Compound heterozygous variants of the NARS2 gene in siblings with developmental delay, epilepsy, and neonatal diabetes syndrome.

Neonatal diabetes mellitus (NDM) with developmental delay and epilepsy is classified as developmental delay, epilepsy, and neonatal diabetes (DEND) syndrome. The majority of DEND syndrome are due to severely damaging variants of K-ATP channels, and few mitochondria-related genes have been reported. We report here two Japanese siblings who were clinically diagnosed with DEND syndrome in whom NARS2 compound heterozygous variants were detected. Patient 1 was a 3-year-old girl and presented with diabetes ketoacidosis at 3 months old. Patient 2 was a 1-year-old boy who presented with severe hyperglycemia and started insulin therapy at 3 days old. After the first episodes, they both presented with severe developmental delay, hearing loss and treatment-resistant epilepsy accompanied by progressive brain atrophy. Whole-exome sequencing revealed compound heterozygous NARS2 p.R159C and p.L217V variants, and the GATA4 p.P407Q variant in both patients. They were treated by mitochondrial supportive therapy of vitamin B1, L-carnitine, and coenzyme Q10. Patient 2 was withdrawn from insulin therapy at 6 months old. This is the first report of NDM in which variants of the NARS2 gene coding mitochondrial protein were detected. Genetic analysis including mitochondrial genes should be considered in patients with neonatal onset diabetes associated with neurogenic symptoms.

Clinical profile of reading ability and reading and writing achievement of children with borderline full-scale intellectual quotient: a prospective study.

BACKGROUND: Poor reading ability is one of the common causes of low academic performance. In previous studies, children with dyslexia were found to demonstrate poor academic achievement due to poor reading ability. However, the relationship between academic achievement and reading ability in children with a borderline full-scale intellectual quotient (FSIQ) is unknown. This study aimed to clarify the clinical characteristics of children with borderline FSIQ and poor reading ability, and differentiate these characteristics from those of children with higher FSIQ and poor reading ability. METHODS: A total of 126 children (aged 6-15 years) identified as having low academic performance were enrolled. The reading ability of children was assessed through their performance on the hiragana (Japanese syllabary) reading task, while their reading and writing achievement was assessed through their reading and writing score on the Kaufman Assessment Battery for Children, Second Edition. Children were categorized into two groups based on their FSIQ score (FSIQ > 85 and 85 ≥ FSIQ ≥ 70). Reading ability in children was evaluated by referring to the linear relationship between FSIQ and the standard deviation value of reading tasks in typically developing children. A one-way analysis of variance (ANOVA) was performed to examine clinical characteristics between higher and lower FSIQ groups. Associations between reading and writing achievement, reading ability, and ages of children were assessed using Pearson's product-moment correlation coefficients for the higher and lower FSIQ groups. RESULTS: Poorer reading and writing achievement was associated with poorer reading ability in the higher FSIQ group. Conversely, poorer reading and writing achievement and poor reading ability were associated with older age in the lower FSIQ group. CONCLUSIONS: Poor reading and writing achievement were associated with older age, not with poor reading ability in the lower FSIQ group. Children with lower FSIQ need appropriate educational interventions based on independent assessments to further their academic achievement and reading ability. Moreover, they need more frequent evaluations of their academic achievement than do children with higher FSIQ and poor reading ability since they are more likely to be at a lower academic achievement level at an older age.

Association between lack of functional connectivity of the frontal brain region and poor response inhibition in children with frontal lobe epilepsy.

PURPOSE: We investigated the relationship between electroencephalographic (EEG) functional connectivity and executive function in children with frontal lobe epilepsy (FLE). METHODS: We enrolled 24 children with FLE (mean age, 11.0 years; 13 boys) and 22 sex-, age-, and intelligence-matched typically developing children (TDC) to undergo 19-channel EEG during light sleep. We estimated functional connectivity using the phase lag index (PLI) that captures the synchronization of EEG. We also performed continuous performance tests (CPTs) on the children and obtained questionnaire responses on attention deficit hyperactivity disorder and oppositional defiant disorder (ODD). RESULTS: The average gamma PLI was lower in the FLE group than in the TDC group, especially between long-distance frontoparietal pairs, between interhemispheric frontal pairs, and between interhemispheric parietotemporal pairs. Gamma PLIs with long-distance frontoparietal and interhemispheric frontal pairs were positively associated with inattention, ODD scores, omission error, and reaction time in the FLE group but not in the TDC group. Conversely, they were negatively associated with age, hyperactivity score, and commission error. CONCLUSIONS: A lack of functional connectivity of the frontal brain regions in children with FLE was associated with poor response inhibition.

