The Clinical Course and Treatment of a Case of Refractory Systemic Juvenile Myasthenia Gravis Successfully Treated with Thymectomy.

Juvenile myasthenia gravis (JMG) exhibits a more favorable response to glucocorticoids and has a better prognosis than adult myasthenia gravis. However, no established treatment exists for refractory JMG. Although thymectomy has been performed in several patients with refractory systemic JMG, there are few detailed clinical descriptions of patients who underwent thymectomy. Here, we present the case of a 10-year-old boy with refractory systemic JMG who was successfully treated with thymectomy. The patient developed symptoms, including dysphagia, malaise, diurnal ptosis, and weakness in the trunk muscles, and he was diagnosed with generalized JMG. Despite undergoing various treatments, including steroids, tacrolimus, steroid pulse therapy, intravenous immunoglobulin, azathioprine (AZT), and rituximab, his symptoms did not improve. Therefore, he underwent a thoracoscopic thymectomy 24 months after disease onset. Thymectomy led to remission, as demonstrated by a significant reduction in the quantitative myasthenia gravis score and anti-acetylcholine receptor antibody levels, which persisted for 43 months after surgery. Our case demonstrates the effectiveness of thymectomy in systemic JMG patients with positive anti-acetylcholine receptor antibodies, despite therapeutic failure with AZT and rituximab, within 2 years of disease onset.

Multiple Cerebral Hemorrhages and White Matter Lesions Developing after Severe hMPV Pneumonia in a Patient with Trisomy 13: A Case Report and Review of the Literature.

Human metapneumovirus (hMPV) is a common cause of upper and lower respiratory tract infections in children. A few case reports have described hMPV encephalitis or encephalopathy. Neuroimaging data on patients with hMPV encephalitis are scarce. We report a patient with trisomy 13 who developed severe hMPV pneumonia, multifocal cerebral and cerebellar hemorrhagic infarctions and extensive cerebral white matter demyelination. Although adult respiratory distress syndrome and disseminated intravascular coagulation contributed to the devastating central nervous system (CNS) lesions, endothelial dysfunction of the CNS caused by hMPV infection probably also played a pathophysiological role in this case.

A novel homozygous mutation of the TFG gene in a patient with early onset spastic paraplegia and later onset sensorimotor polyneuropathy.

The tropomyosin-receptor kinase fused gene (TFG) has recently been implicated in several distinct hereditary disorders, including the autosomal-recessive form of complicated hereditary spastic paraplegia called SPG57. Previously, three homozygous variants of the TFG gene were reported in five families with SPG57, in which early onset spastic paraplegia, optic atrophy, and peripheral neuropathy were variably identified. Here, we present the first Japanese patient with SPG57, and have added a homozygous p.Ile66Thr variant as the fourth SPG57 genotype.

Leucine-485 deletion variant of BRAF may exhibit the severe end of the clinical spectrum of CFC syndrome.

The genotype-phenotype correlation in BRAF variant in cardio-facio-cutaneous (CFC) syndrome is not clearly defined. Here we report a case with a severe clinical phenotype and a novel BRAF variant, p.Leu485del. The present case showed severe intellectual disability, impaired awareness, hyperekplexia, involuntary movements, early onset refractory seizures, and delayed myelination on brain magnetic resonance imaging as well as a polycystic and dysplastic kidney, which are previously unreported anomalies in CFC or RAS/mitogen-activated protein kinase syndromes related to BRAF variant. CFC syndrome, especially caused by BRAF variant, should be included in the differential diagnosis of patients with developmental and epileptic encephalopathies and hyperekplexia. Furthermore, we need to keep in mind that missense variants or the deletion of Leucine-485 may be associated with severe symptoms.

High-risk screening for Gaucher disease in patients with neurological symptoms.

Gaucher disease (GD) is an autosomal recessive lysosomal storage disorder caused by the deficiency of glucocerebrosidase enzyme activity. Clinical phenotypes of GD are categorized into three groups: (i) non-neuronopathic GD (type 1), (ii) acute neuronopathic GD (type 2) and (iii) subacute neuronopathic GD (type 3). The high-risk screening of neuronopathic GD has been performed using an enzymatic assay on the dried blood spot (DBS) samples. We enrolled a total of 102 individuals (47 females, 55 males; 0-57 years old; median age 10.5 years) with various neurological symptoms. We detected two patients with very low enzyme activity and they were diagnosed with the disease by using glucocerebrosidase gene analysis. Patient 1 was found to be compound heterozygous for the p.R159W/p.R170C locus and patient 2 was found to harbor two mutations at the IVS7+1G>T (c.999+1G>T) and p.L483P sites. This simple screening protocol using DBS samples is useful for early diagnosis of GD in high-risk and underdiagnosed patients suffering from various neurological symptoms.

