A mutation in DOK7 in congenital myasthenic syndrome forms aggresome in cultured cells, and reduces DOK7 expression and MuSK phosphorylation in patient-derived iPS cells.

At the neuromuscular junction, the downstream of tyrosine kinase 7 (DOK7) enhances the phosphorylation of muscle-specific kinase (MuSK) and induces clustering of acetylcholine receptors (AChRs). We identified a patient with congenital myasthenic syndrome (CMS) with two heteroallelic mutations in DOK7, c.653-1G>C in intron 5 and c.190G>A predicting p.G64R in the pleckstrin homology domain. iPS cells established from the patient (CMS-iPSCs) showed that c.653-1G>C caused in-frame skipping of exon 6 (120 bp) and frame-shifting activation of a cryptic splice site deleting seven nucleotides in exon 6. p.G64R reduced the expression of DOK7 to 10% of wild-type DOK7, and markedly compromised AChR clustering in transfected C2C12 myotubes. p.G64R-DOK7 made insoluble aggresomes at the juxtanuclear region in transfected C2C12 myoblasts and COS7 cells, which were co-localized with molecules in the autophagosome system. A protease inhibitor MG132 reduced the soluble fraction of p.G64R-DOK7 and enhanced the aggresome formation of p.G64R-DOK7. To match the differentiation levels between patient-derived and control induced pluripotent stem cells (iPSCs), we corrected c.190G>A (p.G64R) by CRISPR/Cas9 to make isogenic iPSCs while retaining c.653-1G>C (CMS-iPSCsCas9). Myogenically differentiated CMS-iPSCs showed juxtanuclear aggregates of DOK7, reduced expression of endogenous DOK7 and reduced phosphorylation of endogenous MuSK. Another mutation, p.T77M, also made aggresome to a less extent compared with p.G64R in transfected COS7 cells. These results suggest that p.G64R-DOK7 makes aggresomes in cultured cells and is likely to compromise MuSK phosphorylation for AChR clustering.

Involvement of brain structures in childhood epilepsy with centrotemporal spikes.

BACKGROUND: We aimed to investigate electroencephalography (EEG)-functional magnetic resonance imaging (fMRI) findings to elucidate the interictal epileptiform discharge (IED)-related functional alterations in deep brain structures and the neocortex in childhood epilepsy with centrotemporal spikes (CECTS). METHODS: Ten children with CECTS (median age 8.2 years), referred to our hospital within a year of onset, were eligible for inclusion. They underwent EEG-fMRI recording during sleep. Llongitudinal evaluations, including medical examinations, intelligence tests, and questionnaires about developmental disabilities, were performed. The initial evaluation was performed at the same time as the EEG-fMRI, and the second evaluation was performed over 2 years after the initial evaluation. RESULTS: Three children were unable to maintain sleep during the EEG-fMRI recording, and the remaining seven children were eligible for further assessment. All patients showed unilateral-dominant centrotemporal spikes during scans. One patient had only positive hemodynamic responses, while the others had both positive and negative hemodynamic responses. All patients showed IED-related hemodynamic responses in the bilateral neocortex. For deep brain structures, IED-related hemodynamic responses were observed in the cingulate gyrus (n = 4), basal ganglia (n = 3), thalamus (n = 2), and default mode network (n = 1). Seizure frequencies at the second evaluation were infrequent or absent, and the longitudinal results of intelligence tests and questionnaires were within normal ranges. CONCLUSIONS: We demonstrated that IEDs affect broad brain areas, including deep brain structures such as the cingulate gyrus, basal ganglia, and thalamus. Deep brain structures may play an important role in the pathophysiology of CECTS.

Risks of ACTH therapy for West syndrome following BCG vaccination.

