Interstitial microdeletions of 3q26.2q26.31 in two patients with neurodevelopmental delay and distinctive features.

Interstitial microdeletions in the long arm of chromosome 3 are rare. In this study, we identified two patients with approximately 5-Mb overlapping deletions in the 3q26.2q26.31 region. Both patients showed neurodevelopmental delays, congenital heart defects, and distinctive facial features. One of them showed growth deficiency and brain abnormalities, as shown on a magnetic resonance imaging scan. Haploinsufficiency of NLGN1 and FNDC3B present in the common deletion region was considered to be responsible for neurodevelopmental delay and the distinctive features, respectively. The possibility of unmasked variants in PLD1 was considered and analyzed, but no possible pathogenic variant was found, and the mechanism of the congenital heart defects observed in the patients is unknown. Because 3q26.2q26.31 deletions are rare, more information is required to establish genotype-phenotype correlations associated with microdeletions in this region.

Behavioral problems and family distress in tuberous sclerosis complex.

BACKGROUND: Tuberous sclerosis complex (TSC)-associated neuropsychiatric disorders (TAND) have a large impact on patients and their families. Improving intellectual ability outcomes using preventive vigabatrin (VGB) treatment has recently been reported. AIM: The aim of this study was to investigate the severity of behavioral problems and degree of distress among families of patients with TSC with and without a history of VGB treatment. METHOD: The study enrolled 21 children and adolescents who were patients with TSC from four hospitals: 14 in the VGB group and 7 in the no-VGB group. To evaluate patients' psychiatric and neurological symptoms, we used the TAND Checklist, Aberrant Behavior Checklist (ABC), Social Communication Questionnaire (SCQ), and Social Responsive Scale-2nd edition (SRS-2). RESULTS: All VGB-group patients were administered VGB after the onset of epileptic seizures. No obvious differences were observed between the VGB and no-VGB groups in behavioral problem scores on the TAND Checklist, or on the ABC, SCQ, and SRS-2 total scores. Behavioral problem scores were lower in patients with normal intelligence than in those with mild intellectual disability (ID; P = 0.042). Degrees of family distress assessed with the TAND Checklist were not correlated with the intelligence quotient/developmental quotient (IQ/DQ) or seizure frequency but were correlated with the total SRS-2 scores (P = 0.022). For several patients, there were large discrepancies between familial and physician ratings of the TAND impact score. CONCLUSION: Children and adolescents with TSC may present with significant behavioral difficulties and family distress, regardless of whether they were treated with VGB or not after the onset of seizures. Difficulties in social communication may have the strongest "TAND impact" on families.

De Novo mutations in GNAO1, encoding a Gαo subunit of heterotrimeric G proteins, cause epileptic encephalopathy.

Heterotrimeric G proteins, composed of α, ß, and γ subunits, can transduce a variety of signals from seven-transmembrane-type receptors to intracellular effectors. By whole-exome sequencing and subsequent mutation screening, we identified de novo heterozygous mutations in GNAO1, which encodes a Gαo subunit of heterotrimeric G proteins, in four individuals with epileptic encephalopathy. Two of the affected individuals also showed involuntary movements. Somatic mosaicism (approximately 35% to 50% of cells, distributed across multiple cell types, harbored the mutation) was shown in one individual. By mapping the mutation onto three-dimensional models of the Gα subunit in three different complexed states, we found that the three mutants (c.521A>G [p.Asp174Gly], c.836T>A [p.Ile279Asn], and c.572_592del [p.Thr191_Phe197del]) are predicted to destabilize the Gα subunit fold. A fourth mutant (c.607G>A), in which the Gly203 residue located within the highly conserved switch II region is substituted to Arg, is predicted to impair GTP binding and/or activation of downstream effectors, although the p.Gly203Arg substitution might not interfere with Gα binding to G-protein-coupled receptors. Transient-expression experiments suggested that localization to the plasma membrane was variably impaired in the three putatively destabilized mutants. Electrophysiological analysis showed that Gαo-mediated inhibition of calcium currents by norepinephrine tended to be lower in three of the four Gαo mutants. These data suggest that aberrant Gαo signaling can cause multiple neurodevelopmental phenotypes, including epileptic encephalopathy and involuntary movements.

