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Resumen Introduccion El sindrome opsoclono-mioclono-ataxia es un raro trastorno de inicio pediatrico; de base neuroinflamatoria y origen paraneoplasico, parainfeccioso o idiopatico. Actualmente no hay biomarcadores, siendo el diagnostico clinico. El pronostico cognitivo parece estar relacionado con el inicio temprano de la terapia inmunomoduladora. Metodo Se describen las caracteristicas epidemiologicas, clinicas, terapeuticas y pronosticas a largo plazo de una cohorte de 20 pacientes espanoles. Resultados La edad media de debut fue de 21 meses (2-59 meses). La ataxia y el opsoclonus fueron los sintomas de inicio mas frecuentes y predominantes en la evolucion. El tiempo medio desde los primeros sintomas hasta el diagnostico fue de 1,1 mes. Un tumor de extirpe neuroblastica fue detectado en el 45%, realizandose reseccion quirurgica en siete y quimioterapia en dos pacientes. En el estudio de liquido cefalorraquideo se constato pleocitosis en cuatro (25%), con negatividad de anticuerpos antineuronales y bandas oligoclonales en todos los casos estudiados. En el 100% se emplearon farmacos inmunomoduladores. En nueve pacientes el tratamiento combinado inmunomodulador se inicio desde el momento del diagnostico, y en cinco el tiempo medio de implementacion fue de 2,2 meses. A largo plazo, seis de 10 pacientes con seguimiento superior a cinco anos presentaban secuelas cognitivas leves o moderadas; cuatro pacientes presentaron recaidas, generalmente coincidiendo con el descenso de la corticoterapia. Conclusiones El inicio precoz de la inmunoterapia, asi como de la triple terapia en los casos que lo precisaron, se relaciono con una menor frecuencia de afectacion cognitiva a los dos anos del debut.

Glucose transporter 1 deficiency syndrome (GLUT1DS) is a neurometabolic disorder caused by haploinsufficiency of the GLUT1 glucose transporter (encoded by SLC2A1) leading to defective glucose transport across the blood–brain barrier. This work describes the genetic analysis of 56 patients with clinical or biochemical GLUT1DS hallmarks. 55.4% of these patients had a pathogenic variant of SLC2A1, and 23.2% had a variant in one of 13 different genes. No pathogenic variant was identified for the remaining patients. Expression analysis of SLC2A1 indicated a reduction in SLC2A1 mRNA in patients with pathogenic variants of this gene, as well as in one patient with a pathogenic variant in SLC9A6, and in three for whom no candidate variant was identified. Thus, the clinical and biochemical hallmarks generally associated with GLUT1DS may be caused by defects in genes other than SLC2A1, Carlos III Institute (ISCIII), European Regional Development Funds (PI19/01155); CIBERER (ERTRLE0I1); Consejería de Educacion, Juventud y Deporte, Comunidad de Madrid (B2017/BMD3721); Fundacion Isabel Gemio, the Fundacion La Caixa (LCF/PR/ PR16/11110018)

Objective The absence of specific markers can make the diagnosis of neuroimmune disorders difficult, making other biomarkers such as thyroid peroxidase antibodies (TPO-Abs) more relevant. Laboratory tests are susceptible to interference, especially those tests performed using immunoassay techniques. The effect of treatment with human intravenous immunoglobulin (IVIG) on the results of TPO-Abs assays has not been previously characterized. Materials and Methods We analyzed TPO-Abs levels in 170 children monitored in the neuroimmune disease department of a tertiary hospital. We analyzed the characteristics of patients with increased TPO-Abs values and compared their progress with and without treatment. Results We found that 97% of patients with elevated TPO-Abs had received IVIG. After withdrawal from IVIG, a mean TPO-Abs decrease of 62.5% at 1 month was observed. The IVIG drug preparation was found to contain 1176 U/mL of TPO-Abs. An interferogram confirmed interference. Conclusion It is advisable to measure levels of TPO-Abs before starting immunotherapy and remain vigilant regarding possible interference in the event of unsubstantiated elevations of this analyte.

BackgroundRNA polymerase III-related or 4H leukodystrophy (POLR3-HLD) is an autosomal recessive hypomyelinating leukodystrophy characterized by neurological dysfunction, hypodontia and hypogonadotropic hypogonadism. The disease is caused by biallelic pathogenic variants inPOLR3A,POLR3B,POLR1CorPOLR3K. Craniofacial abnormalities reminiscent of Treacher Collins syndrome have been originally described in patients with POLR3-HLD caused by biallelic pathogenic variants inPOLR1C. To date, no published studies have appraised in detail the craniofacial features of patients with POLR3-HLD. In this work, the specific craniofacial characteristics of patients with POLR3-HLD associated with biallelic pathogenic variants inPOLR3A,POLR3BandPOLR1Care described.MethodsThe craniofacial features of 31 patients with POLR3-HLD were evaluated, and potential genotype–phenotype associations were evaluated.ResultsVarious craniofacial abnormalities were recognized in this patient cohort, with each individual presenting at least one craniofacial abnormality. The most frequently identified features included a flat midface (61.3%), a smooth philtrum (58.0%) and a pointed chin (51.6%). In patients withPOLR3Bbiallelic variants, a thin upper lip was frequent. Craniofacial anomalies involving the forehead were most commonly associated with biallelic variants inPOLR3AandPOLR3Bwhile a higher proportion of patients withPOLR1Cbiallelic variants demonstrated bitemporal narrowing.ConclusionThrough this study, we demonstrated that craniofacial abnormalities are common in patients with POLR3-HLD. This report describes in detail the dysmorphic features of POLR3-HLD associated with biallelic variants inPOLR3A,POLR3BandPOLR1C.