OBJECTIVE: Bacille de Calmette et Guérin (BCG) is a live vaccine for tuberculosis that is administered to all infants in Japan. Adrenocorticotropic hormone (ACTH) therapy for West syndrome (WS) causes immunosuppression and may result in BCG infection after BCG vaccination. We evaluated the safety of ACTH therapy initiated shortly after BCG vaccination. METHODS: We analyzed patients with WS who received ACTH therapy between 2005 and 2018. We evaluated the interval between BCG and ACTH therapy, and the rate of BCG infection during and after ACTH therapy, by retrospective chart review. RESULTS: Seventy-nine patients were included in the analysis. Twenty-three patients received ACTH therapy prior to BCG vaccination. For the remaining 56 patients, the median interval between BCG vaccination and the start of ACTH therapy (BCG-ACTH interval) was 91.5 (range 14-280) days. The BCG-ACTH interval was shorter in patients with unknown than in those with known etiologies. It was <8 weeks in 13 patients (10 with unknown and 3 with known etiologies). The minimum BCG-ACTH interval was 14 days. Six patients with epileptic spasms received BCG vaccinations because physicians did not recognize their seizures. None of the patients developed BCG infection. CONCLUSION: No patients who received ACTH therapy after BCG, even at an interval of 8 weeks, developed BCG infection. The timing of ACTH therapy initiation should be based on the risk of BCG-related adverse events and the adverse effects of any delay.

Repetitive sleep starts: An important differential diagnosis of infantile spasms.

OBJECTIVE: Repetitive sleep starts (RSS) are clusters of nonepileptic, spasm-like movements occurring during sleep onset. However, their characteristics have yet to be defined. We conducted a clinicoelectroencephalographic study of children with RSS to clarify their detailed characteristics. METHODS: To differentiate starts from epileptic spasms, we recruited children with brief "crescendo-decrescendo" muscle contractions that simultaneously involved the limbs and trunk without electroencephalogram changes, and that fulfilled the following criteria: (1) repeated occurrence (five or more) and (2) manifestation during sleep stage N1-N2. A total of nine children met these criteria. Their clinical information and video-electroencephalogram data were analyzed retrospectively. RESULTS: The background conditions observed at onset of RSS were perinatal hypoxic-ischemic encephalopathy (n = 4), West syndrome of unknown etiology (n = 1), and traumatic brain injury (n = 1). The age at onset of RSS, the number of starts in a given RSS cluster, the interval between starts, and the duration of surface electromyogram activity were between 3 and 46 months, 5 and 547, <1 and 60 s, and 0.3 and 5.4 s, respectively. None of the median value of these parameters differed between children with and without corticospinal tract injury. During the median follow-up period of 33 months, RSS disappeared spontaneously in five. CONCLUSION: This is the largest case series of RSS clarifying their clinicoelectroencephalographic characteristics reported to date. To avoid unnecessary antiepileptic therapies, clinicians should be aware of RSS and distinguish it from other disorders involving involuntary movements or seizures, especially epileptic spasms.

Pseudo-sawtooth pattern on amplitude-integrated electroencephalography in neonatal hypoxic-ischemic encephalopathy.

OBJECTIVE: The objective of this study was to describe a novel amplitude-integrated electroencephalography (aEEG) pattern in infants with hypoxic-ischemic encephalopathy (HIE) and to assess the clinical significance. METHODS: The aEEG traces of infants with HIE who were treated with therapeutic hypothermia (TH) from 2012 to 2017 were analyzed. A pseudo-sawtooth (PST) pattern was defined as a periodic increase of the upper and/or lower margin of the trace on aEEG without showing seizure activities on conventional EEG (CEEG). RESULTS: Of the 46 infants, 6 (13%) had the PST pattern. The PST pattern appeared following a flat trace or a continuous low-voltage pattern and was followed by a burst-suppression pattern. On CEEG, the PST pattern consists of alternating cycles of low-voltage irregular activities and almost flat tracing. The PST pattern was associated with neuroimaging abnormalities and with various degrees of neurodevelopmental outcomes. Positive predictive values of the PST or worse pattern for adverse outcomes were high at 12 h after birth. CONCLUSION: A novel aEEG background pattern in infants with HIE was reported. The PST pattern likely indicates a suppressed background pattern and may be linked to unfavorable outcomes. Further multicenter validation study is needed to clarify its clinical significance.

Evaluation of interobserver variability in application of the new neonatal seizure classification proposed by the ILAE Task Force.