Adaptive behavior and its related factors in children with focal epilepsy.

OBJECTIVE: We aimed to clarify the strengths and weaknesses in adaptive behavior in children with focal epilepsy and show children-associated factors related to adaptive behavior. MATERIALS AND METHODS: Sixty-three children with focal epilepsy aged 5-18 years with intellectual quotient (IQ) ranging from 67 to 135 were enrolled in this study. Adaptive behavior was evaluated using the Vineland Adaptive Behavior Scale, 2nd edition (VABS-II). The children performed continuous performance test and tests of reading, writing, and IQ; parents answered questionnaires regarding attention-deficit hyperactivity disorder and autism spectrum disorder (ASD). Participants were categorized into four groups based on IQ and adaptive behavior scores for statistical comparisons. RESULTS AND DISCUSSION: Children with low adaptive behavior were more likely to show a reduction in daily living skills, and those with both low adaptive behavior and IQ were more likely to show a reduction in daily living skills and communication. Lower adaptive behavior was related to more severe autistic symptoms, lower academic achievement in children with IQ > 85, and lower executive function in children with IQ ≤ 85. There was a qualitative difference of cognitive dysfunction in adaptive behavior between both groups. CONCLUSIONS: There were differences in VABS-II domain and subdomain characteristics between children with focal epilepsy and those with ASD; however, it was more difficult for children with more severe ASD and coexisting focal epilepsy to show age-equivalent adaptive behavior.

[The efficacy of intravenous alendronate for osteoporosis in patients with severe motor intellectual disabilities].

Objective: Bone fractures in patients with severe motor and intellectual disabilities (SMIDs) have become an important problem to be solved. These fractures may result from disuse osteoporosis. Bisphosphonate administration is generally the most established treatment for patients with osteoporosis. However, traditional oral bisphosphonate use is associated with esophagitis as a side effect and may increase the risk of reflux esophagitis for bedridden patients. Intravenous alendronate, one of the bisphosphonates, was released in 2012 in Japan. Though it is appropriate for patients with SMIDs, there are no reports about the effects of intravenous alendronate on osteoporosis in SMID patients. Therefore, the efficacy of intravenous alendronate for osteoporosis was investigated in SMID patients. Methods: The subjects were 62 SMID patients with osteoporosis (20 to 60 years old) in our hospital. They were divided two groups, bisphosphonate treatment group (32 patients) and age-matched controls (30 patients). Patients in bisphosphonate treatment groups were given 900µg intravenous alendronate once a month. All patients were also administered oral vitamin D3. Serial bone density, bone metabolism markers, and existence of fractures were compared in both groups before and after treatment (6 months, 1 years, and 2 years). Results: In bisphosphonate treatment group, the change rate of bone density was significantly increased and bone metabolism markers were improved at 6 months and 1 year after starting treatment. After a year, 16 patients in treatment group changed into other treatments, and 12 controls started bisphosphonate treatment. In remaining treatment group (16 patients), the change rate of bone density and bone metabolism markers were improved significantly at 2 years after starting treatment. A patient in control group had a bone fracture, but no patients in bisphosphonate treatment groups had fractures or severe adverse effects. Conclusion: Intravenous alendronate is an effective treatment for osteoporosis in SMID patients.

Abnormality in GABAergic postsynaptic transmission associated with anxiety in Bronx waltzer mice with an Srrm4 mutation.

