The clinical and genetic spectrum of inherited glycosylphosphatidylinositol deficiency disorders.

Inherited glycosylphosphatidylinositol deficiency disorders (IGDs) are a group of rare multisystem disorders arising from pathogenic variants in glycosylphosphatidylinositol anchor pathway (GPI-AP) genes. Despite associating 24 of at least 31 GPI-AP genes with human neurogenetic disease, prior reports are limited to single genes without consideration of the GPI-AP as a whole and with limited natural history data. In this multinational retrospective observational study, we systematically analyse the molecular spectrum, phenotypic characteristics, and natural history of 83 individuals from 75 unique families with IGDs, including 70 newly reported individuals: the largest single cohort to date. Core clinical features were developmental delay or intellectual disability (DD/ID, 90%), seizures (83%), hypotonia (72%), and motor symptoms (64%). Prognostic and biologically significant neuroimaging features included cerebral atrophy (75%), cerebellar atrophy (60%), callosal anomalies (57%), and symmetric restricted diffusion of the central tegmental tracts (60%). Sixty-one individuals had multisystem involvement including gastrointestinal (66%), cardiac (19%), and renal (14%) anomalies. Though dysmorphic features were appreciated in 82%, no single dysmorphic feature had a prevalence >30%, indicating substantial phenotypic heterogeneity. Follow-up data were available for all individuals, 15 of whom were deceased at the time of writing. Median age at seizure onset was 6 months. Individuals with variants in synthesis stage genes of the GPI-AP exhibited a significantly shorter time to seizure onset than individuals with variants in transamidase and remodelling stage genes of the GPI-AP (P=0.046). Forty individuals had intractable epilepsy. The majority of individuals experienced delayed or absent speech (95%); motor delay with non-ambulance (64%); and severe-to-profound DD/ID (59%). Individuals with a developmental epileptic encephalopathy (51%) were at greater risk of intractable epilepsy (P=0.003), non-ambulance (P=0.035), ongoing enteral feeds (P<0.001), and cortical visual impairment (P=0.007). Serial neuroimaging showed progressive cerebral volume loss in 87.5% and progressive cerebellar atrophy in 70.8%, indicating a neurodegenerative process. Genetic analyses identified 93 unique variants (106 total), including 22 novel variants. Exploratory analyses of genotype-phenotype correlations using unsupervised hierarchical clustering identified novel genotypic predictors of clinical phenotype and long-term outcome with meaningful implications for management. In summary, we expand both the mild and severe phenotypic extremities of the IGDs; provide insights into their neurological basis; and, vitally, enable meaningful genetic counselling for affected individuals and their families.

Diagnostic challenge in children with an acquired demyelinating syndrome: an illustrative case report.

The clinical-radiological and biological overlap of the spectrum of pediatric demyelinating disorders makes the diagnostic process of a child with an acquired demyelinating syndrome truly challenging. We present a 9-year-old girl with subacute symptoms of severe decrease in bilateral visual acuity and gait ataxia. An urgent MRI showed inflammatory-demyelinating lesions affecting the periaqueductal gray matter, the cerebellar hemispheres, the area postrema as well as both optic nerves and chiasm. Likewise, multisegmental involvement of the cervical and dorsal spinal cord was found, with short and peripheral lesions. Anti myelin oligodendrocyte glycoprotein (MOG) antibodies (Abs) were positive in cerebrospinal fluid (CSF) and weakly in serum. Oligoclonal bands (OB) were positive in CSF. Based on all this, the diagnosis of MOG antibody disease (MOGAD) with a neuromyelitis optica spectrum disorder (NMOSD)-like picture was made. Given the good clinical and radiological recovery after the acute phase treatment, and that anti MOG Abs became negative, it was decided to keep the patient without specific treatment. However, during follow-up, while the patient was asymptomatic, a control brain MRI showed the appearance of new lesions with morphology and topography suggestive of multiple sclerosis (MS). This, added to the presence of OB, made the diagnosis of pediatric-onset MS (POMS) likely. Immunosuppressive treatment was restarted with a good response since then. Unlike adult-onset MS, children with POMS may usually not have entirely typical clinical and radiological features at presentation. In many cases, the time factor and close clinical and radiological monitoring could be critical to make an accurate diagnosis.

Impact of COVID19 pandemic on patients with rare diseases in Spain, with a special focus on inherited metabolic diseases.