OBJECTIVE: Clinical identification of neonatal seizures (NS) remains challenging. The International League Against Epilepsy (ILAE) Task Force on Neonatal Seizures has proposed a new classification of NS, based on the 2017 ILAE seizure classification. One of the key points of this proposed NS classification is that seizure types should be determined by the "predominant" clinical feature. However, when the definition of "predominant" is uncertain, interobserver variability may arise. METHODS: We asked 49 health professionals to classify 21 NS video-electroencephalogram (EEG) recordings using the proposed 9 seizure types. RESULTS: The degree of agreement among participants was low, and agreement was weak among experts in neonatal neurology. Among experts, the rate of agreement was <50% for 2 NS. This disagreement was related to differences in the interpretation of "predominant features." Although interobserver variability was present among users of the new NS classification, the reproducibility of the NS classification was satisfactory. CONCLUSION: Education designed to foster consistent application of the standards for NS will be important for reducing interobserver variability and expanding the use of the new NS classification.

Hippocampal diffusion abnormality after febrile status epilepticus is related to subsequent epilepsy.

OBJECTIVE: To assess hippocampal signal changes on diffusion-weighted imaging (DWI) during the acute period after febrile status epilepticus (FSE) and to examine the relationship between DWI and subsequent epilepsy. METHODS: A prospective, multicenter study of children with a first episode of FSE was performed. The patients underwent magnetic resonance imaging (MRI) within 3 days of FSE, and signal intensity was evaluated on DWI. Electroencephalography studies within 3 days of FSE were also assessed. Nine to 13 years after FSE, information on subsequent epilepsy was obtained. RESULTS: Twenty-two children with FSE were evaluated. DWI showed unilateral hippocampal hyperintensity in six patients (27%). Three of six patients with hippocampal hyperintensity had ipsilateral thalamic hyperintensity. On EEG within 3 days of FSE, five of six patients with hippocampal hyperintensity had ipsilateral focal slowing, spikes, or attenuation. Nine to 13 years later, the outcomes could be determined in five patients with hippocampal hyperintensity and in 10 without. All 5 patients with hippocampal hyperintensity had hippocampal atrophy and developed focal epilepsy, whereas only 1 of 10 patients without hippocampal hyperintensity developed epilepsy (P = 0.002). Ictal semiology was concordant with temporal lobe seizures in all patients. Ipsilateral temporal epileptiform abnormalities were seen on EEG in four of five at last follow-up. SIGNIFICANCE: Acute DWI hippocampal hyperintensity was seen in 27% of patients with FSE. Acute DWI hyperintensity suggests cytotoxic edema caused by prolonged seizure activity. Hippocampal DWI hyperintensity is related to mesial temporal lobe epilepsy and can be a target of neuroprotective treatments to prevent the onset of epilepsy.

Cytotoxic edema at onset in West syndrome of unknown etiology: A longitudinal diffusion tensor imaging study.

OBJECTIVE: To clarify longitudinal changes in white matter microstructures from the onset of disease in patients with West syndrome (WS) of unknown etiology. METHODS: Diffusion tensor imaging (DTI) was prospectively performed at onset and at 12 and 24 months old in 17 children with WS of unknown etiology. DTI was analyzed using tract-based spatial statistics (TBSS) and tract-specific analysis (TSA) of 13 fiber tracts, and fractional anisotropy (FA) and mean diffusivity (MD) were compared with those of 42 age-matched controls. Correlations of FA and MD with developmental quotient (DQ) at age 24 months were analyzed. Multiple comparisons were adjusted for using the false discovery rate (q-value). RESULTS: TBSS analysis at onset showed higher FA and lower MD in the corpus callosum and brainstem in patients. TSA showed lower MD in bilateral uncinate fasciculi (UF) (right: q < 0.001; left: q = 0.03) at onset in patients. TBSS showed a negative correlation between FA at onset and DQ in the right frontal lobe, whereas FA at 24 months old exhibited a positive correlation with DQ in the diffuse white matter. MD for bilateral UF at 24 months old on TSA correlated positively with DQ (q = 0.04, both). SIGNIFICANCE: These findings may indicate the existence of cytotoxic edema in the immature white matter and dorsal brainstem at onset, and subsequent alterations in the diffuse white matter in WS of unknown etiology. Microstructural development in the UF might play important roles in cognitive development in WS.

