Missense variant c.1460 T > C (p.L487P) enhances protein degradation of ER mannosyltransferase ALG9 in two new ALG9-CDG patients presenting with West syndrome and review of the literature.

ALG9-CDG is a CDG-I defect within the group of Congenital Disorders of Glycosylation (CDG). We here describe the clinical symptoms of two new and unrelated ALG9-CDG patients, both carrying the novel homozygous missense variant c.1460 T > C (p.L487P) in the ALG9 gene which led to global developmental delay, psychomotor disability, facial dysmorphisms, brain and heart defects, hearing loss, hypotonia, as well as feeding problems. New clinical symptoms comprised West syndrome with hypsarrhythmia. Quantitative RT-PCR analysis revealed a significantly enhanced ALG9 mRNA transcript level, whereas the protein amount in fibroblasts was significantly reduced. This could be ascribed to a stronger degradation of the mutated ALG9 protein in patient fibroblasts. Lipid-linked oligosaccharide analysis showed an ALG9-CDG characteristic accumulation of Man6GlcNAc2-PP-dolichol and Man8GlcNAc2-PP-dolichol in patient cells. The clinical findings of our patients and of all previously published ALG9-CDG patients are brought together to further expand the knowledge about this rare N-glycosylation disorder. SYNOPSIS: Homozygosity for p.L487P in ALG9 causes protein degradation and leads to West syndrome.

Autoantibodies against interleukin-1 receptor antagonist in multisystem inflammatory syndrome in children: a multicentre, retrospective, cohort study.

Background: Multisystem inflammatory syndrome in children (MIS-C) is a rare but serious complication of infection with SARS-CoV-2. A possible involvement of pathogenetically relevant autoantibodies has been discussed. Recently, neutralising autoantibodies against inflammatory receptor antagonists progranulin and interleukin-1 receptor antagonist (IL-1Ra) were found in adult patients with critical COVID-19. The aim of this study was to investigate the role of such autoantibodies in MIS-C. Methods: In this multicentre, retrospective, cohort study, plasma and serum samples were collected from patients (0-18 years) with MIS-C (as per WHO criteria) treated at five clinical centres in Germany and Spain. As controls, we included plasma or serum samples from children with Kawasaki disease, children with inactive systemic juvenile idiopathic arthritis, and children with suspected growth retardation (non-inflammatory control) across four clinical centres in Germany and Spain (all aged ≤18 years). Serum samples from the CoKiBa trial were used as two further control groups, from healthy children (negative for SARS-CoV-2 antibodies) and children with previous mild or asymptomatic COVID-19 (aged ≤17 years). MIS-C and control samples were analysed for autoantibodies against IL-1Ra and progranulin, and for IL-1Ra concentrations, by ELISA. Biochemical analysis of plasma IL-1Ra was performed with native Western blots and isoelectric focusing. Functional activity of the autoantibodies was examined by an in vitro IL-1ß-signalling reporter assay. Findings: Serum and plasma samples were collected between March 6, 2011, and June 2, 2021. Autoantibodies against IL-1Ra could be detected in 13 (62%) of 21 patients with MIS-C (11 girls and ten boys), but not in children with Kawasaki disease (n=24; nine girls and 15 boys), asymptomatic or mild COVID-19 (n=146; 72 girls and 74 boys), inactive systemic juvenile idiopathic arthritis (n=10; five girls and five boys), suspected growth retardation (n=33; 13 girls and 20 boys), or in healthy controls (n=462; 230 girls and 232 boys). Anti-IL-1Ra antibodies in patients with MIS-C belonged exclusively to the IgG1 subclass, except in one patient who had additional IL-1Ra-specific IgM antibodies. Autoantibodies against progranulin were only detected in one (5%) patient with MIS-C. In patients with MIS-C who were positive for anti-IL-1Ra antibodies, free plasma IL-1Ra concentrations were reduced, and immune-complexes of IL-1Ra were detected. Notably, an additional, hyperphosphorylated, transiently occurring atypical isoform of IL-1Ra was observed in all patients with MIS-C who were positive for anti-IL-1Ra antibodies. Anti-IL-1Ra antibodies impaired IL-1Ra function in reporter cell assays, resulting in amplified IL-1ß signalling. Interpretation: Anti-IL-1Ra autoantibodies were observed in a high proportion of patients with MIS-C and were specific to these patients. Generation of these autoantibodies might be triggered by an atypical, hyperphosphorylated isoform of IL-1Ra. These autoantibodies impair IL-1Ra bioactivity and might thus contribute to increased IL-1ß-signalling in MIS-C. Funding: NanoBioMed fund of the University of Saarland, José Carreras Center for Immuno and Gene Therapy, Dr Rolf M Schwiete Stiftung, Staatskanzlei Saarland, German Heart Foundation, Charity of the Blue Sisters, Bavarian Ministry of Health, the Center for Interdisciplinary Clinical Research at University Hospital Münster, EU Horizon 2020.