Two-thirds of patients with mucopolysaccharidosis II (MPS II; Hunter syndrome) have cognitive impairment. This phase 2/3, randomized, controlled, open-label, multicenter study (NCT02055118) investigated the effects of intrathecally administered idursulfase-IT on cognitive function in patients with MPS II. Children older than 3 years with MPS II and mild-to-moderate cognitive impairment (assessed by Differential Ability Scales-II [DAS-II], General Conceptual Ability [GCA] score) who had tolerated intravenous idursulfase for at least 4 months were randomly assigned (2:1) to monthly idursulfase-IT 10 mg (n = 34) via an intrathecal drug delivery device (IDDD; or by lumbar puncture) or no idursulfase-IT treatment (n = 15) for 52 weeks. All patients continued to receive weekly intravenous idursulfase 0.5 mg/kg as standard of care. Of 49 randomized patients, 47 completed the study (two patients receiving idursulfase-IT discontinued). The primary endpoint (change from baseline in DAS-II GCA score at week 52 in a linear mixed-effects model for repeated measures analysis) was not met: although there was a smaller decrease in DAS-II GCA scores with idursulfase-IT than with no idursulfase-IT at week 52, this was not significant (least-squares mean treatment difference [95% confidence interval], 3.0 [-7.3, 13.3]; p = 0.5669). Changes from baseline in Vineland Adaptive Behavioral Scales-II Adaptive Behavior Composite scores at week 52 (key secondary endpoint) were similar in the idursulfase-IT (n = 31) and no idursulfase-IT (n = 14) groups. There were trends towards a potential positive effect of idursulfase-IT across DAS-II composite, cluster, and subtest scores, notably in patients younger than 6 years at baseline. In a post hoc analysis, there was a significant (p = 0.0174), clinically meaningful difference in change from baseline in DAS-II GCA scores at week 52 with idursulfase-IT (n = 13) versus no idursulfase-IT (n = 6) among those younger than 6 years with missense iduronate-2-sulfatase gene variants. Overall, idursulfase-IT reduced cerebrospinal glycosaminoglycan levels from baseline by 72.0% at week 52. Idursulfase-IT was generally well tolerated. These data suggest potential benefits of idursulfase-IT in the treatment of cognitive impairment in some patients with neuronopathic MPS II. After many years of extensive review and regulatory discussions, the data were found to be insufficient to meet the evidentiary standard to support regulatory filings.

Enzyme replacement therapy with weekly infused intravenous (IV) idursulfase is effective in treating somatic symptoms of mucopolysaccharidosis II (MPS II; Hunter syndrome). A formulation of idursulfase for intrathecal administration (idursulfase-IT) is under investigation for the treatment of neuronopathic MPS II. Here, we report 36-month data from the open-label extension (NCT02412787) of a phase 2/3, randomized, controlled study (HGT-HIT-094; NCT02055118) that assessed the safety and efficacy of monthly idursulfase-IT 10 mg in addition to weekly IV idursulfase on cognitive function in children older than 3 years with MPS II and mild-to-moderate cognitive impairment. Participants were also enrolled in this extension from a linked non-randomized sub-study of children younger than 3 years at the start of idursulfase-IT therapy. The extension safety population comprised 56 patients who received idursulfase-IT 10 mg once a month (or age-adjusted dose for sub-study patients) plus IV idursulfase (0.5 mg/kg) once a week. Idursulfase-IT was generally well tolerated over the cumulative treatment period of up to 36 months. Overall, 25.0% of patients had at least one adverse event (AE) related to idursulfase-IT; most treatment-emergent AEs were mild in severity. Of serious AEs (reported by 76.8% patients), none were considered related to idursulfase-IT treatment. There were no deaths or discontinuations owing to AEs. Secondary efficacy analyses (in patients younger than 6 years at phase 2/3 study baseline; n = 40) indicated a trend for improved Differential Ability Scale-II (DAS-II) General Conceptual Ability (GCA) scores in the early idursulfase-IT versus delayed idursulfase-IT group (treatment difference over 36 months from phase 2/3 study baseline: least-squares mean, 6.8 [90% confidence interval: -2.1, 15.8; p = 0.2064]). Post hoc analyses of DAS-II GCA scores by genotype revealed a clinically meaningful treatment effect in patients younger than 6 years with missense variants of the iduronate-2-sulfatase gene (IDS) (least-squares mean [standard error] treatment difference over 36 months, 12.3 [7.24]). These long-term data further suggest the benefits of idursulfase-IT in the treatment of neurocognitive dysfunction in some patients with MPS II. After many years of extensive review and regulatory discussions, the data were found to be insufficient to meet the evidentiary standard to support regulatory filings.

Objective: Phosphomannomutase deficiency (PMM2 congenital disorder of glycosylation [PMM2-CDG]) causes cerebellar syndrome and strokelike episodes (SLEs). SLEs are also described in patients with gain-of-function mutations in the CaV2.1 channel, for which acetazolamide therapy is suggested. Impairment in N-glycosylation of CaV2.1 promotes gain-of-function effects and may participate in cerebellar syndrome in PMM2-CDG. AZATAX was designed to establish whether acetazolamide is safe and improves cerebellar syndrome in PMM2-CDG. Methods: A clinical trial included PMM2-CDG patients, with a 6-month first-phase single acetazolamide therapy group, followed by a randomized 5-week withdrawal phase. Safety was assessed. The primary outcome measure was improvement in the International Cooperative Ataxia Rating Scale (ICARS). Other measures were the Nijmegen Pediatric CDG Rating Scale (NPCRS), a syllable repetition test (PATA test), and cognitive scores. Results: Twenty-four patients (mean age = 12.3 ± 4.5 years) were included, showing no serious adverse events. Thirteen patients required dose adjustment due to low bicarbonate or asthenia. There were improvements on ICARS (34.9 ± 23.2 vs 40.7 ± 24.8, effect size = 1.48, 95% confidence interval [CI] = 4.0–7.6, p < 0.001), detected at 6 weeks in 18 patients among the 20 responders, on NPCRS (95% CI = 0.3–1.6, p = 0.013) and on the PATA test (95% CI = 0.5–3.0, p = 0.006). Acetazolamide improved prothrombin time, factor X, and antithrombin. Clinical severity, epilepsy, and lipodystrophy predicted greater response. The randomized withdrawal phase showed ICARS worsening in the withdrawal group (effect size = 1.46, 95% CI = 2.65–7.52, p = 0.001). Interpretation: AZATAX is the first clinical trial of PMM2-CDG. Acetazolamide is well tolerated and effective for motor cerebellar syndrome. Its ability to prevent SLEs and its long-term effects on kidney function should be addressed in future studies. Ann Neurol 2019;85:740–751.