De novo KCNT1 mutations in early-onset epileptic encephalopathy.

KCNT1 mutations have been found in epilepsy of infancy with migrating focal seizures (EIMFS; also known as migrating partial seizures in infancy), autosomal dominant nocturnal frontal lobe epilepsy, and other types of early onset epileptic encephalopathies (EOEEs). We performed KCNT1-targeted next-generation sequencing (207 samples) and/or whole-exome sequencing (229 samples) in a total of 362 patients with Ohtahara syndrome, West syndrome, EIMFS, or unclassified EOEEs. We identified nine heterozygous KCNT1 mutations in 11 patients: nine of 18 EIMFS cases (50%) in whom migrating foci were observed, one of 180 West syndrome cases (0.56%), and one of 66 unclassified EOEE cases (1.52%). KCNT1 mutations occurred de novo in 10 patients, and one was transmitted from the patient's mother who carried a somatic mosaic mutation. The mutations accumulated in transmembrane segment 5 (2/9, 22.2%) and regulators of K(+) conductance domains (7/9, 77.8%). Five of nine mutations were recurrent. Onset ages ranged from the neonatal period (<1 month) in five patients (5/11, 45.5%) to 1-4 months in six patients (6/11, 54.5%). A generalized attenuation of background activity on electroencephalography was seen in six patients (6/11, 54.5%). Our study demonstrates that the phenotypic spectrum of de novo KCNT1 mutations is largely restricted to EIMFS.

[Evaluation of surgical treatment for intractable aspiration in neurologically impaired patients: our experience with 20 patients].

OBJECTIVE: The present study aimed to evaluate the efficacy of surgical treatment for intractable aspiration in patients with severe motor and intellectual disabilities (SMID) and neuromuscular diseases (NMD). METHODS: A retrospective analysis was performed of 20 patients who underwent laryngotracheal separation (LTS) or the tracheal flap method (TFM) between 2003 and 2012 at Gunma Children's Medical Center. RESULTS: All patients were bedridden and fed either through a naso-gastric or naso-esophageal tube or via a gastric fistula. Of the 20 participants, 60% underwent surgical treatment before 3 years of age. The incidence of aspiration pneumonia decreased after surgery, and 8 of 10 patients, who were previously hospitalized for a long duration, were discharged. The most frequent complications observed were granulation around the tracheostomy stoma and endotracheal granuloma. Two patients presented with a tracheal fistula. CONCLUSION: LTS and TFM can be used as treatment modalities for patients with intractable aspiration along with SMID and NMD. In patients with intractable aspiration, after considering their underlying conditions, adaptation and type of operative procedures should be determined.

Severe pediatric acute encephalopathy syndromes related to SARS-CoV-2.

Background and objectives: To clarify whether severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection cause acute encephalopathy in children and which are the most common syndromes that cause them and what are the outcomes. Methods: A nationwide web-based survey among all members of the Japanese Society of Child Neurology to identify pediatric patients aged < 18 years who developed acute encephalopathy in Japan between 1 January 2020 and 31 May 2022 associated with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection confirmed by polymerase chain reaction or antigen tests using pharyngeal swabs. Acute encephalopathy was defined as acute onset of impaired consciousness lasting > 24 h or an altered mental state; neurological symptoms arising within 2 weeks of onset of COVID-19 or multisystem inflammatory syndrome in children (MIS-C)/pediatric inflammatory multisystem syndrome (PIMS); evidence of SARS-CoV-2 infection; and reasonable exclusion of other diseases. Patients were divided into the known clinico-radiological acute encephalopathy syndrome group and unexplained or unclassifiable acute encephalopathy group. Outcomes were assessed by pediatric cerebral performance category (PCPC) score at hospital discharge. Results: Of the 3,802 society members, 217 representing institutions responded, and 39 patients with suspected acute encephalopathy were reported, of which 31 met inclusion criteria. Of these patients, 14 were diagnosed with known clinico-radiological acute encephalopathy syndromes, with acute encephalopathy with biphasic seizures and late reduced diffusion (five patients) being the most common. Five developed acute encephalopathy associated with MIS-C/PIMS. Among 31 patients, 9 (29.0%) had severe sequelae or died (PCPC ≥ 4). Two of three patients with encephalopathy with acute fulminant cerebral edema and two with hemorrhagic shock and encephalopathy syndrome died. The PCPC scores were higher in the known clinico-radiological acute encephalopathy syndrome group than in the unexplained or unclassifiable acute encephalopathy group (P < 0.01). Discussion: Acute encephalopathy related to SARS-CoV-2 infection was demonstrated to be more severe than that caused by other viruses in Japan. Acute encephalopathy syndromes characterized by specific neuroradiological findings was associated with poor clinical outcomes.