LRP4 third ß-propeller domain mutations cause novel congenital myasthenia by compromising agrin-mediated MuSK signaling in a position-specific manner.

Congenital myasthenic syndromes (CMS) are heterogeneous disorders in which the safety margin of neuromuscular transmission is compromised by one or more specific mechanisms. Using Sanger and exome sequencing in a CMS patient, we identified two heteroallelic mutations, p.Glu1233Lys and p.Arg1277His, in LRP4 coding for the postsynaptic low-density lipoprotein receptor-related protein 4. LRP4, expressed on the surface of the postsynaptic membrane of the neuromuscular junction, is a receptor for neurally secreted agrin, and LRP4 bound by agrin activates MuSK. Activated MuSK in concert with Dok-7 stimulates rapsyn to concentrate and anchor AChR on the postsynaptic membrane and interacts with other proteins implicated in the assembly and maintenance of the neuromuscular junction. LRP4 also functions as an inhibitor of Wnt/beta-catenin signaling. The identified mutations in LRP4 are located at the edge of its 3rd beta-propeller domain and decrease binding affinity of LRP4 for both MuSK and agrin. Mutations in the LRP4 3rd beta-propeller domain were previously reported to impair Wnt signaling and cause bone diseases including Cenani-Lenz syndactyly syndrome and sclerosteosis-2. By analyzing naturally occurring and artificially introduced mutations in the LRP4 3rd beta-propeller domain, we show that the edge of the domain regulates the MuSK signaling whereas its central cavity governs Wnt signaling. We conclude that LRP4 is a new CMS disease gene and that the 3rd beta propeller domain of LRP4 mediates the two signaling pathways in a position-specific manner.

Recurrent bacteremia with different strains of Streptococcus pyogenes in an immunocompromised child.

We report an immunocompromised child who experienced two episodes of bacteremia due to Streptococcus pyogenes. Random amplification of polymorphic DNA profiles, emm genotypes, superantigen profiles, antimicrobial susceptibility, and resistance-related genes were investigated, and the results showed different profiles between the two isolates. This is the first report describing recurrent bacteremia caused by different strains of S. pyogenes.

Epileptic foci and networks in children with epilepsy after acute encephalopathy with biphasic seizures and late reduced diffusion.

BACKGROUND: Acute encephalopathy with biphasic seizures and late reduced diffusion (AESD) develops along with status epilepticus and widespread subcortical white matter edema. We aimed to evaluate the epileptic foci and networks in two patients with epilepsy after AESD using simultaneous electroencephalography and functional magnetic resonance imaging (EEG-fMRI). METHODS: Statistically significant blood oxygen level-dependent (BOLD) responses related to interictal epileptiform discharges (IEDs) were analyzed using an event-related design of hemodynamic response functions with multiple peaks. RESULTS: Patient 1 developed focal seizures at age 10 years, one year after AESD onset. Positive BOLD changes were observed in the bilateral frontotemporal lobes, left parietal lobe, and left insula. BOLD changes were also observed in the subcortical structures. Patient 2 developed epileptic spasms at age two years, one month after AESD onset. Following total corpus callosotomy (CC) at age three years, the epileptic spasms resolved, and neurodevelopmental improvement was observed. Before CC, positive BOLD changes were observed bilaterally in the frontotemporal lobes. BOLD changes were also observed in the subcortical structures. After CC, the positive BOLD changes were localized in the temporal lobe ipsilateral to the IEDs, and the negative BOLD changes were mainly in the cortex and subcortical structures of the hemisphere ipsilateral to IEDs. CONCLUSION: EEG-fMRI revealed multiple epileptic foci and extensive epileptic networks, including subcortical structures in two cases with post-AESD epilepsy. CC may be effective in disconnecting the bilaterally synchronous epileptic networks of epileptic spasms after AESD, and pre-and post-operative changes in EEG-fMRI may reflect improvements in epileptic symptoms.

Color density spectral array findings on continuous EEG during therapeutic hypothermia in children with acute encephalopathy.