A case of new PCDH12 gene variants presented as dyskinetic cerebral palsy with epilepsy.

Here we report a Japanese patient with new compound heterozygous truncating variants in the PCDH12 gene. As compared to the previously reported families who had congenital microcephaly, intrauterine growth retardation, intracranial calcification, and neonatal seizure associated with dysplasia of the midbrain-hypothalamus-optic tract, the present patient showed no midbrain-hypothalamus dysplasia or congenital/postnatal microcephaly, but dyskinetic cerebral palsy and severe intellectual disability as well as multifocal epilepsy. To understand phenotypic spectrum associated with PCDH12 variants, more reports are needed.

A first case of childhood chronic inflammatory demyelinating polyneuropathy associated with alopecia universalis.

Chronic inflammatory demyelinating polyneuropathy (CIDP) is an acquired demyelinating disease of the peripheral nervous system with unknown etiology. Alopecia universalis, an advanced form of alopecia areata (AA), is a condition characterized by complete hair loss. Here we report the first case of childhood CIDP associated with AA who was successfully treated with a combination of intravenous immunoglobulin (IVIg) and corticosteroids. CASE REPORT: This case describes a nine-year-old Japanese girl who developed alopecia, progressive muscle weakness, and eventually loss of walking ability (at ages 2, 4, and 7, respectively). She was treated with IVIg and prednisolone combination therapy, which improved muscle weakness and alopecia. She was positive for serum IgG-GM2 type anti-glycolipid antibodies, which may be associated with this rare combination of diseases.

Reduced efficacy of perampanel in patients with severe motor and intellectual disabilities syndrome and drug-resistant epilepsy: A single-center analysis from Japan.

People with severe motor and intellectual disabilities syndrome (SMIDS) have multiple comorbidities and high mortality rates. This study examined whether there is a difference in the efficacy and tolerability of perampanel (PER) between patients with drug-resistant epilepsy with or without SMIDS. The study identified 65 patients with drug-resistant epilepsy who underwent PER treatment as adjunctive therapy. The 50 % responder rate was 22 % (14/65) overall and 11 % (5/44) in patients with SMIDS versus 43 % (9/21) in patients without SMIDS (p <0.01). Although the overall 50 % responder rate was similar to those of previous reports, PER was less efficacious in the patients with SMIDS; nevertheless, PER was tolerated in the patients with SMIDS.

Two cases of persistent falcine and occipital sinuses.

BACKGROUND: The coexistence of falcine and occipital sinuses is rare and its natural course has not been reported. CASE REPORTS: Two patients with persistent falcine and occipital sinuses are described. Both patients had straight sinuses. In one, both the transverse and sigmoid sinuses were hypoplastic and the patient had an acquired Chiari I malformation. The other patient had no other venous anomalies and had a normal posterior cranial fossa. CONCLUSION: The coexistence of falcine and occipital sinuses can lead to an acquired Chiari I malformation. These cases suggest the importance of checking other venous and brain anomalies in this situation.

Fifteen-year follow-up of a patient with a DHDDS variant with non-progressive early onset myoclonic tremor and rare generalized epilepsy.

BACKGROUND: Generalized epilepsy and tremor phenotypes have been reported in some genetic disorders. Among them benign adult familial myoclonus epilepsy (BAFME) has been confirmed as a clearly defined clinical and genetic entity. On the other hand, non-progressive tremor and generalized epilepsy phenotypes have also been reported in patients with DHDDS variants. CASE PRESENTATION: We report on a long term follow-up of patient with de novo missense variant of DHDDS, who revealed non progressive nature. This 18-year-old woman presented non-progressive tremor since her early infancy. She had rare seizures. Her tremor was considered as cortical myoclonic tremor with giant somatosensory evoked potentials. CONCLUSION: In patients with early onset, non-progressive tremor and rare generalized epilepsy phenotypes, DHDDS variants may be considered in the genetic differential diagnosis.