Respiratory syncytial virus-associated encephalopathy complicated by congenital myopathy.

A 23-month-old Japanese girl with a severe form of congenital fiber type disproportion myopathy under mechanical ventilation suffered from respiratory syncytial virus (RSV) bronchiolitis, complicated with acute encephalopathy. She showed consciousness disturbance and convulsions followed by severe brain damage, a rare complication in RSV infection. Patients with severe neuromuscular diseases are vulnerable to RSV infection. Prophylactic interventions should be recommended.

Serum and cerebrospinal fluid S100B, neuron-specific enolase, and total tau protein in acute encephalopathy with biphasic seizures and late reduced diffusion: a diagnostic validity.

BACKGROUND: Acute encephalopathy with biphasic seizures and late reduced diffusion (AESD) is characterized clinically by biphasic seizures and late magnetic resonance imaging abnormalities, such as reduced subcortical diffusion from day 3 onwards, often accompanied with some neurological sequelae. In the early stages of the disease, AESD closely resembles its far more prevalent and relatively benign counterpart, febrile seizure (FS). METHODS: We measured and compared the serum or cerebrospinal fluid (CSF) levels of S100B, neuron-specific enolase (NSE), and total tau protein in 43 patients with FS and 18 patients with AESD, at any point during the disease. To assess early diagnostic validity, we compared these biomarkers in 43 FS and eight AESD patients, with whom the day 0-2 samples were available. We used the receiver-operator characteristic curve to evaluate the diagnostic values of these markers. RESULTS: The levels of all biomarkers were significantly higher in AESD than FS patients. When only day 0-2 samples from AESD patients were used, the levels of all the measured biomarkers, except serum NSE, were still significantly higher in patients with AESD than in FS, suggesting that AESD could damage astrocytes, neurons, and axons, even in the early stages of the disease. According to the receiver-operator characteristic curve analyses, CSF S100B (cut-off value, 100 pg/mL) and CSF total tau protein (cut-off value, 100 pg/mL) were better predictors of AESD than other biomarkers. CONCLUSION: The combination of CSF S100B and CSF total tau protein resulted in a positive predictive value of AESD 83.3%, which could be helpful for early diagnosis, facilitating early therapeutic interventions.

Interstitial deletions in the proximal regions of 6q: 12 original cases and a literature review.

Interstitial microdeletions in the proximal region of the long arm of chromosome 6 are rare. Herein we have reported 12 patients with developmental delays associated with interstitial microdeletions in 6q ranging from q12 to q22. The microdeletions were detected by chromosomal microarray testing. To confirm the clinical significance of these deletions, genotype-phenotype correlation analysis was performed using genetic and predicted loss-of-function data. SIM1 was recognized as the gene responsible for developmental delay, particularly in Prader-Willi syndrome-like phenotypes. Other genes possibly related to developmental delay were ZNF292, PHIP, KCNQ5, and NUS1. To further establish the correlation between the genotype and phenotype, more patient information is required.

Acute encephalopathy with biphasic seizures and late reduced diffusion; posterior frontal hyperperfusion before late seizures revealed by arterial spin labeling: A case report.