BACKGROUND: Quantitative EEG is frequently used to monitor children affected by acute encephalopathy (AE), with the expectation of providing comprehensive insights into continuous EEG monitoring. However, the potential of quantitative EEG for estimating outcomes in this context remains unclear. We sought reliable prognostic markers within the color density spectral array (CDSA) of the continuous EEG for AE-affected children undergoing therapeutic hypothermia (TH). METHODS: This retrospective study analyzed CDSA data from eight scalp electrodes of 15 AE-affected children undergoing TH. Two CDSA features were investigated-high-frequency lines (HFLs) and periodic elevation in the low frequency band (PLFB)-along with the corresponding EEG characteristics. The inter-rater reliability for CDSA was assessed by four pediatric neurologists. Outcomes were grouped into either no/mild or severe decline in motor and cognitive functions, then compared with CDSA features. RESULTS: The median EEG recording time was 114 (81-151) h per child. While at least 41 % of HFLs corresponded to typical sleep spindles, 94 % of PLFB aligned with cyclic changes in the amplitude of delta/theta waves on the raw EEG. Inter-rater reliability was higher for HFLs than for PLFB (kappa values: 0.69 vs. 0.46). HFLs were significantly more prevalent in children with no/mild decline than in children with severe decline (p = 0.017), whereas PLFB did not differ significantly (p = 0.33). CONCLUSIONS: This study provides preliminary evidence that reduced HFLs on CDSA predict unfavorable outcomes in AE-affected children undergoing TH. This suggests that maintaining high-frequency waves is critical for optimal brain function.

Underlying Disorders in Children With Infection-Related Acute Encephalopathy.

BACKGROUND: Various factors contribute to the development of infection-related acute encephalopathy (AE) in children, such as infectious agents and chronic underlying disorders. We studied underlying disorders in children with AE to identify predisposing factors of AE. METHODS: We investigated underlying disorders or past histories in patients with two types of AE from the database in the Tokai area of Japan between 2009 and 2022: 204 patients with AE with reduced subcortical diffusion (AED) and 137 with clinically mild encephalopathy with a reversible splenial lesion (MERS). We compared them with 89 patients with acute disseminated encephalomyelitis (ADEM) to clarify the specific disorders in the two AE types. RESULTS: The prevalence of underlying disorders in AED (34%, 70 patients) was significantly higher than that in ADEM (12%, 11 patients) (P < 0.01). The prevalence of underlying disorders in MERS was 23% (32 patients). The underlying disorders included seizure disorders, premature birth, genetic/congenital disorders, and endocrine/renal diseases. In patients with seizure disorders in AED, five patients (18%) had Dravet syndrome and four (15%) had West syndrome, whereas none with MERS had these syndromes. Twenty-five (12%) of 204 patients with AED, three (2%) with MERS, and one (1%) with ADEM were preterm or low birth weight. CONCLUSIONS: The high prevalence of seizure disorders suggests that seizure susceptibility is an important predisposing factor in AED. Premature birth also has an impact on the development of AED. Caution is required regarding the development of AE in patients with chronic seizure disorders or premature birth.

Sleep state-dependent development of resting state functional connectivity during the preterm period.

STUDY OBJECTIVES: The brains of preterm infants exhibit altered functional connectivity (FC) networks, but the potential variation in sleep states and the impact of breathing patterns on FC networks are unclear. This study explores the evolution of resting-state FC from preterm to term, focusing on breathing patterns and distinguishing between active sleep and quiet sleep. METHODS: We recruited 63 preterm infants and 44 healthy-term infants and performed simultaneous electroencephalography and functional near-infrared spectroscopy. FC was calculated using oxy- and deoxyhemoglobin signals across eight channels. First, FC was compared between periodic breathing (PB) and non-PB segments. Then sleep state-dependent FC development was explored. FC was compared between active sleep and quiet sleep segments and between preterm infants at term and term-born infants in each sleep state. Finally, associations between FC at term, clinical characteristics, and neurodevelopmental outcomes in late infancy were assessed in preterm infants. RESULTS: In total, 148 records from preterm infants and 44 from term-born infants were analyzed. PB inflated FC values. After excluding PB segments, FC was found to be elevated during active sleep compared to quiet sleep, particularly in connections involving occipital regions. Preterm infants had significantly higher FC in both sleep states compared to term-born infants. Furthermore, stronger FC in specific connections during active sleep at term was associated with unfavorable neurodevelopment in preterm infants. CONCLUSIONS: Sleep states play a critical role in FC development and preterm infants show observable changes in FC.