A novel pathogenic variant in MYO18B associating early-onset muscular hypotonia, and characteristic dysmorphic features, delineation of the phenotypic spectrum of MYO18B-related conditions.

Homozygous loss-of-function variants in MYO18B have been associated with congenital myopathy, facial dysmorphism and Klippel-Feil anomaly. So far, only four patients have been reported. Comprehensive description of new cases that help to highlight recurrent features and to further delineate the phenotypic spectrum are still missing. We present the fifth case of MYO18B-associated disease in a newborn male patient. Trio exome sequencing identified the previously unreported homozygous nonsense variant c.6433C>T, p.(Arg2145*) in MYO18B (NM_032608.5). While most phenotypic features of our patient align with previously reported cases, we describe the prenatal features for the first time. Taking the phenotypic description of our patient into account, we propose that the core phenotype comprises a severe congenital myopathy with feeding difficulties in infancy and characteristic dysmorphic features.

Biallelic variants in the transcription factor PAX7 are a new genetic cause of myopathy.

PURPOSE: Skeletal muscle growth and regeneration rely on muscle stem cells, called satellite cells. Specific transcription factors, particularly PAX7, are key regulators of the function of these cells. Knockout of this factor in mice leads to poor postnatal survival; however, the consequences of a lack of PAX7 in humans have not been established. METHODS: Here, we study five individuals with myopathy of variable severity from four unrelated consanguineous couples. Exome sequencing identified pathogenic variants in the PAX7 gene. Clinical examination, laboratory tests, and muscle biopsies were performed to characterize the disease. RESULTS: The disease was characterized by hypotonia, ptosis, muscular atrophy, scoliosis, and mildly dysmorphic facial features. The disease spectrum ranged from mild to severe and appears to be progressive. Muscle biopsies showed the presence of atrophic fibers and fibroadipose tissue replacement, with the absence of myofiber necrosis. A lack of PAX7 expression was associated with satellite cell pool exhaustion; however, the presence of residual myoblasts together with regenerating myofibers suggest that a population of PAX7-independent myogenic cells partially contributes to muscle regeneration. CONCLUSION: These findings show that biallelic variants in the master transcription factor PAX7 cause a new type of myopathy that specifically affects satellite cell survival.

High resolution transbulbar sonography in children with suspicion of increased intracranial pressure.

PURPOSE: To evaluate the accuracy of high resolution transbulbar sonography for the estimation of intracranial pressure (ICP) in children. METHODS: In children and adolescents with acute neurologic symptoms of various origin, transbulbar sonography was performed. Besides measurement of the optic nerve sheath diameter (ONSD), the ultrastructure of the subarachnoid space of the optic nerve sheath was evaluated. The results of transbulbar sonography were correlated with clinical data based on cross-sectional imaging, ICP measurement, and ophthalmologic examination. RESULTS: Eighty-one patients (age 3-17.8 years, mean 11.7 years) were included. In 25 children, cross-sectional imaging and ICP measurement revealed increased intracranial pressure. The mean ONSD was 6.85 ± 0.81 mm. Twenty patients (20/25, 80 %) had a microcystic appearance of the subarachnoid space of the optic nerve. In 56 children without evidence of increased intracranial pressure, the mean ONSD was 5.77 ± 0.48 mm. Forty-nine patients (49/56, 87.5 %) had a normal homogenous appearance of the subarachnoid space. The ONSD in children with increased intracranial pressure was significantly higher than in patients without (p < 0.001). CONCLUSION: High resolution transbulbar sonography of the optic nerve is a useful technique for the rapid and non-invasive estimation of intracranial pressure in children. Besides measurement of the optic nerve sheath diameter, evaluation of the ultrastructure of the subarachnoid space of the optic nerve is a helpful parameter.