The neurological phenotype of 3-hydroxyisobutyryl-CoA hydrolase (HIBCH) and short-chain enoyl-CoA hydratase (SCEH) defects is expanding and natural history studies are necessary to improve clinical management. From 42 patients with Leigh syndrome studied by massive parallel sequencing, we identified five patients with SCEH and HIBCH deficiency. Fourteen additional patients were recruited through collaborations with other centres. In total, we analysed the neurological features and mutation spectrum in 19 new SCEH/HIBCH patients. For natural history studies and phenotype to genotype associations we also included 70 previously reported patients. The 19 newly identified cases presented with Leigh syndrome (SCEH, n = 11; HIBCH, n = 6) and paroxysmal dystonia (SCEH, n = 2). Basal ganglia lesions (18 patients) were associated with small cysts in the putamen/pallidum in half of the cases, a characteristic hallmark for diagnosis. Eighteen pathogenic variants were identified, 11 were novel. Among all 89 cases, we observed a longer survival in HIBCH compared to SCEH patients, and in HIBCH patients carrying homozygous mutations on the protein surface compared to those with variants inside/near the catalytic region. The SCEH p.(Ala173Val) change was associated with a milder form of paroxysmal dystonia triggered by increased energy demands. In a child harbouring SCEH p.(Ala173Val) and the novel p.(Leu123Phe) change, an 83.6% reduction of the protein was observed in fibroblasts. The SCEH and HIBCH defects in the catabolic valine pathway were a frequent cause of Leigh syndrome in our cohort. We identified phenotype and genotype associations that may help predict outcome and improve clinical management.

Phosphoinositides are lipids that play a critical role in processes such as cellular signalling, ion channel activity and membrane trafficking. When mutated, several genes that encode proteins that participate in the metabolism of these lipids give rise to neurological or developmental phenotypes. PI4KA is a phosphoinositide kinase that is highly expressed in the brain and is essential for life. Here we used whole exome or genome sequencing to identify 10 unrelated patients harbouring biallelic variants in PI4KA that caused a spectrum of conditions ranging from severe global neurodevelopmental delay with hypomyelination and developmental brain abnormalities to pure spastic paraplegia. Some patients presented immunological deficits or genito-urinary abnormalities. Functional analyses by western blotting and immunofluorescence showed decreased PI4KA levels in the patients’ fibroblasts. Immunofluorescence and targeted lipidomics indicated that PI4KA activity was diminished in fibroblasts and peripheral blood mononuclear cells. In conclusion, we report a novel severe metabolic disorder caused by PI4KA malfunction, highlighting the importance of phosphoinositide signalling in human brain development and the myelin sheath., Verdura et al. report a novel rare brain metabolic disorder caused by recessive mutations in PI4KA, which encodes an enzyme with a pivotal role in phosphoinositide metabolism at the cell membrane. The description of this syndrome will simplify the identification of undiagnosed cases with similar clinical features.

The neurological phenotype of 3-hydroxyisobutyryl-CoA hydrolase (HIBCH) and short-chain enoyl-CoA hydratase (SCEH) defects is expanding and natural history studies are necessary to improve clinical management. From 42 patients with Leigh syndrome studied by massive parallel sequencing, we identified five patients with SCEH and HIBCH deficiency. Fourteen additional patients were recruited through collaborations with other centres. In total, we analysed the neurological features and mutation spectrum in 19 new SCEH/HIBCH patients. For natural history studies and phenotype to genotype associations we also included 70 previously reported patients. The 19 newly identified cases presented with Leigh syndrome (SCEH, n = 11; HIBCH, n = 6) and paroxysmal dystonia (SCEH, n = 2). Basal ganglia lesions (18 patients) were associated with small cysts in the putamen/pallidum in half of the cases, a characteristic hallmark for diagnosis. Eighteen pathogenic variants were identified, 11 were novel. Among all 89 cases, we observed a longer survival in HIBCH compared to SCEH patients, and in HIBCH patients carrying homozygous mutations on the protein surface compared to those with variants inside/near the catalytic region. The SCEH p.(Ala173Val) change was associated with a milder form of paroxysmal dystonia triggered by increased energy demands. In a child harbouring SCEH p.(Ala173Val) and the novel p.(Leu123Phe) change, an 83.6% reduction of the protein was observed in fibroblasts. The SCEH and HIBCH defects in the catabolic valine pathway were a frequent cause of Leigh syndrome in our cohort. We identified phenotype and genotype associations that may help predict outcome and improve clinical management.

Niemann–Pick type C (NP-C) disease is a neurovisceral atypical lysosomal lipid storage disorder with a poor prognosis. We present the 5-year neuropsychological follow-up of a patient with juvenile onset NP-C, spanning the pre-diagnostic stage to the period after treatment with miglustat (Actelion Pharmaceuticals Inc., CA, US). In the initial stages of the disease, the patient presented behavioral dysexecutive symptoms resembling those frequently observed in adult-onset forms and frontotemporal dementia, which frequently makes early diagnosis difficult in children. After 4 years of treatment, the impaired cognitive function and behavioral dysexecutive syndrome had been completely reversed. The variability of NP-C disease makes early diagnosis challenging. Evaluations of long-term neuropsychological development can help diagnose this neurodegenerative disease and document its progression.