Two males with sick sinus syndrome in a family with 0.6 kb deletions involving major domains in MECP2.

Mutations in methyl-CpG-binding protein 2 (MECP2) in males can lead to various phenotypes, ranging from neonatal encephalopathy to intellectual disability. In this study, using Nord's method of next-generation sequencing in three siblings, we identified a 0.6 kb deletion involving the transcriptional repression domain (TRD). Two males and one female had intellectual disability and apnea, but none met the criteria of Rett syndrome. Both males had sick sinus syndrome and severe tracheomalacia that resulted in early death. The mother, with skewed X-inactivation, had no symptoms. Therefore, this mutation is pathological for both males and females, resulting in sick sinus syndrome and severe tracheomalacia with strong reproducibility in males. Deletions involving major domains in MECP2 can result in a severe phenotype, and deletion of the TRD domain can cause severe autonomic nervous system dysregulation in males in these cases.

Phenotype-genotype correlations in patients with GNB1 gene variants, including the first three reported Japanese patients to exhibit spastic diplegia, dyskinetic quadriplegia, and infantile spasms.

We report the first three Japanese patients with missense variants in the GNB1 gene. Patients exhibited severe dyskinetic quadriplegia with cortical blindness and epileptic spasms, West syndrome (but with good outcomes), and hypotonic quadriplegia that later developed into spastic diplegia. Whole-exome sequencing revealed two recurrent GNB1 variants (p.Leu95Pro and p.Ile80Thr) and one novel variant (p.Ser74Leu). A recent investigation revealed large numbers of patients with GNB1 variants. Functional studies of such variants and genotype-phenotype correlation are required to enable future precision medicine.

A severe female case of arthrogryposis multiplex congenita with brain atrophy, spastic quadriplegia and intellectual disability caused by ZC4H2 mutation.

Arthrogryposis multiplex congenita (AMC) is characterized by heterogeneous multiple congenital contractures appearing at birth. Mutations in X-linked zinc-finger gene ZC4H2 were recently identified in some families and individuals with variable forms of AMC associated with dysmorphic signs, intellectual disability and spastic paresis. We present a non-consanguineous Japanese female presenting AMC with severe intellectual disability and spastic quadriplegia who also had progressive brain atrophy. Microarray-based comparative genomic hybridization identified 395 kb microdeletions at Xq11.2 which only included ZC4H2 gene. Previous reports showed that affected females have lesser symptoms and slight abnormality on brain MRI compared to male due to X-inactivation. Our case, however, showed severe manifestation than as ever reported as well as progressive diffuse brain atrophy, which implicated contribution of other genetic or environmental factors or extremely skewed X inactivation.

Two Japanese cases of epileptic encephalopathy associated with an FGF12 mutation.

A heterozygous mutation in the fibroblast growth factor 12 (FGF12) gene, which elevates the voltage dependence of neuronal sodium channel fast inactivation, was recently identified in some patients with epileptic encephalopathy. Here we report 1 Japanese patient diagnosed with early infantile epileptic encephalopathy (EIEE) and another diagnosed with epilepsy of infancy with migrating focal seizures (EIMFS). These 2 patients had an identical heterozygous missense mutation [c.341G>A:p.(Arg114His)] in FGF12 , which was identified with whole-exome sequencing. This mutation is identical to previously reported mutations in cases with early onset epileptic encephalopathy. One of our cases exhibited EIMFS, and this case responded to phenytoin and high-dose phenobarbital (PB). FGF12-related epileptic encephalopathy may exhibit diverse phenotypes and may respond to sodium channel blockers or high-dose PB.

[18F]fluorodeoxyglucose-positron emission tomography study of genetically confirmed patients with Dravet syndrome.