Fast semi-automated lesion demarcation in stroke.

Lesion-behaviour mapping analyses require the demarcation of the brain lesion on each (usually transverse) slice of the individual stroke patient's brain image. To date, this is generally thought to be most precise when done manually, which is, however, both time-consuming and potentially observer-dependent. Fully automated lesion demarcation methods have been developed to address these issues, but these are often not practicable in acute stroke research where for each patient only a single image modality is available and the available image modality differs over patients. In the current study, we evaluated a semi-automated lesion demarcation approach, the so-called Clusterize algorithm, in acute stroke patients scanned in a range of common image modalities. Our results suggest that, compared to the standard of manual lesion demarcation, the semi-automated Clusterize algorithm is capable of significantly speeding up lesion demarcation in the most commonly used image modalities, without loss of either lesion demarcation precision or lesion demarcation reproducibility. For the three investigated acute datasets (CT, DWI, T2FLAIR), containing a total of 44 patient images obtained in a regular clinical setting at patient admission, the reduction in processing time was on average 17.8 min per patient and this advantage increased with increasing lesion volume (up to 60 min per patient for the largest lesion volumes in our datasets). Additionally, our results suggest that performance of the Clusterize algorithm in a chronic dataset with 11 T1 images was comparable to its performance in the acute datasets. We thus advocate the use of the Clusterize algorithm, integrated into a simple, freely available SPM toolbox, for the precise, reliable and fast preparation of imaging data for lesion-behaviour mapping analyses.

Microstructure of transcallosal motor fibers reflects type of cortical (re-)organization in congenital hemiparesis.

BACKGROUND: Early unilateral brain lesions can lead to different types of corticospinal (re-)organization of motor networks. In one group of patients, the contralesional hemisphere exerts motor control not only over the contralateral non-paretic hand but also over the (ipsilateral) paretic hand, as the primary motor cortex is (re-)organized in the contralesional hemisphere. Another group of patients with early unilateral lesions shows "normal" contralateral motor projections starting in the lesioned hemisphere. AIM: We investigated how these different patterns of cortical (re-)organization affect interhemispheric transcallosal connectivity in patients with congenital hemiparesis. METHOD: Eight patients with ipsilateral motor projections (group IPSI) versus 7 patients with contralateral motor projections (group CONTRA) underwent magnetic resonance diffusion tensor imaging (DTI). The corpus callosum (CC) was subdivided in 5 areas (I-V) in the mid-sagittal slice and volumetric information. The following diffusion parameters were calculated: fractional anisotropy (FA), trace, radial diffusivity (RD), and axial diffusivity (AD). RESULTS: DTI revealed significantly lower FA, increased trace and RD for group IPSI compared to group CONTRA in area III of the corpus callosum, where transcallosal motor fibers cross the CC. In the directly neighboring area IV, where transcallosal somatosensory fibers cross the CC, no differences were found for these DTI parameters between IPSI and CONTRA. Volume of callosal subsections showed significant differences for area II (connecting premotor cortices) and III, where group IPSI had lower volume. INTERPRETATION: The results of this study demonstrate that the callosal microstructure in patients with congenital hemiparesis reflects the type of cortical (re-)organization. Early lesions disrupting corticospinal motor projections to the paretic hand consecutively affect the development or maintenance of transcallosal motor fibers.

Two types of exercise-induced neuroplasticity in congenital hemiparesis: a transcranial magnetic stimulation, functional MRI, and magnetoencephalography study.