Phosphomannomutase deficiency (PMM2-CDG) causes a cerebellar syndrome that has been evaluated using the International Cooperative Ataxia Rating Scale (ICARS). However, no particular dysarthria tests have been used. Speech ICARS subscore subjectively assesses fluency and clarity of speech with two items. Repetition of syllables, traditionally used for characterization of ataxic speech, was validated in early-onset ataxia conditions. We assess the validity of the PATA test (SCA Functional Index [SCAFI]) in PMM2-CDG patients.PATA rates from 20 patients were compared with a control population were and correlated with ICARS and neuroimaging.There was a difference between the PATA rate in patients and controls. PATA rate increased with age in controls. In patients, the improvement of PATA rate with age was not significant. In patients, the PATA rate was negatively correlated with the total ICARS score and the Speech ICARS subscore. Regarding neuroimaging, midsaggital vermis relative diameter was positively correlated with PATA results. These last differences were also significant when the results are corrected by age.PATA rate provides an easy measure for a quantitative assessment of dysarthria that may help clinicians to monitor patients' evolution in a regular consultation. It could also be used in PMM2-CDG clinical trials implementing ICARS speech subscore information.

Background: Mutations in the GRIN2A gene, which encodes the GluN2A (glutamate [NMDA] receptor subunit epsilon-1) subunit of the N-methyl-d-aspartate receptor, have been identified in patients with epilepsy-aphasia spectrum disorders, idiopathic focal epilepsies with centrotemporal spikes, and epileptic encephalopathies with severe developmental delay. However, thus far, mutations in this gene have not been associated with a nonepileptic neurodevelopmental disorder with dystonia. Objectives: The objective of this study was to identify the disease-causing gene in 2 siblings with neurodevelopmental and movement disorders with no epileptiform abnormalities. Methods: The study method was targeted next-generation sequencing panel for neuropediatric disorders and subsequent electrophysiological studies. Results: The 2 siblings carry a novel missense mutation in the GRIN2A gene (p.Ala643Asp) that was not detected in genomic DNA isolated from blood cells of their parents, suggesting that the mutation is the consequence of germinal mosaicism in 1 progenitor. In functional studies, the GluN2A-A643D mutation increased the potency of the agonists L-glutamate and glycine and decreased the potency of endogenous negative modulators, including protons, magnesium and zinc but reduced agonist-evoked peak current response in mammalian cells, suggesting that this mutation has a mixed effect on N-methyl-d-aspartate receptor function. Conclusion: De novo GRIN2A mutations can give rise to a neurodevelopmental and movement disorder without epilepsy. © 2018 International Parkinson and Movement Disorder Society.

Mucopolysaccharidosis are multisystem diseases that require large multidisciplinary teams for their care. Specific recommendations are therefore needed for the transition from childhood to adulthood in this patient group. To overcome the barriers that might arise during the transition, the authors consider it essential to implement a flexible plan with a coordinator for the entire process, systematising the information through a standardised paediatric discharge report and educating the patient and their family about the disease, showing the characteristics of the healthcare system in this new stage. The final objective is that, once the transition to adulthood has been completed, the patient's autonomy and potential development are maximised and that the patient receives appropriate healthcare during this transition.

Mucopolysaccharidosis are multisystem diseases that require large multidisciplinary teams for their care. Specific recommendations are therefore needed for the transition from childhood to adulthood in this patient group. To overcome the barriers that might arise during the transition, the authors consider it essential to implement a flexible plan with a coordinator for the entire process, systematizing the information through a standardized pediatric discharge report and educating the patient and their family about the disease, showing the characteristics of the healthcare system in this new stage. The final objective is that, once the transition to adulthood has been completed, the patient's autonomy and potential development are maximized and that the patient receives appropriate healthcare during this transition.

Background CAPOS syndrome (cerebellar ataxia, areflexia, pes cavus, optic atrophy, and sensorineural hearing loss) is a rare disease that has been reported in 22 patients so far. In all cases, the mutation c.2452G>A (p.Glu818Lys) in the ATP1A3 gene was identified. Patients typically present at an early age with an acute-onset fever-induced episode of ataxia frequently associated with encephalopathy and weakness. They usually present one to three episodes. The acute symptoms improve within days, but most patients show slow progression afterward. Methods We describe three new patients, a woman and her two sons diagnosed with CAPOS syndrome. A systematic review of literature on previously reported patients was performed. Results The first son presented with acute-onset ataxia, encephalopathy, and sensorineural hearing loss, induced by febrile illness. The second one developed generalized areflexia and mild instability without an acute episode. The mother had been previously diagnosed with sensorineural hearing loss and optic nerve atrophy. The c.2452G>A mutation in ATP1A3 was found in all three patients. Conclusion Only 25 Individuals with CAPOS syndrome have been reported, including our family. This is the first time a Spanish family has been described. The fact that both siblings were assessed before the first acute-onset episode contributes to the description of early symptoms and signs of the disease, which could aid early diagnosis and management before the onset of acute episodes.