The homozygous Bronx waltzer (bv) mouse, which shows hearing impairment, also exhibits anxiety accompanied by a reduction in cortical parvalbumin (PV)-positive GABAergic interneurons. Recently, a mutation in splicing factor Ser/Arg repetitive matrix 4 (Srrm4) was found in bv mice. However, the cellular consequences of the Srrm4 mutation for anxiety remain unknown. Here, we tested our hypothesis that bv mutant primarily affects interneurons through a cell-intrinsic pathology that leads to a reduction of interneurons and consequently causes anxiety. We found that the anxiety becomes apparent at 6 weeks of age in bv/bv mice. However, in situ hybridization revealed that Srrm4 is not expressed in interneurons, but rather dominates in pyramidal neurons. In addition, the PV-positive GABAergic interneurons were not reduced in number in the bv/bv cortex when anxiety became evident. However, electrophysiological abnormality of GABAergic transmission from interneurons was concomitantly present. Pharmacological blockage of GABAA receptors revealed increased excitability in bv/bv mice, although no gross change occurred in the expression of an Srrm4-downstream gene, Kcc2, which regulates chloride flux upon GABAergic transmission. These findings suggest that the bv-associated Srrm4 mutation mainly involves post-synaptic GABAergic transmission in the central nervous system, which may be associated with the anxiety phenotype in bv/bv mice.

Evaluating Dysfunction in Fever-Induced Paroxysmal Weakness and Encephalopathy.

Heterozygous variants in the ATP1A3 gene are linked to well-known neurological phenotypes. There has been growing evidence for a separate phenotype associated with variants in residue Arg756-fever-induced paroxysmal weakness and encephalopathy (FIPWE) or relapsing encephalopathy with cerebellar ataxia (RECA). With only about 20 cases being reported, the clinical features associated with mutations at Arg756 have not been fully elucidated. We report a case of FIPWE with a p.Arg756Cys change in the ATP1A3 gene and a comparison of the clinical features, including electrophysiological examination, with previous cases. The 3-year-old male patient had normal psychomotor development, presenting with recurrent symptoms of generalized hypotonia with loss of gait, mutism, and dystonic movements only during febrile illnesses since 19 months of age. At 2.7 years of age, a third neurological decompensation episode occurred, during which electroencephalography (EEG) did not reveal high voltage slow waves or epileptiform discharge. Nerve conduction studies (NCS) also did not show latency delay or amplitude reduction. ATP1A3 exon sequencing showed a heterozygous p.Arg756Cys mutation. While the patient experienced repeated encephalopathy-like episodes, including severe hypotonia during febrile illness, EEG and NCS did not reveal any obvious abnormalities. These electrophysiological findings may represent an opportunity to suspect FIPWE and RECA.

Factors associated with the development of epilepsy in very low birth weight infants.

BACKGROUND: The survival rate of very low birth weight (VLBW) infants has recently improved. However, the occurrence of and factors associated with epilepsy in VLBW infants remain unknown. This study aimed to clarify the incidence, characteristics, and factors associated with epilepsy development in VLBW infants. METHODS: All VLBW infants admitted to our hospital between 2012 and 2017 were included in this study. VLBW infants with a follow-up period of <1 year were excluded. Chromosomal abnormalities, brain anomalies, severe intraventricular hemorrhage (IVH), cystic periventricular leukomalacia (PVL), and hypoxic ischemic encephalopathy (HIE) were considered to be risk factors. RESULTS: Epilepsy occurred in 21/526 (4.0%) VLBW infants. Chromosomal abnormalities, brain anomalies, severe IVH, cystic PVL, HIE, neonatal seizures, advanced maternal age, maternal diabetes mellitus, no administration of antenatal corticosteroids, and low Apgar scores at 1 and 5 min were associated with a risk of epilepsy. The median time to epilepsy onset was 8 months (range: 0-59 months), and the onset occurred within 2 years in 15/21 patients (71.4%) and within 4 years in 18/21 patients (85.7%). VLBW infants with risk factors developed epilepsy earlier and at a significantly higher rate than those without risk factors. Among infants who had risk factors and who developed epilepsy, 86.7% did so within 2 years of age, compared to 33.3% of those who developed epilepsy but did not have risk factors. CONCLUSION: These findings regarding factors associated with a risk of development of epilepsy and temporal feature of epilepsy may contribute to the development of monitoring and treatment protocols for epilepsy in VLBW infants.

Fibroblast growth factor signaling is required for the generation of oligodendrocyte progenitors from the embryonic forebrain.