AIM: Early unilateral brain lesions can lead to a persistence of ipsilateral corticospinal projections from the contralesional hemisphere, which can enable the contralesional hemisphere to exert motor control over the paretic hand. In contrast to the primary motor representation (M1), the primary somatosensory representation (S1) of the paretic hand always remains in the lesioned hemisphere. Here, we report on differences in exercise-induced neuroplasticity between individuals with such ipsilateral motor projections (ipsi) and individuals with early unilateral lesions but 'healthy' contralateral motor projections (contra). METHOD: Sixteen children and young adults with congenital hemiparesis participated in the study (contralateral [Contra] group: n=7, four females, three males; age range 10-30y, median age 16y; ipsilateral [Ipsi] group: n=9, four females, five males; age range 11-31y, median age 12y; Manual Ability Classification System levels I to II in all individuals in both groups). The participants underwent a 12-day intervention of constraint-induced movement therapy (CIMT), consisting of individual training (2h/d) and group training (8h/d). Before and after CIMT, hand function was tested using the Wolf Motor Function Test (WMFT) and diverging neuroplastic effects were observed by transcranial magnetic stimulation (TMS), functional magnetic resonance imaging (fMRI), and magnetoencephalography (MEG). Statistical analysis of TMS data was performed using the non-parametric Wilcoxon signed-rank test for pair-wise comparison; for fMRI standard statistical parametric and non-parametric mapping (SPM5, SnPM3) procedures (first level/second level) were carried out. Statistical analyses of MEG data involved analyses of variance (ANOVA) and t-tests. RESULTS: While MEG demonstrated a significant increase in S1 activation in both groups (p=0.012), TMS showed a decrease in M1 excitability in the Ipsi group (p=0.036), but an increase in M1 excitability in the Contra group (p=0.043). Similarly, fMRI showed a decrease in M1 activation in the Ipsi group, but an increase in activation in the M1-S1 region in the Contra group (for both groups p<0.001 [SnPM3] within the search volume). INTERPRETATION: Different patterns of sensorimotor (re)organization in individuals with early unilateral lesions show, on a cortical level, different patterns of exercise-induced neuroplasticity. The findings help to improve the understanding of the general principles of sensorimotor learning and will help to develop more specific therapies for different pathologies in congenital hemiparesis.

(18) F-fluorodeoxyglucose positron emission tomography/computed tomography for the detection of recurrent bone and soft tissue sarcoma.

BACKGROUND: The clinical utility of modern hybrid imaging modalities for detecting recurrent bone or soft tissue sarcoma remains to be determined. In this report, the authors present a clinical study on the diagnostic accuracy and incremental value of integrated (18) F-fluorodeoxyglucose positron emission tomography/computed tomography ((18) F-FDG PET/CT) in patients with a history of sarcoma who have clinically suspected disease recurrence. METHODS: Forty-three patients who had a history of bone or soft tissue sarcoma and had documented complete remission underwent (18) F-FDG PET/CT. Image analysis was performed independently for (18) F-FDG PET (n = 43) and for contrast-enhanced spiral CT (CE-CT) (n = 30) by 2 separate readers, whereas combined (18) F-FDG PET/CT (n = 43) images were analyzed in consensus by both readers. Imaging findings were rated on a 5-point scale and finally were reported as malignant, benign, or equivocal. Imaging findings were validated either by histopathology (n = 24) or by clinical follow-up (n = 19). RESULTS: (18) F-FDG PET/CT had greater sensitivity and specificity compared with CE-CT alone (94% and 92% vs 78% and 67%, respectively), resulting in significantly greater accuracy (93% vs 73%; P = .03). (18) F-FDG PET/CT was particularly superior regarding detection of local recurrence or soft tissue lesions (sensitivity and specificity: 83% and 100% vs 50% and 100%, respectively) or bone metastases (100% and 100% vs 85% and 88%, respectively). CONCLUSIONS: (18) F-FDG PET/CT had greater diagnostic accuracy in the detection of recurrent bone or soft tissue sarcoma compared with CE-CT alone. The detection of local recurrence was the most evident advantage of (18) F-FDG PET/CT over CE-CT. Cancer 2013. © 2012 American Cancer Society.

Manual, semi-automated, and automated delineation of chronic brain lesions: a comparison of methods.