BACKGROUND: Investigations of myelin oligodendrocyte glycoprotein (MOG) antibodies are usually focused on demyelinating syndromes, but the entire spectrum of MOG antibody-associated syndromes in children is unknown. In this study, we aimed to determine the frequency and distribution of paediatric demyelinating and encephalitic syndromes with MOG antibodies, their response to treatment, and the phenotypes associated with poor prognosis. METHODS: In this prospective observational study, children with demyelinating syndromes and with encephalitis other than acute disseminated encephalomyelitis (ADEM) recruited from 40 secondary and tertiary centres in Spain were investigated for MOG antibodies. All MOG antibody-positive cases were included in our study, which assessed syndromes, treatment and response to treatment (ie, number of relapses), outcomes (measured with the modified Rankin scale [mRS]), and phenotypes associated with poor prognosis. We used Fisher's exact and Wilcoxon rank sum tests to analyse clinical features, and survival Cox regression to analyse time to antibody negativity. FINDINGS: Between June 1, 2013, and Dec 31, 2018, 239 children with demyelinating syndromes (cohort A) and 296 with encephalitis other than ADEM (cohort B) were recruited. 116 patients had MOG antibodies, including 94 (39%) from cohort A and 22 (7%) from cohort B; 57 (49%) were female, with a median age of 6·2 years (IQR 3·7-10·0). Presenting syndromes in these 116 patients included ADEM (46 [68%]), encephalitis other than ADEM (22 [19%]), optic neuritis (20 [17%]), myelitis (13 [11%]), neuromyelitis optica spectrum disorders (six [5%]), and other disorders (nine [8%]). Among the patients with autoimmune encephalitis in cohort B (n=64), MOG antibodies were more common than all neuronal antibodies combined (22 [34%] vs 21 [33%]). After a median follow-up of 42 months (IQR 22-67), 33 (28%) of the 116 patients had relapses, including 17 (17%) of 100 diagnosed at first episode. Steroids, intravenous immunoglobulin, or plasma exchange were used in 100 (86%) patients at diagnosis, and 32 (97%) of 33 at relapses. Rituximab was mainly used at relapses (11 [33%]). 99 (85%) of 116 patients had substantial recovery (mRS 2; one died). Phenotypes of poor prognosis included ADEM-like relapses progressing to leukodystrophy-like features, and extensive cortical encephalitis evolving to atrophy. Time to antibody negativity was longer in patients with relapses (HR 0·18, 95% CI 0·05-0·59). INTERPRETATION: The spectrum of paediatric MOG antibody-associated syndromes is wider than previously reported and includes demyelinating syndromes and encephalitis. Recognition of these disorders has important clinical and prognostic implications. FUNDING: Mutua Madrileña Foundation; ISCIII-Subdirección General de Evaluación y Fomento de la Investigación Sanitaria; Fondo Europeo de Desarrollo Regional; Pediatrics Spanish Society; Departament de Salut, Generalitat de Catalunya; Marato TV3 Foundation; Red Española de Esclerosis Múltiple; La Caixa Foundation; and Fundació CELLEX.

Complex I (nicotinamide adenine dinucleotide (NADH): ubiquinone oxidoreductase) is the largest complex of the mitochondrial oxidative phosphorylation system (OXPHOS) system. Forty-four subunits encoded in nuclear and mitochondrial genomes compose this multiprotein complex, its assembly being a highly complex process involving at least 15 additional nuclear encoded assembly factors. Complex I deficiency is a mitochondrial disorder usually associated with early-onset severe multisystem disorders characterized by highly variable clinical manifestations. Flavin adenine dinucleotide (FAD)-dependent oxidoreductase domain-containing protein 1 (FOXRED1) is a complex I assembly factor. To date, only five patients with mitochondrial complex I deficiency due to mutations in FOXRED1 have been characterized. Here, we describe a child with ataxia, epilepsy and psychomotor developmental delay carrying two heterozygous FOXRED1 variants, c.920G&gt, A (p.Gly307Glu) and c.733+1G&gt, A. We demonstrate the molecular mechanism supporting the pathogenicity of the FOXRED1 variants, showing a clear deficiency of complex I activity. The reduction in the steady-state level of complex I holoenzyme in patient fibroblasts, confirmed the pathogenicity of the variants and showed the molecular mechanism behind their pathogenicity. A comparison of the clinical presentation of the index case with the previously described cases allowed deepening our knowledge about the clinical variability associated with FOXRED1 defects.

Lysosomal diseases (LD) are a group of about 70 rare hereditary disorders (combined incidence 1:5000) in which diverse lysosomal functions are impaired, impacting multiple organs and systems. The first clinical signs and symptoms are usually unspecific and shared by hundreds of other disorders. Diagnosis of LD traditionally relies on performing specific enzymatic assays, if available, upon clinical suspicion of the disorder. However, the combination of the insidious onset of LD and the lack of awareness on these rare diseases among medical personnel results in undesirable diagnostic delays, with unchecked disease progression, appearance of complications and a worsened prognosis. We tested the usefulness of a next‐generation sequencing‐based gene panel for quick, early detection of LD among cases of idiopathic splenomegaly and/or thrombocytopenia, two of the earliest clinical signs observed in most LD. Our 73‐gene panel interrogated 28 genes for LD, 1 biomarker and 44 genes underlying non‐LD differential diagnoses. Among 38 unrelated patients, we elucidated eight cases (21%), five with LD (GM1 gangliosidosis, Sanfilippo disease A and B, Niemann‐Pick disease B, Gaucher disease) and three with non‐LD conditions. Interestingly, we identified three LD patients harboring pathogenic mutations in two LD genes each, which may result in unusual disease presentations and impact treatment. Turnaround time for panel screening and genetic validation was 1 month. Our results underline the usefulness of resequencing gene panels for quick and cost‐effective screening of LDs and disorders sharing with them early clinical signs.

Background: Glucose transporter type 1 deficiency syndrome (GLUT1DS) is caused by mutations in the SLC2A1 gene and produces seizures, neurodevelopmental impairment, and movement disorders. Ketogenic dietary therapies (KDT) are the gold standard treatment. Similar symptoms may appear in SLC2A1 negative patients. The purpose is to evaluate the effectiveness of KDT in children with GLUT1DS suspected SLC2A1 (+) and (-), side effects (SE), and the impact on patients nutritional status. Methods: An observational descriptive study was conducted to describe 18 children (January 2009–August 2020). SLC2A1 analysis, seizures, movement disorder, anti-epileptic drugs (AEDS), anthropometry, SE, and laboratory assessment were monitored baseline and at 3, 6, 12, and 24 months after the onset of KDT. Results: 6/18 were SLC2A1(+) and 13/18 had seizures. In these groups, the age for debut of symptoms was higher. The mean time from debut to KDT onset was higher in SLC2A1(+). The modified Atkins diet (MAD) was used in 12 (5 SLC2A1(+)). Movement disorder improved (4/5), and a reduction in seizures &gt, 50% compared to baseline was achieved in more than half of the epileptic children throughout the follow-up. No differences in effectiveness were found according to the type of KDT. Early SE occurred in 33%. Long-term SE occurred in 10, 5, 7, and 5 children throughout the follow-up. The most frequent SE were constipation, hypercalciuria, and hyperlipidaemia. No differences in growth were found according to the SLC2A1 mutation or type of KDT. Conclusions: CKD and MAD were effective for SLC2A1 positive and negative patients in our cohort. SE were frequent, but mild. Permanent monitoring should be made to identify SE and nutritional deficits.