BACKGROUND: Arterial spin labeling, a magnetic resonance imaging modality that can evaluate cerebral perfusion without using a contrast material or ionizing radiation, is becoming increasingly accessible. However, only a few reports have used this method to assess the perfusion abnormalities observed in acute encephalopathy with biphasic seizures and late reduced diffusion. PATIENT DESCRIPTION: A 10-month-old Japanese girl presented with febrile status epilepticus (early seizures). Her convulsions ceased after the administration of intravenous phenobarbital, although her impaired consciousness was protracted. Five days later, diffusion-weighted imaging revealed slightly high signal intensity lesions in the bilateral posterior frontal areas. Arterial spin labeling revealed bilateral frontal-dominant hypoperfusion and posterior frontal hyperperfusion. On day 6, she had three convulsions (late seizures) and was diagnosed with acute encephalopathy with biphasic seizures and late reduced diffusion. She received treatment accordingly and recovered eventually. DISCUSSION: Based on previous reports, hypoperfusion within 1-2 days of early seizures and hyperperfusion accompanied by bright tree appearance on diffusion-weighted imaging within 1-2 days of late seizures are typical in acute encephalopathy with biphasic seizures and late reduced diffusion. In our patient, the first magnetic resonance imaging scan was performed one day prior to the onset of late seizures. We observed posterior frontal hyperperfusion accompanied by high signals on diffusion-weighted imaging, which leads us to speculate that this could be a predictive marker of late seizures.

Acute encephalopathy in children with tuberous sclerosis complex.

OBJECTIVE: We examined the clinical manifestations of acute encephalopathy (AE) and identify risk factors for AE in children with tuberous sclerosis complex (TSC). METHODS: The clinical data of 11 children with clinically diagnosed TSC associated with AE and 109 children with clinically diagnosed TSC alone aged 4 years or older were collected from 13 hospitals. RESULTS: Of the 11 children with AE, 5 had histories of febrile seizures (FS), and all had histories of febrile status epilepticus (FSE). AE developed within 24 h after fever onset in all children with seizures lasting 30 min or longer. All children developed coma after seizure cessation. Head magnetic resonance imaging (MRI) revealed widespread abnormalities in the cerebral cortex, subcortical white matter, corpus callosum, basal ganglia, and thalamus. One child died; seven had severe neurological sequelae; and the other three, mild sequelae. Logistic regression analysis revealed that a history of FSE was correlated with the development of AE. SIGNIFICANCE: AE in children with TSC was characterized by sudden onset after fever, followed by coma, widespread brain edema evident on MRI, and poor outcomes. A history of FSE was a risk factor for the development of AE.

Various types of LRP5 mutations in four patients with osteoporosis-pseudoglioma syndrome: identification of a 7.2-kb microdeletion using oligonucleotide tiling microarray.

Osteoporosis-pseudoglioma syndrome (OPS; OMIM 259770) is an autosomal-recessive genetic disorder characterized by severe osteoporosis and visual disturbance from childhood. Biallelic mutations in the low-density lipoprotein receptor-related protein 5 gene (LRP5) have been frequently detected, while a subset of patients had only one or no detectable mutation. We report on the clinical and molecular findings of four unrelated Japanese patients with the syndrome. The four patients had typical skeletal and ocular phenotypes of OPS, namely severe juvenile osteoporosis and early-onset visual disturbance, with or without mental retardation. We undertook standard PCR-based sequencing for LRP5 and found four missense mutations (p.L145F, p.T244M, p.P382L, and p.T552M), one nonsense mutation (p.R1534X), and one splice site mutation (c.1584+1G>A) among four OPS patients. Although three patients had two heterozygous mutations, one had only one heterozygous splice site mutation. In this patient, RT-PCR from lymphocytic RNA demonstrated splice error resulting in 63-bp insertion between exons 7 and 8. Furthermore, the patient was found to have only mutated RT-PCR fragment, implying that a seemingly normal allele did not express LRP5 mRNA. We then conducted custom- designed oligonucleotide tiling microarray analyses targeted to a 600-kb genome region harboring LRP5 and discovered a 7.2-kb microdeletion encompassing exons 22 and 23 of LRP5. We found various types of LRP5 mutations, including an exon-level deletion that is undetectable by standard PCR-based mutation screening. Oligonucleotide tiling microarray seems to be a powerful tool in identifying cryptic structural mutations.

A case of pyridoxine-dependent epilepsy with novel ALDH7A1 mutations.