The exact delineation of chronic brain lesions is a crucial step when investigating the relationship between brain structure and (dys-)function. For this, manual tracing, although very time-consuming, is still the gold standard. In order to assess the possible contributions from other methods, we compared manual tracing of lesion boundaries with a newly developed semi-automated and a fully automated approach for lesion definition in a sample of chronic stroke patients (n=11, 5m, median age 12, range 10-30years). Manual tracing requires substantially more human input (4.8-9.6h/subject) than semi-automated (24.9min/subject) and automated processing (1min/subject). When compared with manual tracing as the gold standard, both the semi-automated (tested with 4 different smoothing filters) and the automated approach towards lesion definition performed on an acceptable level, with an average Dice's similarity index of .53-.60 (semi-automated) and .49 (automated processing). In all semi-automated and automated approaches, larger lesions were identified with a significantly higher performance than smaller lesions, as were central versus peripheral voxels, indicating that the surface-to-volume ratio explains this trend. The automated approach failed to identify two lesions. In several cases, indirect lesion effects (such as enlarged ventricles) were detected using the semi-automated or the automated approach. We conclude that manual tracing remains the gold standard for exact lesion delineation, but that semi-automated and automated approaches may be alternatives for larger lesions and/or larger studies. The detection of indirect lesion effects may be another application of such approaches in the future.

Early determination of somatosensory cortex in the human brain.

The developing brain possesses a high potential for neuroplasticity. Yet, this remarkable potential of (re-)organization is not a general principle. It seems to vary among different functional systems. Here, we show that distinct brain structures involved in somatosensory processing are already prenatally determined so that a pre- or perinatally acquired (congenital) brain damage of such structures results in a persistent somatosensory deficit. Eleven patients with hemiparesis due to congenital cortico-subcortical unilateral stroke who showed versus not showed a somatosensory deficit were contrasted with magnetic resonance imaging lesion-behavior mapping. The brain areas which were typically damaged in patients with a somatosensory deficit but typically spared in patients without a somatosensory deficit were located in the primary and secondary somatosensory cortex (S1, S2) as well as the inferior parietal cortex directly neighboring S1 and S2. The results argue for an early functional determination of primary and secondary somatosensory cortex, without substantial capacities for (re-)organization. They demonstrate that cortical damage of these areas cannot be compensated by shifting the functional representation to undamaged parts of the cortex.

Misleading functional magnetic resonance imaging mapping of the cortical hand representation in a 4-year-old boy with an arteriovenous malformation of the central region.

Functional MR imaging is dependent on the hemodynamic response function of the brain. Cerebrovascular anomalies may lead to hemodynamic artifacts, contorting the true localization of neural activation. This is illustrated in the case of a 4-year-old boy with an arteriovenous malformation (AVM) of the left central region undergoing extensive functional mapping prior to surgical removal. Intraoperative electrophysiological recording confirmed presurgical results of magnetoencephalography (MEG) and transcranial magnetic stimulation (TMS) examinations, detecting the sensorimotor hand representation within the brain tissue into which the AVM extended, whereas the activation demonstrated by functional MR (fMR) imaging was proven to be falsely localized by that modality, which showed it to be posterior to the affected central region. Thus, this case demonstrates that functional mapping can be performed even in very young patients and that combining fMR imaging with TMS and MEG is especially important in patients with vascular lesions, in whom fMR imaging can be misleading due to changes in blood flow.

Motor cortex plasticity in ischemic perinatal stroke: a transcranial magnetic stimulation and functional MRI study.

To assess motor cortex plasticity after constraint-induced movement therapy in patients with ischemic perinatal stroke, functional MRI and transcranial magnetic stimulation were applied. Seven hemiparetic patients with ischemic perinatal stroke of the middle cerebral artery and preserved crossed corticospinal projections to the paretic hand were studied before and after 12 days of constraint-induced movement therapy. After therapy, all patients demonstrated improved manual motor function. Transcranial magnetic stimulation of the motor cortex of the affected hemisphere revealed a significant increase of motor-evoked potential amplitude recorded from the paretic hand, whereas no significant change was detected in the nonparetic hand after transcranial magnetic stimulation of the contralesional hemisphere. Functional MRI revealed increased activation of the contralateral central region (including primary sensorimotor cortex) and supplementary motor area during active movement of the paretic hand. No change in functional MRI activation was detected during passive movement of the paretic hand or during active and passive movement of the nonparetic hand. In ischemic perinatal stroke with crossed corticospinal projections, constraint-induced movement therapy induces neuroplastic changes on the synaptic level, detected as increased excitability (transcranial magnetic stimulation) and increased task-related brain activation (functional MRI) in the primary motor cortex of the lesioned hemisphere.

Somatosensory system in two types of motor reorganization in congenital hemiparesis: topography and function.