The KCNQ2 gene codifies a subunit of the voltage-gated potassium M channel underlying the neuronal M-current. Classically, mutations in this gene have been associated with benign familial neonatal seizures, however, in recent years KCNQ2 mutations have been reported associated to early-onset epileptic encephalopathy. In this work, detailed familiar, clinical and genetic data were collected for 13 KCNQ2-positive patients revealed among a cohort of 80 epileptic pediatric probands from Spain who were analyzed through a targeted next-generation sequencing assay for 155 epilepsy-associated genes. This work shows for the first time the association between KCNQ2 mutations and startle attacks in 38% of patients, which opens the possibility to define electroclinical phenotypes associated to KCNQ2 mutations. It also demonstrates that KCNQ2 mutations contribute to an important percentage of Spanish patients with epilepsy. The study confirm the high genetic heterogeneity of this gene with 13 different mutations found, 10 of them novel and the better outcome of patients treated with sodium channel blockers.

The congenital disorders of glycosylation (CDG) are defects in glycoprotein and glycolipid glycan synthesis and attachment. They affect multiple organ/systems, but non-specific symptoms render the diagnosis of the different CDG very challenging. Phosphomannomutase 2 (PMM2)-CDG is the most common CDG, but advances in genetic analysis have shown others to occur more commonly than previously thought. The present work reports the clinical and mutational spectrum of 25 non-PMM2 CDG patients. The most common clinical symptoms were hypotonia (80%), motor or psychomotor disability (80%) and craniofacial dysmorphism (76%). Based on their serum transferrin isoform profile, 18 were classified as CDG-I and 7 as CDG-II. Pathogenic variations were found in 16 genes (ALG1, ALG6, ATP6V0A2, B4GALT1, CCDC115, COG7, DOLK, DPAGT1, DPM1, GFPT1, MPI, PGM1, RFT1, SLC35A2, SRD5A3, and SSR4). Overall, 27 variants were identified, 12 of which are novel. The results highlight the importance of combining genetic and biochemical analyses for the early diagnosis of this heterogeneous group of disorders.

There is growing evidence for inflammation as a cause and/or consequence of seizures in epilepsy as certain inflammatory biomarkers are elevated. Interleukin (IL)-6, with pro-inflammatory and epileptogenic effects, can perpetuate seizures. Clinical and experimental data support its involvement in acute refractory situations, with some cases responding to treatment with tocilizumab, a humanized monoclonal antibody against the IL-6 receptor. We describe 2 pediatric cases of refractory epilepsy with an abrupt debut responding to tocilizumab. Advances in the knowledge of inflammatory biomarkers involved in epilepsy and the targeted treatment could have important benefits, especially in cases that are refractory to usual treatments.

Supported in part by Instituto Carlos III (FIS PI12/00611, F.G.; FIS 14/00203, J.D.; and CM14/00081, T.A.), NIH RO1NS077851 (J.D.), Fundacio Cellex (J.D.), Mutual Medica, and a grant from the Spanish Society of Pediatric Neurology (T.A.)., Armangue, T., Moris, G., Cantarín-Extremera, V., Conde, C.E., Rostasy, K., Erro, M.E., Portilla-Cuenca, J.C., Turón-Viñas, E., Málaga, I., Muñoz-Cabello, B., Torres-Torres, C., Llufriu, S., González-Gutiérrez-Solana, L., González, G., Casado-Naranjo, I., Rosenfeld, M., Graus, F., Dalmau, J.

Hunter syndrome or mucopolysaccharidosis type II (MPSII) is a progressive multisystem X-linked lysosomal storage disease caused by mutations in the IDS gene that shows a wide spectrum of clinical symptoms and severity. Idursulfase, a specific enzyme replacement therapy (ERT) for MPSII, has been available since 2007. ERT, along with symptomatic management of patients, is fundamental for improving patient prognosis and quality of life. The aims of this study were to investigate whether Spanish pediatricians who are experts in managing the disease agreed with current international guidelines regarding MPSII patient diagnosis and follow-up; and to reach a consensus regarding which items are essential for the diagnosis, follow-up, and treatment of these patients in Spain. An advisory panel of 5 experts from the Hunter Spanish Working Group reviewed key studies, developed a questionnaire based on a modified Delphi method, sent the questionnaire to selected experts, and reviewed the responses. The final questionnaire had 83 items in the following categories: diagnosis, ERT considerations after diagnosis, Periodic assessments, and ERT considerations during follow-up. A total of 85 experts were invited to participate; 28 (35%) responded and showed a strong consensus for most items. The advisory panel decided not to perform a second Delphi round. There was strong agreement (>3.1 median value; range, 1 to 4) for 43/56 items in Diagnosis, for 4/6 items in “ERT considerations after diagnosis,” for 6/16 items in “Periodic assessments,” and for 3/5 items in “ERT considerations during follow-up.” Most responses were in agreement with international guidelines, and controversial items were discussed by the advisory panel. Based on the results, on the key studies, and on clinical experience and opinions, the panel developed and scheduled recommendations for the diagnosis and follow-up of patients with MPSII. An expert 5-person panel oversaw a Delphi survey of 28 pediatricians and reached a consensus on recommendations for the diagnosis and follow-up of MPSII patients. This document will help guide clinicians involved in the diagnosis, management, and treatment of MPSII.

Vanishing white matter (VWM) leukoencephalopathy is one of the most prevalent hereditary white matter diseases. It has been associated with mutations in genes encoding eukaryotic translation initiation factor ( eIF2B). We have compiled a list of all the patients diagnosed with VWM in Spain; we found 21 children. The first clinical manifestation in all of them was spasticity, with severe ataxia in six patients, hemiparesis in one child, and dystonic movements in another. They suffered from progressive cognitive deterioration and nine of them had epilepsy too. In four children, we observed optic atrophy and three also had progressive macrocephaly, which is not common in VWM disease. The first two cases were diagnosed before the 1980s. Therefore, they were diagnosed by necropsy studies. The last 16 patients were diagnosed according to genetics: we found mutations in the genes eIF2B5 (13 cases), eIF2B3 (2 cases), and eIF2B4 (1 case). In our report, the second mutation in frequency was c.318A>T; patients with this mutation all followed a slow chronic course, both in homozygous and heterozygous states. Previously, there were no other reports to confirm this fact. We also found some mutations not described in previous reports: c.1090C>T in eIF2B4, c.314A>G in eIF2B5, and c.877C>T in eIF2B5.