Pyridoxine-dependent epilepsy (PDE) is a rare autosomal-recessive disorder typically presenting with neonatal seizures and is sometimes difficult to diagnose, because the clinical features mimic those of birth asphyxia. A Japanese newborn boy presented with pulmonary haemorrhage and convulsions on the day of birth. Brain computed tomography showed diffuse, but mild, low-density cerebral white matter and a thin subdural hematoma in the posterior fossa. He did not have thrombocytopenia or coagulopathy. His respiratory status improved with conservative treatment, but his convulsions were persistent even after prescription of several antiepileptic drugs. His serum and cerebrospinal fluid showed decreased vitamin B6 vitamers and increased upstream metabolites of α-aminoadipic semialdehyde dehydrogenase, strongly suggesting a diagnosis of PDE; the epileptic spasms ceased after administration of intravenous pyridoxal phosphate hydrate. Gene analysis revealed novel compound heterozygous mutations in ALDH7A1 that included NM_001182.4:[c.1196G > T] and [c.1200 + 1G > A]. Atypical birth asphyxia with persistent neonatal seizure should prompt vitamin B6/metabolite screening.

A patient with early onset Huntington disease and severe cerebellar atrophy.

We report on a girl with early onset Huntington disease (HD). Her initial symptoms at 2 years of age included oral motor dysfunction and gait disturbance. Magnetic resonance imaging of the head revealed severe atrophy of both the vermis and the cerebellar cortex in addition to the common findings of basal ganglia including the caudate nuclei, putamen, and globus pallidus. Molecular analysis showed 160 CAG repeats in the HD gene. This mutation was inherited from her mother who was also affected, with a HD CAG expansion of 60 repeats. Cerebellar symptoms should be considered as a manifestation of early onset HD.

Sweet Potato Was Not So Sweet: Undetected Foreign-body Aspiration in a Healthy Child Leading to Acute Bronchial Asthma.

INTRODUCTION: Sweet potato may contain furanoterpenoids, including ipomeamarone, which cause lung edema. CASE PRESENTATION: A 10-year-old schoolgirl was hospitalized with asthma exacerbation and acute pneumonia. Chest radiographs showed a diffuse opacity of the left lung and hyperpermeability of the right lung. Computed tomography indicated foreign-body aspiration. Flexible bronchoscopy revealed an inhaled piece of sweet potato obstructing the left main bronchus. Although the patient's dyspnea worsened after removal of the sweet potato, she recovered with the treatment based on the 2014 Japanese Childhood Asthma Guidelines. CONCLUSION: Cases of sweet potato aspiration need careful treatment after removal of the foreign body.

Rhinovirus-associated acute encephalitis/encephalopathy and cerebellitis.

BACKGROUND: Rhinovirus is a common respiratory pathogen for children throughout the year; nevertheless, its central nervous system involvement is extremely rare, and only two cases have been reported to date: meningitis and sepsis-like illness. PATIENT: A previously healthy 2-year-old Japanese boy developed fever, followed by seizures and lethargy. His cerebrospinal fluid cell count and protein level were slightly increased; brain magnetic resonance imaging showed abnormal intensities in the bilateral cerebellar dentate nuclei, which were prominent in diffusion-weighted images. After his consciousness disturbance improved, cerebellar dysfunction became apparent. He was treated symptomatically, without steroids or any other immunosuppressants. He almost recovered within a few months; however, cerebellar atrophy became evident on brain magnetic resonance imaging. Using acute specimens, human rhinovirus A was detected in his throat swab and cerebrospinal fluid. DISCUSSION: Acute cerebellitis, in which cerebellar inflammation is predominant, is occasionally accompanied by cerebral symptoms, such as consciousness disturbance and seizures. As a causative pathogen, rotavirus is the most common; however, rhinovirus-associated acute encephalitis/encephalopathy and concurrent cerebellitis have not been reported before. Further research, using recent molecular techniques to detect various central nervous system pathogens, including rhinovirus, is needed to delineate the underlying pathophysiology.

Thermolabile polymorphism of carnitine palmitoyltransferase 2: A genetic risk factor of overall acute encephalopathy.