OBJECTIVE: To understand cerebral brain dysfunction in patients with Dravet syndrome (DS), we conducted a [18F]fluorodeoxyglucose-positron emission tomography (FDG-PET) study in patients with DS whose SCN1A gene variant was confirmed. METHODS: FDG-PET was performed on eight patients with DS. A SCN1A mutation analysis revealed missense variants in four patients and truncation variants in four patients. The patients' ages at the time of the PET study were 2, 2, 2, 3, 6, 13, 20, and 29 years old, respectively. The patients' developmental/intelligence quotient at the time of the PET study were 62, 52, 64, 35, 30, 15, and <25, respectively. The mean standardized uptake value (SUV) was calculated in four segments (frontal, temporal, parietal, and occipital) for the semi-quantitative analysis of 18F-FDG uptake. This value represents the average of the regions of interest in each lobe and was divided by the average SUV of the cerebellar hemisphere of each patient and compared between the patients with DS and the diseased controls. RESULTS: Glucose uptake in patients with DS decreased significantly, particularly in those ≥6 years old. Importantly, a comparison between the younger and older patients with DS revealed that glucose uptake was normal in patients who were ≤3 years (2, 2, 2, and 3 years), whereas a profound reduction in glucose uptake in the fronto-temporo-parietal-occipital cortices was observed in patients ≥ 6 years (6, 13, 20, and 29 years). Magnetic resonance imaging revealed no detectable atrophic legions or other changes in the cerebral cortices of patients ≥ 6 years of age. SIGNIFICANCE: The present study showed a remarkable reduction in cerebral glucose metabolism in multiple lobes for the first time, which became obvious after the late infantile period. These findings may indicate a functional neuroimaging aspect of epileptic encephalopathy of DS or a feature of the SCN1A variant itself.

Genomic analysis identifies masqueraders of full-term cerebral palsy.

OBJECTIVE: Cerebral palsy is a common, heterogeneous neurodevelopmental disorder that causes movement and postural disabilities. Recent studies have suggested genetic diseases can be misdiagnosed as cerebral palsy. We hypothesized that two simple criteria, that is, full-term births and nonspecific brain MRI findings, are keys to extracting masqueraders among cerebral palsy cases due to the following: (1) preterm infants are susceptible to multiple environmental factors and therefore demonstrate an increased risk of cerebral palsy and (2) brain MRI assessment is essential for excluding environmental causes and other particular disorders. METHODS: A total of 107 patients-all full-term births-without specific findings on brain MRI were identified among 897 patients diagnosed with cerebral palsy who were followed at our center. DNA samples were available for 17 of the 107 cases for trio whole-exome sequencing and array comparative genomic hybridization. We prioritized variants in genes known to be relevant in neurodevelopmental diseases and evaluated their pathogenicity according to the American College of Medical Genetics guidelines. RESULTS: Pathogenic/likely pathogenic candidate variants were identified in 9 of 17 cases (52.9%) within eight genes: CTNNB1,CYP2U1,SPAST,GNAO1,CACNA1A,AMPD2,STXBP1, and SCN2A. Five identified variants had previously been reported. No pathogenic copy number variations were identified. The AMPD2 missense variant and the splice-site variants in CTNNB1 and AMPD2 were validated by in vitro functional experiments. INTERPRETATION: The high rate of detecting causative genetic variants (52.9%) suggests that patients diagnosed with cerebral palsy in full-term births without specific MRI findings may include genetic diseases masquerading as cerebral palsy.

A patient with Muenke syndrome manifesting migrating neonatal seizures.

We report a patient with Muenke syndrome who had repetitive apneic spell followed by focal status epilepticus in the early infancy. Ictal EEG showed focal spikes bursts originated from the left hemisphere and sifted to the right hemisphere, during which he had migrating tonic seizures from right side of the body to the left side of the body. Brain MRI showed abnormal development of bilateral hippocampus, which was characterized as abnormal folding of hippocampal gyri. However, the long-term seizure prognosis was favorable. Results from this and previous studies failed to support the notion that FGFR3 (P250) mutation results in epileptic encephalopathy.

Aquaporin-4 autoimmunity in a child without optic neuritis and myelitis.

Neuromyelitis optica (NMO) is an inflammatory demyelinating disease with a poor prognosis that is characterized by inflammatory optic neuritis and myelitis. Although it is commonly misdiagnosed as multiple sclerosis (MS), distinguishing NMO from MS is important, as therapeutic approaches approved for MS are ineffective in patients with NMO. The aquaporin-4 (AQP4) antibody is a pathogenic and diagnostic biomarker for NMO. We report an AQP4 antibody-positive 9-year-old female with intractable hiccups and nausea (IHN). Brain imaging revealed lesions in the brainstem, thalami, and hypothalamus. Nevertheless, she had no clinical or radiological signs referable to the optic nerve or spinal cord. We propose that in patients with characteristic IHN associated lesions involving the brainstem or hypothalamus, measurement of AQP4 antibody should be considered for selectivity of treatment, even if the patient has no optic nerve or spinal cord lesions.