Two-thirds of patients with mucopolysaccharidosis type II (MPS II Hunter syndrome), a rare lysosomal disease characterized by iduronate-2-sulfatase deficiency, have cognitive impairment. This observational, prospective, longitudinal study (NCT01822184) assessed cognitive status and adaptive behavior in patients aged 2− 70 (n=26) were −2.4 (p=0.5657) at month 12 and −7.4 (p=0.1461) at month 24. Similarly, for VABS-II ABC scores, differences in LSM changes from baseline between the GCA subgroups (≤70/>70) were −1.9 (p=0.5545) at month 12 and 0.3 (p=0.9484) at month 24. Overall, cognitive ability and adaptive behavior in the pediatric MPS II population who completed this study remained relatively stable over 24 months. However, some patients experienced a rapid decline in cognitive ability, while others retained stable, but impaired, cognitive function. Shire funded this study and medical writing support.

Melatonin is synthesized from serotonin and it is excreted as sulphatoxymelatonin in urine. We aim to evaluate urinary sulphatoxymelatonin as a biomarker of brain serotonin status in a cohort of patients with mutations in genes related to serotonin biosynthesis. We analized urinary sulphatoxymelatonin from 65 healthy subjects and from 28 patients with genetic defects. A total of 18 patients were studied: 14 with autosomal dominant and recessive guanosine triphosphate cyclohydrolase-I deficiency; 3 with sepiapterin reductase deficiency; and 1 with aromatic L-amino acid decarboxylase deficiency. Further 11 patients were studied after receiving serotoninergic treatment (serotonin precursors, monoamine oxidase inhibitors, selective serotonin re-uptake inhibitors): 5 with aromatic L-amino acid decarboxylase deficiency; 1 with sepiapterin reductase deficiency; 3 with dihydropteridine reductase deficiency; and 2 with 6-pyruvoyltetrahydropterin synthase deficiency. Among the patients without therapy, 6 presented low urinary sulphatoxymelatonin values, while most of the patients with guanosine triphosphate cyclohydrolase-I deficiency showed normal values. 5 of 11 patients under treatment presented low urine sulphatoxymelatonin values. Thus, decreased excretion of sulphatoxymelatonin is frequently observed in cases with severe genetic disorders affecting serotonin biosynthesis. In conclusion, sulphatoxymelatonin can be a good biomarker to estimate serotonin status in the brain, especially for treatment monitoring purposes.

Background We aim to delineate the progression of cerebellar syndrome in children with phosphomannomutase-deficiency (PMM2-CDG) using the International Cooperative Ataxia Rating Scale (ICARS). We sought correlation between cerebellar volumetry and clinical situation. We prospectively evaluated PMM2-CDG patients aged from 5 to 18 years through ICARS at two different time points set apart by at least 20 months. We reviewed available MRIs and performed volumetric analysis when it was possible. Results From the eligible 24, four patients were excluded due to severe mental disability (n = 2) and supratentorial lesions (n = 2). Two different ICARS evaluations separated by more than 20 months were available for 14 patients showing an improvement in the cerebellar syndrome: ICARS1: 35.71 versus ICARS2: 30.07 (p

Summary Purpose Pyridoxine-dependent epilepsy seizure (PDE; OMIM 266100) is a disorder associated with severe seizures that can be controlled pharmacologically with pyridoxine. In the majority of patients with PDE, the disorder is caused by the deficient activity of the enzyme α-aminoadipic semialdehyde dehydrogenase (antiquitin protein), which is encoded by the ALDH7A1 gene. The aim of this work was the clinical, biochemical, and genetic analysis of 12 unrelated patients, mostly from Spain, in an attempt to provide further valuable data regarding the wide clinical, biochemical, and genetic spectrum of the disease. Methods The disease was confirmed based on the presence of α-aminoadipic semialdehyde (α-AASA) in urine measured by liquid chromatography tandem mass spectrometry (LC-MS/MS) and pipecolic acid (PA) in plasma and/or cerebrospinal fluid (CSF) measured by high performance liquid chromatography (HPLC)/MS/MS and by sequencing analysis of messenger RNA (mRNA) and genomic DNA of ALDH7A1. Key Findings Most of the patients had seizures in the neonatal period, but they responded to vitamin B6 administration. Three patients developed late-onset seizures, and most patients showed mild-to-moderate postnatal developmental delay. All patients had elevated PA and α-AASA levels, even those who had undergone pyridoxine treatment for several years. The clinical spectrum of our patients is not limited to seizures but many of them show associated neurologic dysfunctions such as muscle tone alterations, irritability, and psychomotor retardation. The mutational spectrum of the present patients included 12 mutations, five already reported (c.500A>G, c.919C>T, c.1429G>C c.1217_1218delAT, and c.1482-1G>T) and seven novel sequence changes (c.75C>T, c.319G>T, c.554_555delAA, c.757C>T, c.787 + 1G>T, c.1474T>C, c.1093-?_1620+?). Only one mutation, p.G477R (c.1429G>C), was recurrent; this was detected in four different alleles. Transcriptional profile analysis of one patient's lymphoblasts and ex vivo splicing analysis showed the silent nucleotide change c.75C>T to be a novel splicing mutation creating a new donor splice site inside exon 1. Antisense therapy of the aberrant mRNA splicing in a lymphoblast cell line harboring mutation c.75C>T was successful. Significance The present results broaden our knowledge of PDE, provide information regarding the genetic background of PDE in Spain, afford data of use when making molecular-based prenatal diagnosis, and provide a cellular proof-of concept for antisense therapy application.

