohistochemistry disclosed ER alpha expression in the CA1 and CA3 pyramidal cells of control rats, whereas, after SE, ER alpha-immunoreactive neurons decreased in number due to neuronal death in the CA1 from days 7 to 21. On the other hand, ER alpha-immunoreactive cells with astrocytic morphology were observed in the CA1 beginning on day 7 after SE. This immunoreactivity increased in proportion to the hypertrophy of astrocytes up to day 21. Western blotting revealed a significant decrease in ER alpha expression on day 7 after SE in comparison with control level. However, ER alpha expression on days 14 and 21 were similar when comparing KA-treated and control rats. These results indicate that reactive astrocytes are important sites of estrogen action in the hippocampal CA1 after SE.

Interictal patterns of cerebral glucose metabolism, perfusion, and magnetic field in mesial temporal lobe epilepsy.

PURPOSE: To characterize the epileptogenic condition of patients with mesial temporal lobe epilepsy, the interictal patterns of glucose metabolism, perfusion, and magnetic field in the temporal lobe were evaluated by using [18F]fluorodeoxyglucose-positron emission tomography, [99mTc]-ethylcysteinate dimer-single photon emission computed tomography, and magnetoencephalography (MEG). METHODS: Twenty-one patients with mesial temporal lobe epilepsy related to hippocampal sclerosis were studied. The ictal-onset area was located by continuous video-EEG monitoring. Quantitative analysis of glucose metabolism and perfusion in the temporal lobe was performed, and the cerebral magnetic field was evaluated to measure the equivalent current dipole (MEG-ECD). RESULTS: Although hypometabolism and hypoperfusion in the temporal lobe were lateralized with the ictal-onset area in 16 (76.2%) and in 11 (52.4%) respectively, they were localized in diverse ways without any coupling. MEG-ECD was distributed in diverse ways unrelated to the ictal-onset area: ipsilateral medial temporal origin in five (23.8%), ipsilateral lateral temporal origin in two (9.5%), ipsilateral mixed (medial and lateral) temporal origin in six (28.6%), bilateral temporal origin in four (19.0%), and contralateral temporal origin in two (9.5%). CONCLUSIONS: MEG-ECD was distributed in varied ways with the disorder and uncoupling of glucose metabolism and perfusion in the temporal lobe. These results may help resolve the clinical controversy over the possibility that the cortical irritative area generating the interictal epileptic discharge is distinct from the ictal-onset area, and also may have some functional implications in identifying different brain compartments in the generation of metabolic signals.