OBJECTIVES: Acute encephalopathy is an acute brain dysfunction after preceding infection, consisting of multiple syndromes. Some syndromes, such as acute encephalopathy with biphasic seizures and late reduced diffusion (AESD), are severe with poor outcome, whereas others, such as clinically mild encephalitis/encephalopathy with reversible splenial lesion (MERS), are mild with favorable outcome. Previous study reported the association of the thermolabile polymorphism in Carnitine Palmitoyltransferase 2 (CPT2) gene and severe syndromes of acute encephalopathy. To further explore the pathogenetic role of CPT2 in acute encephalopathy, we conducted a case-control association study of a typical thermolabile CPT2 polymorphism, rs2229291, in 416 patients of acute encephalopathy, including both severe and mild syndromes. METHODS: The case cohort consisted of 416 patients, including AESD, MERS, and other syndromes. The control subjects were 100 healthy Japanese. rs2229291 was genotyped by Sanger sequencing. Genetic distribution was compared between the patients and controls using Cochran-Armitage trend test. RESULTS: Minor allele frequency of rs2229291 was significantly higher in AESD (p = 0.044), MERS (p = 0.015) and entire acute encephalopathy (p = 0.044) compared to the controls. The polymorphism showed no significant association with influenza virus, or with outcome. CONCLUSIONS: This study provided evidence that CPT2 is a susceptibility gene for overall acute encephalopathy, including both severe and mild syndromes, and suggested that impairment of mitochondrial metabolism is common to various syndromes of acute encephalopathy.

De novo variants in CAMK2A and CAMK2B cause neurodevelopmental disorders.

Objective: α (CAMK2A) and ß (CAMK2B) isoforms of Calcium/calmodulin-dependent protein kinase II (CaMKII) play a pivotal role in neuronal plasticity and in learning and memory processes in the brain. Here, we explore the possible involvement of α- and ß-CaMKII variants in neurodevelopmental disorders. Methods: Whole-exome sequencing was performed for 976 individuals with intellectual disability, developmental delay, and epilepsy. The effect of CAMK2A and CAMK2B variants on CaMKII structure and firing of neurons was evaluated by computational structural analysis, immunoblotting, and electrophysiological analysis. Results: We identified a total of five de novo CAMK2A and CAMK2B variants in three and two individuals, respectively. Seizures were common to three individuals with CAMK2A variants. Using a minigene splicing assay, we demonstrated that a splice site variant caused skipping of exon 11 leading to an in-frame deletion of the regulatory segment of CaMKII α. By structural analysis, four missense variants are predicted to impair the interaction between the kinase domain and the regulatory segment responsible for the autoinhibition of its kinase activity. The Thr286/Thr287 phosphorylation as a result of release from autoinhibition was increased in three mutants when the mutants were stably expressed in Neuro-2a neuroblastoma cells. Expression of a CaMKII α mutant in primary hippocampal neurons significantly increased A-type K+ currents, which facilitated spike repolarization of single action potentials. Interpretation: Our data highlight the importance of CaMKII α and CaMKII ß and their autoinhibitory regulation in human brain function, and suggest the enhancement of A-type K+ currents as a possible pathophysiological basis.

Acute cerebellar ataxia and consecutive cerebellitis produced by glutamate receptor delta2 autoantibody.

Acute cerebellar ataxia is usually a self-limited benign disease, which may develop in children after certain viral infections or vaccinations. There are several reports of acute cerebellar ataxia associated with autoantibodies. Glutamate receptor delta2, a member of the glutamate receptor family, is predominantly expressed in cerebellar Purkinje cells and plays a crucial role in cerebellar functions. To date anti-GluRdelta2 autoantibody was detected in a patient with chronic cerebellitis. Herein, an 18-month-old boy presented with cerebellar ataxia 9 days following a mild respiratory tract infection. Although cerebellar ataxia gradually improved, it worsened yet again following mumps and varicella virus infection. Cerebro-spinal fluid examination and magnetic resonance imaging of the brain demonstrated pleocytosis and meningeal enhancement, respectively. Furthermore, glutamate receptor delta2 autoantibody was detected in serum and cerebro-spinal fluid. Thus, we believe that the glutamate receptor delta2 autoantibody may play a role in cerebellar ataxia and consecutive cerebellitis.