Fibroblast growth factors (FGFs) comprise a family of developmental regulators implicated in a wide variety of neurological functions. FGF receptors 1, 2, and 3 (Fgfrs) are expressed in the embryonic forebrain, including regions overlapping with ventral sites of oligodendrocyte progenitor (OLP) generation. Although FGF signaling is known to influence the proliferation of OLPs in vitro, functions of different Fgfrs in vivo are lacking. Here, we examined single and double mutants with conditional disruption of Fgfrs, specifically in the embryonic forebrain, to investigate the effect of FGFs on the generation and proliferation of OLPs in vivo. FGF signaling, through cooperation between Fgfr1 and Fgfr2 but not Fgfr3, is required for the initial generation of OLPs in the mouse ventral forebrain, with Fgfr1 being a stronger inducer than Fgfr2. In cultures derived from embryonic mutant forebrains or from normal forebrains grown in the presence of Fgfr inhibitor, a strong attenuation of OLP generation was observed, supporting the role of FGF signaling in vivo. Contrary to in vitro findings, Fgfr1 and Fgfr2 signaling is not required for the proliferation of OLPs in vivo. Finally, failure of OLP generation in the Fgfr mutants occurred without loss of sonic hedgehog (Shh) signaling; and pharmacological inhibition of either Fgfr or hedgehog signaling in parallel cultures strongly inhibited OLP generation, suggesting that Fgfrs cooperate with Shh to generate OLPs. Overall, our results reveal for the first time an essential role of FGF signaling in vivo, where the three Fgfrs differentially control the normal generation of OLPs from the embryonic ventral forebrain.

Impairment of autonomic emotional response for executive function in children with ADHD: A multi-modal fNIRS and pupillometric study during the Wisconsin Card Sorting Test.

OBJECTIVE: Children with attention deficit hyperactivity disorder (ADHD) often experience difficulties with emotional control and a consequent inability to perform tasks. To clarify the effects of emotional behavior on cognitive functions, we aimed to determine the association between emotional changes and executive functions in children with ADHD by measuring the pupil diameter changes associated with emotional changes. PARTICIPANTS AND METHODS: This study included 14 children with ADHD and 10 typically developing children (TDC) aged between 10 and 16 years. During the Wisconsin Card Sorting Test (WCST), which is related to context formation and task switching among executive functions, changes in pupil diameter and frontal oxygenated hemoglobin (oxy-Hb) using functional near-infrared spectroscopy (fNIRS) were recorded simultaneously. Pupil diameter changes during "cognitive shift" and "consecutive correction" were compared between both groups. RESULTS: During cognitive shift, the pupils of children with ADHD contracted, whereas those of the TDC were mydriatic. During consecutive correction, the pupils of children with ADHD were mydriatic, whereas those of the TDC tended to contract. These results correlated with WCST performance. Moreover, during cognitive shifts, changes in bilateral frontal blood flow were increased in TDC, but not in children with ADHD. CONCLUSION: The locus coeruleus-norepinephrine (LC-NE) system plays an important role in pupillary diameter response. These results suggest that the LC-NE system may be dysfunctional in children with ADHD, and the system's abnormality may lead to affective abnormalities in such patients, which results in poor performance on WCST (i.e., impaired executive functions).

Arterial spin labeling perfusion imaging in an infant with anti-N-methyl-D-aspartate receptor encephalitis: A case report.

BACKGROUND: Anti-N-methyl-d-aspartate receptor (NMDAR) encephalitis is an autoimmune encephalitis characterized by complex neuropsychiatric syndromes and the presence of cerebrospinal fluid (CSF) antibodies against NMDAR. The characteristics of anti-NMDAR encephalitis in children, particularly infants, are unclear due to difficulties in neurologic assessment such as psychiatric symptoms. Additionally, subtle or non-specific findings of conventional magnetic resonance imaging (MRI) make early diagnosis even more difficult. Herein, we present the first case of infant anti-NMDAR encephalitis in which perfusion imaging demonstrated marked abnormalities and the absence of conventional MRI findings. CASE PRESENTATION: The patient was an 11-month-old boy who was admitted because of seizure and prolonged fever. He presented with involuntary movements of the mouth and tongue. Brain MRI showed no morphological abnormalities, but three-dimensional arterial spin labeling (ASL) perfusion imaging showed reduced blood flow in the left temporal and frontal regions and the right cerebellum. After that, a positive anti-NMDAR antibody test result was received. Despite treatment with IVIG and methylprednisolone, the involuntary movements and autonomic dysfunction gradually became more prominent. After rituximab administration, the clinical symptoms improved slightly, and follow-up MRI revealed diffuse brain atrophy and improvement in the balance of brain perfusion. CONCLUSIONS: To the best of our knowledge, this is the first case report of infantile anti-NMDAR encephalitis in which cerebral blood flow was evaluated using three-dimensional ASL perfusion imaging. Indeed, our case, which showed abnormalities only in ASL perfusion imaging, suggests that CBF assessment could aid in the early diagnosis of anti-NMDAR encephalitis in infants.