Mutations in the C-terminal domain of ColQ in endplate acetylcholinesterase deficiency compromise ColQ-MuSK interaction.

Acetylcholinesterase (AChE) at the neuromuscular junction (NMJ) is mostly composed of an asymmetric form in which three tetramers of catalytic AChE subunits are linked to a triple helical collagen Q (ColQ). Mutations in COLQ cause endplate AChE deficiency. We report three patients with endplate AChE deficiency with five recessive COLQ mutations. Sedimentation profiles showed that p.Val322Asp and p.Arg227X, but not p.Cys444Tyr, p.Asp447His, or p.Arg452Cys, inhibit formation of triple helical ColQ. In vitro overlay of mutant ColQ-tailed AChE on muscle sections of Colq(-/-) mice revealed that p.Cys444Tyr, p.Asp447His, and p.Arg452Cys in the C-terminal domain (CTD) abrogate anchoring ColQ-tailed AChE to the NMJ. In vitro plate-binding assay similarly demonstrated that the three mutants inhibit binding of ColQ-tailed AChE to MuSK. We also confirmed the pathogenicity of p.Asp447His by treating Colq(-/-) mice with adeno-associated virus serotype 8 carrying mutant COLQ-p.Asp447His. The treated mice showed no improvement in motor functions and no anchoring of ColQ-tailed AChE at the NMJ. Electroporation of mutant COLQ harboring p.Cys444Tyr, p.Asp447His, and p.Arg452Cys into anterior tibial muscles of Colq(-/-) mice similarly failed to anchor ColQ-tailed AChE at the NMJ. We proved that the missense mutations in ColQ-CTD cause endplate AChE deficiency by compromising ColQ-MuSK interaction at the NMJ.

Impaired gating of γ- and ε-AChR respectively causes Escobar syndrome and fast-channel myasthenia.

OBJECTIVE: To dissect the kinetic defects of acetylcholine receptor (AChR) γ subunit variant in an incomplete form of the Escobar syndrome without pterygium and compare it with those of a variant of corresponding residue in the AChR ε subunit in a congenital myasthenic syndrome (CMS). METHODS: Whole exome sequencing, α-bungarotoxin binding assay, single channel patch-clamp recordings, and maximum likelihood analysis of channel kinetics. RESULTS: We identified compound heterozygous variants in AChR γ and ε subunits in three Escobar syndrome (1-3) and three CMS patients (4-6), respectively. Each Escobar syndrome patient carries γP121R along with γV221Afs*44 in patients 1 and 2, and γY63* in patient 3. Three CMS patients share εP121T along with εR20W, εG-8R, and εY15H in patients 4, 5, and 6, respectively. Surface expressions of γP121R- and εP121T-AChR were 80% and 138% of the corresponding wild-type AChR, whereas εR20W, εG-8R, and εY15H reduced receptor expression to 27%, 35%, and 30% of wild-type εAChR, respectively. γV221Afs*44 and γY63* are null variants. Thus, γP121R and εP121T determine the phenotype. γP121R and εP121T shorten channel opening burst duration to 28% and 18% of corresponding wild-type AChR by reducing the channel gating equilibrium constant 44- and 63-fold, respectively. INTERPRETATION: Similar impairment of channel gating efficiency of a corresponding P121 residue in the acetylcholine-binding site of the AChR γ and ε subunits causes Escobar syndrome without pterygium and fast-channel CMS, respectively, suggesting that therapy for the fast-channel CMS will benefit Escobar syndrome.

Pathological gait in Rett syndrome: Quantitative evaluation using three-dimensional gait analysis.