Introduction: The Covid-19 pandemic soon became an international health emergency raising concern about its impact not only on physical health but also on quality of life and mental health. Rare diseases are chronically debilitating conditions with challenging patient care needs. We aimed to assess the quality of life and mental health of patients with rare diseases in Spain, with a special focus on inherited metabolic disorders (IMD). Methods: A prospective case-control study was designed, comparing 459 patients suffering from a rare disease (including 53 patients with IMD) and 446 healthy controls. Quality of life (QoL) and mental health were assessed using validated scales according to age: KINDL-R and the Pediatric Symptom Checklist (PSC) for children and the WhoQoL-Bref questionnaire, GAD and PHQ-9 in adults. Results: First, children and adults (but not adolescents) with IMD showed greater psychological effects than controls (p = 0.022, p = 0.026 respectively). Second, when comparing QoL, only adult patients with IMD showed worse score than controls (66/100 vs 74,6/100 respectively, p = 0.017). Finally, IMD had better quality of life than other rare neurological and genetic diseases (p = 0.008) or other rare diseases (p < 0.001 respectively) but similar alteration of the mental status. Conclusions: Our data show that the pandemic had a negative impact on mental health that is more evident in the group of patients with IMD. Young age would behave as a protective factor on the perception of QoL. Furthermore, patients with IMD show a better QoL than other rare diseases.

Non-ADEM encephalitis in patients with myelin oligodendrocyte glycoprotein antibodies: a systematic review.

BACKGROUND AND PURPOSE: Non-(acute disseminated encephalomyelitis) (non-ADEM) encephalitis and/or fluid attenuated inversion recovery hyperintense lesions in anti-myelin-oligodendrocyte-glycoprotein-associated encephalitis with seizures (FLAMES) are rarely described in patients with myelin oligodendrocyte glycoprotein (MOG) antibodies (Abs). The aim was (i) to describe the clinical features and disease course of children and adults with non-ADEM encephalitis and/or FLAMES associated with MOG Abs and (ii) to describe their association with other central nervous system autoantibodies. METHODS: This was a systematic review following the PRISMA guidelines. Patients fulfilled criteria for non-ADEM encephalitis and/or FLAMES, and all were MOG Ab positive. RESULTS: In total, 83 (79%) patients with non-ADEM encephalitis (48 also had FLAMES) and 22 (21%) with isolated FLAMES were included. At the first episode, children (n = 45) had more infections (11/45, 24.4%; p = 0.017) and more of the phenotype consisting of non-ADEM encephalitis (42/45, 93.3%; p = 0.014) than adults (n = 38). Children had more episodes consistent with working memory deficits (25/54, 46.3%; p = 0.014) but fewer psychiatric symptoms (16/54, 29.6%; p = 0.002). Twenty-eight (40.6%) of 69 patients had N-methyl-d-aspartate receptor (NMDAR) Abs in cerebrospinal fluid (CSF), being more frequent in adults (19/29, 65.5%; p < 0.001). Compared to negatives, positive CSF NMDAR Abs had more relapses (14/20, 70%; p = 0.050), required ventilatory support more frequently (8/34, 23.5%; p = 0.009) and had more psychiatric episodes (28/34, 82%; p < 0.001) or abnormal movements (14/34, 41.2%; p = 0.008). Apart from an older age in FLAMES, positive and negative CSF NMDAR Ab groups shared similar features. CONCLUSION: Non-ADEM encephalitis patients with MOG Abs show specific clinical and radiological features, depending on the age at first episode. The presence of MOG Abs in non-ADEM encephalitis patients should not rule out to test other autoantibodies, especially concomitant NMDAR Abs in patients with suggestive symptoms such as behavioural or movement alterations.

Influence of initial clinical suspicion on the diagnostic yield of laboratory enzymatic testing in lysosomal storage disorders. Experience from a multispecialty hospital.

Lysosomal storage disorders (LSD) are a group of inherited metabolic diseases mainly caused by a deficiency of lysosomal hydrolases, resulting in a gradual accumulation of non-degraded substrates in different tissues causing the characteristic clinical manifestations of such disorders. Confirmatory tests of suspected LSD individuals include enzymatic and genetic testing. A well-oriented clinical suspicion can improve the cost-effectiveness of confirmatory tests and reduce the time expended to achieve the diagnosis. Thus, this work aims to retrospectively study the influence of clinical orientation on the diagnostic yield of enzymatic tests in LSD by retrieving clinical, biochemical, and genetic data obtained from subjects with suspicion of LSD. Our results suggest that the clinical manifestations at the time of diagnosis and the initial clinical suspicion can have a great impact on the diagnostic yield of enzymatic tests, and that clinical orientation performed in specialized clinical departments can contribute to improve it. In addition, the analysis of enzymatic tests as the first step in the diagnostic algorithm can correctly guide subsequent confirmatory genetic tests, in turn increasing their diagnostic yield. In summary, our results suggest that initial clinical suspicion plays a crucial role on the diagnostic yield of confirmatory enzymatic tests in LSD.