Detection of deviance in Japanese kanji compound words.

Reading fluency is based on the automatic visual recognition of words. As a manifestation of the automatic processing of words, an automatic deviance detection of visual word stimuli can be observed in the early stages of visual recognition. To clarify whether this phenomenon occurs with Japanese kanji compounds-since their lexicality is related to semantic association-we investigated the brain response by utilizing three types of deviants: differences in font type, lexically correct or incorrect Japanese kanji compound words and pseudo-kanji characters modified from correct and incorrect compounds. We employed magnetoencephalography (MEG) to evaluate the spatiotemporal profiles of the related brain regions. The study included 22 adult native Japanese speakers (16 females). The abovementioned three kinds of stimuli containing 20% deviants were presented during the MEG measurement. Activity in the occipital pole region of the brain was observed upon the detection of font-type deviance within 250 ms of stimulus onset. Although no significant activity upon detecting lexically correct/incorrect kanji compounds or pseudo-kanji character deviations was observed, the activity in the posterior transverse region of the collateral sulcus (pCoS)-which is a fusiform neighboring area-was larger when detecting lexically correct kanji compounds than when detecting pseudo-kanji characters. Taken together, these results support the notion that the automatic detection of deviance in kanji compounds may be limited to a low-level feature, such as the stimulus stroke thickness.

Effect of anti-attention-deficit hyperactivity disorder (ADHD) medication on clinical seizures and sleep EEG: A retrospective study of Japanese children with ADHD.

AIMS: Patients with attention-deficit hyperactivity disorder (ADHD) often exhibit basic or paroxysmal wave abnormalities on electroencephalography (EEG). Methylphenidate (MPH), an anti-ADHD stimulant, has been reported to lower the seizure threshold. However, there have been no reports comparing EEG changes before and after administration of the central nervous system (CNS) stimulant MPH, or atomoxetine (ATX) hydrochloride, a non-CNS stimulant. In this study, we investigated changes in sleep EEG before and after the administration of ADHD treatment drugs. METHOD: With the approval of the ethics committee, the medical records of 28 children with ADHD (23 men and 5 women) who gave consent were retrospectively investigated. The appearance of sudden abnormal waves during a 10-minute sleep EEG recording was measured in 0.1-second units, and the duration of these waves was calculated as the paroxysmal index (PI). RESULTS: Paroxysmal index did not differ significantly between patients who received MPH and those who received ATX. In addition, there were no exacerbations of clinical seizures. CONCLUSION: It was concluded that ADHD medications do not have an adverse effect on epileptic seizures or abnormal sleep EEGs.

Postoperative improvement of executive function and adaptive behavior in children with intractable epilepsy.

INTRODUCTION: An alteration in postoperative cognitive function varies according to the patients' background characteristics, such as etiology, focus, and seizure duration. Accurate prediction and assessment of postoperative cognitive function is difficult in each patient. Adaptive behavior could describe the typical performance of daily activities and represents the ability to translate cognitive potential into real-world skills. We examined the relationship between alterations of executive function (EF) and adaptive behavior in school children undergoing surgery for intractable epilepsy. METHODOLOGY: We enrolled 31 children with focal resection or corpus callosotomy for intractable epilepsy [mean age at surgery, 12.5 years; 16 boys; mean intellectual quotient, 73.3]. We surveyed answered questionnaires on attention-deficit hyperactivity disorder (ADHD), autism spectrum disorder (ASD), and adaptive behavior using the Vineland Adaptive Behavior Scale, 2nd edition (VABS-II), and performed continuous performance tests (CPTs) on children pre- and postoperatively. RESULT: ADHD and ASD symptoms improved after epilepsy surgery. The omission error (OE) in the CPT variable improved after epilepsy surgery, especially in children with a shorter preoperative period. Improved ASD symptoms led to an increased score of the coping skills subdomain. The reduced OE observed after surgery also increased the score of the community skills subdomain. CONCLUSION: Improvement in EF and ASD symptoms resulted in better adaptive behavior postoperatively. These results were important for the pre- and postoperative evaluation and re-evaluation of children with epilepsy requiring special education and related services.