OBJECTIVES: Ataxic-rigid gait is a characteristic gait pathology in patients with Rett syndrome (RTT). In the present study, we aimed to quantitatively evaluate gait pathology in patients with RTT using three-dimensional gait analysis (3DGA). METHODS: We performed 3DGA in 11 patients with RTT ranging from 5 to 18 years (median age, 9 years) and in 33 age-matched healthy female controls. We compared the results of 3DGA, including spatiotemporal gait parameters and comprehensive indices of gait kinematics, such as the Gait Deviation Index (GDI) and Gait Profile Score (GPS), between the two groups. The GPS consists of nine sub-indices called Gait Variable Scores (GVSs). Decline in GDI or elevation of GPS and GVS indicated greater abnormal gait pathology. RESULTS: The patients demonstrated significantly slower walking speed, lower step length/length of the lower extremities, lower cadence, wider step width, and higher coefficient of variation of step length than the controls. Moreover, the patients had a lower GDI and higher GPS than the controls. The patients also exhibited higher GVSs for eight out of nine gait kinematics, particularly the sagittal plane in the pelvis, hip, knee, and ankle joint; coronal plane in the pelvis and hip joint; and horizontal plane in the pelvis than the controls. CONCLUSIONS: Quantitative evaluation of gait pathology in patients with RTT is possible using 3DGA. We found that in addition to ataxic-rigid gait, abnormalities in the coronal plane of the pelvis and hip joint and the horizontal plane of the pelvis were prominent.

Two Cases of Juvenile Myelomonocytic Leukemia and Myelin Oligodendrocyte Glycoprotein Antibody-Associated Disease.

BACKGROUND: Myelin oligodendrocyte glycoprotein (MOG) antibody-associated disease (MOGAD) is an autoimmune demyelinating disorder that often manifests after infections or vaccinations. We report two patients who developed MOGAD out of eight patients with juvenile myelomonocytic leukemia (JMML) that has never been reported. METHODS: We investigated two patients with JMML who developed MOGAD among 127 patients with leukemia from 2012 to 2021. RESULTS: Patient 1 was treated for JMML and developed fever and impaired consciousness at two years and one month of age. Magnetic resonance imaging revealed high-intensity lesions in the left frontal and left occipital white matter. The serum anti-MOG antibody test was positive, while the test was negative in the stored serum 45 days before the onset of encephalopathy. He had relapse of MOGAD after steroid therapy and plasmapheresis. Patient 2, who was treated for JMML, became apathetic and mute at three years and seven months of age. Magnetic resonance imaging revealed left frontoparietal subcortical high-intensity lesions. Anti-MOG antibody at the onset of encephalopathy was positive, while it was negative in stored serum 57 days before and 47 days after the onset. CONCLUSION: We treated two patients who developed MOGAD out of eight patients with JMML and none with MOGAD out of 119 patients with acute lymphocytic leukemia, acute myelocytic leukemia, or chronic myelocytic leukemia. The activated autoimmune process via the RAS pathway abnormality may have led to the formation of the anti-MOG antibody and the onset of MOGAD. MOGAD can occur in children with JMML, and abnormalities of the RAS pathway possibly contribute to its onset.

[Clinical features of congenital myasthenic syndrome in Japan].

OBJECTIVE: We examined the clinical and neurophysiological features of Japanese patients with congenital myasthenic syndrome (CMS). METHOD: Subjects were five patients who were diagnosed with CMS on the basis of clinical course, repetitive nerve stimulation (RNS), and genetic analysis. RESULTS: Four patients manifested motor retardation within one year of birth, while one manifested motor intolerance at three years of age. The most characteristic symptom observed in all the patients was fluctuating muscle weakness, which varied on a daily basis or continued for several days after the late infancy period. Only one patient manifested daily fluctuation of muscle weakness. RNS of the accessory nerve evoked a decrementing response in three patients who were examined;however, RNS of the median, ulnar, and tibial nerves (one patient each) did not evoke such responses. After the edrophonium chloride test, no improvement was seen even if the patients manifested ptosis. For judgment of this test, improvement in decrementing rate observed while performing RNS was useful. All five patients who were administered medication based on the results of genetic analysis demonstrated an improvement in their symptoms. CONCLUSION: We suggest that CMS can be diagnosed based on careful examination and electrophysiological results. CMS is a treatable disorder, and therefore, correct diagnosis is important.