This study investigates the (re-)organization of somatosensory functions following early brain lesions. Using functional magnetic resonance imaging (fMRI), passive hand movement was studied. Transcranial magnetic stimulation (TMS) and magnetoencephalography (MEG) were used as complementary methods. fMRI data was analyzed on the first level with regard to topographical variability; second-level group effects as well as the overall integrity of the somatosensory circuitry were also assessed. Subjects with unilateral brain lesions occurring in the third trimester of pregnancy or perinatally with different types of motor reorganization were included: patients with regular, contralateral motor organization following middle cerebral artery strokes (CONTRA(MCA), n = 6) and patients with reorganized, ipsilateral motor functions due to periventricular lesions (IPSI(PL), n = 8). Motor impairment was similar, but sensory impairment was more pronounced in the CONTRA(MCA) group. Using fMRI and MEG, both groups showed a normal pattern with a contralateral somatosensory representation, despite the transhemispherically reorganized primary motor cortex in the IPSI(PL) group, as verified by TMS. Activation topography for the paretic hands was more variable than for the nonparetic hand in both groups. The cortico-cerebellar circuitry was well-preserved in almost all subjects. We conclude that in both models of motor reorganization, no interhemispheric reorganization of somatosensory functions occurred. Also, no relevant intrahemispheric reorganization was observed apart from a higher topographical variability of fMRI activations. This preserved pattern of somatosensory organization argues in favor of a differential lesion effect on motor and somatosensory functions and demonstrates a limited compensatory potential for the latter.

Abnormal motor cortex excitability in congenital stroke.

The aim of the present study was to investigate corticospinal and intracortical excitability in patients with congenital stroke. In adults, stroke sequelae reduce corticospinal excitability, as indicated by an elevated threshold for motor evoked potentials (MEP), and increase intracortical excitability, as indicated by reduced intracortical inhibition. Ten patients with pre- or perinatally acquired, unilateral cortico-subcortical infarctions in the middle cerebral artery territory were studied with single pulse transcranial magnetic stimulation (TMS) to measure motor threshold (MT) and with paired pulse TMS to study short interval intracortical inhibition (SICI) and intracortical facilitation (ICF). Eight healthy, age-matched subjects served as controls. MT over the affected hemisphere of patients compared with the dominant hemisphere of controls was significantly elevated, reflecting reduced corticospinal excitability, and SICI was significantly reduced, reflecting increased intracortical excitability. No such differences were found for ICF. Findings in patients with congenital stroke were comparable with adulthood stroke. Thus, similar assumptions can be made: reduced corticospinal excitability is probably a consequence of neuronal damage. Reduced intracortical inhibition might represent deficient inhibitory cortical properties or might reflect a compensational mechanism, dispositioning for use-dependent plasticity.

Tetraspanin-5 (Tm4sf9) mRNA expression parallels neuronal maturation in the cerebellum of normal and L7En-2 transgenic mice.

Tetraspanin-5 (Tspan-5) mRNA was recently shown to be strongly expressed within the central nervous system. In order to address Tspan-5 function during nervous system development, we performed a detailed expression analysis in the postnatal FVB/N mouse cerebellum using in situ hybridizations. Tspan-5 mRNA was expressed within cerebellar Purkinje cells (PCs) throughout postnatal development. The expression level, however, changed significantly with ongoing development. At the day of birth (P0), Tspan-5 mRNA was expressed at very low levels in PCs. At this time, PCs of the FVB/N strain are postmitotic and bear axons, but no dendrites. At P7, Tspan-5 mRNA expression was visible in all PCs, but was more prominent in those of the posterior lobules as compared to those of the anterior lobules. After P7, high levels of Tspan-5 mRNA were seen in all PCs, which is when PCs elaborate and maintain their typical dendritic tree. This demonstrates that the level of Tspan-5 mRNA is related to the developmental status of PCs. Consistently, expression of Tspan-5 mRNA was specifically reduced in PCs of L7En-2 animals, which display a delay in PC maturation during postnatal cerebellar development. In addition, whereas no Tspan-5 mRNA signal could be detected in the proliferating granule cell layer, low levels could be found in postmitotic, premigratory granule cells and high levels in settled and differentiated granule cells. Thus, the level of Tspan-5 mRNA expression correlates very well with the differentiation status of particular neurons. The level of Tspan-5 expression might therefore be important for distinct phases of neuronal maturation.