The transition process from paediatric to adult care is a subject of great interest in recent years, especially in chronic diseases with childhood onset, such as inborn errors of metabolism (IEM). Advances in diagnosis and treatment of these diseases have improved their prognosis, with a high number of patients with IEM who currently reach adult age and need to be attended to by non-paediatric professionals. The objective of this work is to establish action guidelines so that the specialists involved can guarantee a successful transition of these patients' healthcare.After carrying out a bibliographic review of the subject, the authors, beginning with their own experience, produced an initial document which was subjected to successive debates until the final document was obtained. The consensus recommendation was decided by the majority in case of criterion discrepancy.A series of recommendations are presented for the best clinical management of the transitions of care of patients with IEM from the paediatric to adult care setting in order to achieve the best results in this process given the special characteristics of this patient subgroup and the main difficulties entailed in the transition process.The role of the internal medicine doctor in this transition process and correct interrelation with the paediatric and social setting is stressed. Furthermore, actions and attitudes are suggested to improve the quality of said transition.

Objective: Sepiapterin reductase deficiency (SRD) is an under-recognized levodopa-responsive disorder. We describe clinical, biochemical, and molecular findings in a cohort of patients with this treatable condition. We aim to improve awareness of the phenotype and available diagnostic and therapeutic strategies to reduce delayed diagnosis or misdiagnosis, optimize management, and improve understanding of pathophysiologic mechanisms.Methods: Forty-three individuals with SRD were identified from 23 international medical centers. The phenotype and treatment response were assessed by chart review using a detailed standardized instrument and by literature review for cases for which records were unavailable.Results: In most cases, motor and language delays, axial hypotonia, dystonia, weakness, oculogyric crises, and diurnal fluctuation of symptoms with sleep benefit become evident in infancy or childhood. Average age of onset is 7 months, with delay to diagnosis of 9.1 years. Misdiagnoses of cerebral palsy (CP) are common. Most patients benefit dramatically from levodopa/carbidopa, often with further improvement with the addition of 5-hydroxytryptophan. Cerebrospinal fluid findings are distinctive. Diagnosis is confirmed by mutation analysis and/or enzyme activity measurement in cultured fibroblasts.Interpretation: Common, clinical findings of SRD, aside from oculogyric crises and diurnal fluctuation, are nonspecific and mimic CP with hypotonia or dystonia. Patients usually improve dramatically with treatment. Consequently, we recommend consideration of SRD not only in patients with levodopa-responsive motor disorders, but also in patients with developmental delays with axial hypotonia, and patients with unexplained or atypical presumed CP. Biochemical investigation of cerebrospinal fluid is the preferred method of initial investigation. Early diagnosis and treatment are recommended to prevent ongoing brain dysfunction. ANN NEUROL 2012; 71: 520-530

Due to an unfortunate error during the typesetting process, the collaborators were presented incorrectly. Collaborators of the CDG Spanish-Consortium Sergio Aguilera-Albesa, MD PhD1 Ramon Cancho Candela, MD PhD2Ma Llanos CarrascoMarina,MD3 Francisco Carratala,MD PhD4Ma Luz Couce, MDPhD5 Ana Felipe,MD6 oscar Garcia,MD7Ma TeresaGarcia-Silva,MD PhD8 Luis G Gutierrez-Solana, MD PhD9 Alfons Macaya, MD PhD6 Ma Concepcion Miranda, MD PhD10 Laura Lopez, MD9 Eduardo Lopez-Laso, MD PhD11MPilar Poo,MD PhD12 Pilar Quijada-Fraile,MD PhD8 Bernabe Robles, MD,PhD13 Concepcion Sierra-Corcoles, MD14 Ramon Velazquez- Fragua, MD15 1. Pediatric Neurology Unit, Department of Pediatrics, Navarra Hospital, Pamplona, Spain 2. Pediatric Neurology Unit. Pediatrics Department. Hospital Universitario Rio Hortega. Valladolid, Spain. 3. Neuropediatric Department, Pediatric Service, Hospital Universitario Severo Ochoa. Leganes, Madrid, Spain. 4. Pediatric Neurology Department, University Hospital Sant Joan d’Alacant, Spain. 5. Unit of Diagnosis and Treatment of CongenitalMetabolic Diseases. Department of Pediatrics. Hospital Clinico Universitario de Santiago. CIBERER. Health Research Institute of Santiago de Compostela (IDIS), Santiago de Compostela, Spain. 6. Grup de Recerca en Neurologia Pediatrica, Institut de Recerca Vall d’Hebron, Universitat Autonoma de Barcelona, Seccio de Neurologia Pediatrica, Hospital Universitari Vall d’Hebron, Barcelona, Spain. 7. Pediatric Department, Hospital Virgen de la Salud, Toledo, Spain. 8. Unidad de Enfermedades Mitocondriales-Enfermedades Metabolicas Hereditarias. Dpto. de Pediatria, Instituto de Investigacion i+12, Hospital Universitario 12 de Octubre- CIBERER-ISCIII, Universidad Complutense de Madrid, Spain. 9. Unit of Child Neurology, Department of Pediatrics, Hospital Infantil Universitario Nino Jesus de Madrid, Madrid, Spain 10. Pediatric Neurology Unit, H.G.U Gregorio Maranon, Madrid, Spain 11. Maimonides Biomedical Research Institute of Cordoba (IMIBIC), Pediatric Neurology Unit, Reina Sofia University Hospital, CIBERER, Cordoba, Spain. 12. Neuropediatric, Radiology and Clinical Biochemistry Departments, Hospital Sant Joan de Deu, Barcelona, Spain. U-703 Centre for Biomedical Research on Rare Diseases (CIBER-ER), Instituto de Salud Carlos III, Barcelona, Spain. 13.Neurology Department, Hospital General de Sant Boi, Parc Sanitari Sant Joan de Deu, Sant Boi, Barcelona, Spain. 14. Unidad de Neuropediatria, Hospital de Jaen, Jaen, Spain. 15. Pediatric Neurology Department, Hospital Universitario La Paz, Madrid, Spain. We apologize for this mistake. The original article was corrected.