[A case of recurrent paraneoplastic cerebellar ataxia with antibodies to GluR epsilon 2 causally related to ganglioneuroma].

Acute cerebellar ataxia (ACA) in childhood following viral infection is a self-limited disease. We present a boy with recurrent episodes of paraneoplastic cerebellar ataxia associated with a ganglioneuroma. A 20-month-old boy developed the first episode of cerebellar ataxia after nonspecific respiratory tract infections. During this episode he showed a wide gait and truncal ataxia with intention tremor and horizontal nystagmus. Our initial diagnosis was ACA, and gradual improvement of ataxia was observed thereafter. At 2 years and 6 months, similar cerebellar symptoms recurred after respiratory tract infections. Speech difficulty and cognitive problems developed thereafter. We suspected paraneoplastic syndrome. Computed tomography revealed a retroperitoneal tumor, and autoantibodies against GluR epsilon 2 were detected in the cerebrospinal fluid. After the tumor resection, the cerebellar symptoms did not recur and speech difficulty and cognitive problems improved gradually. Recent neuroimaging and neuropsychological studies have revealed that cerebellar function contributes to higher brain functions including cognition and learning. We will follow up this patient's long-term cognitive function and consider special educational support and programs.

Atypical gamma functional connectivity pattern during light sleep in children with attention deficit hyperactivity disorder.

INTRODUCTION: We examined functional connectivity analyses in electroencephalograms (EEGs) of patients with attention deficit hyperactivitydisorder (ADHD) and in those of typically developing children (TDC) to uncover neurobiological abnormalities. METHODOLOGY: We enrolled 31 children with ADHD (mean age 11.1 years; 23 boys) and 17 sex-, age-, and intelligence-matched TDC to undergo 19-channel EEGs during light sleep. We estimated functional connectivity using the phase lag index (PLI) and coherence measurements that capture the synchronization of EEG signals and graphed metrics with GRETNA. We also performed continuous performance tests (CPTs) on the children and obtained answered questionnaires on ADHD and autism spectrum disorder. RESULTS: The central-to-posterior gamma PLI was lower in children with ADHD than that in TDC. The other PLI frequency bands and all coherence frequency bands were not statistically different between both groups. Individuals with high hyperactivity scores on questionnaires and low reaction times (SDs) on CPT had low motor and occipital pairs of gamma PLIs. Graph metrics showed no differences between the groups. CONCLUSIONS: The difference in averaged gamma PLI (especially with motor and occipital pairs) between groups was more suitable for diagnosis than the averaged coherence. Lower averaged gamma PLIs reflected more severe ADHD symptoms. A prospective study with more controlled conditions is warranted to determine if gamma-band PLI can be used as an auxiliary tool for ADHD diagnosis.

Reduced Nogo-P3 in adults with developmental coordination disorder (DCD).

Nogo-N2 is associated with the premotor cognitive process that precedes motor response (e.g., conflict monitoring), whereas Nogo-P3 is related to the inhibition of the actual motor response. We examined the influence of motor clumsiness of developmental coordination disorder (DCD) on components of the event-related potential in a Go/Nogo task. Participants were healthy adults (N = 81) that were classified into control and DCD groups based on the Movement Assessment Battery for Children Second Edition. We manipulated the difficulty in stopping a response by varying the frequency of Nogo stimuli in a response task into rare (20%) and frequent (80%) conditions, and Nogo-N2 and Nogo-P3 were calculated from electroencephalograms (EEGs) during the Go/Nogo tasks. The commission error rate in the rare condition was significantly higher in the DCD group than in the control group, indicating that motor clumsiness decreases task performance. There were no differences in Nogo-N2 between DCD and control groups. However, Nogo-P3 in the rare condition was reduced in the DCD group compared to the control group. These results suggest that the influence of motor clumsiness is limited to the cognitive process after the initiation of the actual motor response.