Neurological Short-Term Outcomes of a Cohort of Children Born to Zika Virus-Infected Mothers in Barcelona.

Zika virus (ZIKV) is a vector-borne flavivirus with a known teratogenic effect, yet the full spectrum has not been delineated. Studies on endemic areas tried to characterize the clinical outcomes of ZIKV intrauterine exposure. We aimed to describe early neurodevelopmental outcomes on prenatally ZIKV-exposed children in a non-endemic ZIKV area. This is a prospective observational cohort study conducted from May 2016 to December 2021 at Hospital Universitari Vall d'Hebron in Barcelona, Catalonia, Spain. We monitored for up to 24 months 152 children extracted from a pregnant women cohort with suspected ZIKV infection; eleven women (11/150; 7.3%) fulfilled the criteria for a confirmed ZIKV infection. Among the 152 children included, we describe two cases of congenital ZIKV syndrome (CZS) born from women with a confirmed ZIKV infection. Additionally, we describe five cases of other potentially ZIKV-related outcomes (OPZROs), all with normal birth cranial circumference and born to women with probable ZIKV infection. The low exposed prevalence of adverse outcomes in asymptomatic children at birth in a non-endemic area suggests that close follow-up should be addressed by primary care pediatricians instead of pediatric specialists. Further studies are needed to assess the effects of ZIKV intrauterine exposure beyond two years of life.

Diagnòstic i maneig de la paràlisi facial de Bell / Diagnosis and management of facial Bell's palsy

Fonament. La paràlisi facial perifèrica idiopàtica, o paràliside Bell, és la paràlisi facial més freqüent en la poblaciópediàtrica. La clínica pot incloure manifestacions motores,sensitives, autonòmiques i emocionals. Representa undiagnòstic d’exclusió, i és necessari descartar la presènciade signes o símptomes d’alarma que suggereixin una etiologia diferent. El tractament es basa en mesures de protecció i hidratació ocular, i l’ús de corticoesteroides en l’edatpediàtrica és controvertit.Objectiu. Descriure la clínica, el diagnòstic diferencial i eltractament de la paràlisi de Bell, analitzant l’evidència disponible actualment sobre l’ús de corticoesteroides.Mètode. Es fa una revisió bibliogràfica.Resultats. Els cinc treballs analitzats, incloent-hi dues revisions sistemàtiques, suggereixen la manca de benefici delscorticoesteroides, ja que no observen que tinguin impacteen la recuperació experimentada pels pacients pediàtrics.Destaca, però, l’absència d’estudis prospectius aleatoritzats, de manera que l’evidència prové de treballs amb graud’evidència baix.Conclusions. La paràlisi de Bell en infants presenta taxes derecuperació espontània molt elevades (85-97%), tot i queles seqüeles també són possibles. Actualment, el tractament es basa en mesures generals. És dubtosa la necessitat d’ús de corticoesteroides, a l’espera de la publicació denous treballs els pròxims anys. (AU)

Fundamento. La parálisis facial periférica idiopática, o parálisis deBell, es la parálisis facial más frecuente en la población pediátrica. La clínica puede incluir manifestaciones motoras, sensitivas,autonómicas y emocionales. Representa un diagnóstico de exclusión, y es necesario descartar la presencia de signos o síntomas dealarma que sugieran una etiología diferente. El tratamiento se basaen medidas de protección e hidratación ocular, y el uso de loscorticosteroides en la edad pediátrica es controvertido.Objetivo. Describir la clínica, el diagnóstico diferencial y el tratamiento de la parálisis de Bell, analizando la evidencia disponibleactualmente sobre el uso de corticosteroides. Método. Se realiza una revisión bibliográfica.Resultados. Los cinco trabajos analizados, incluyendo dos revisiones sistemáticas, sugieren la falta de beneficio de los corticosteroides, pues no observan impacto de estos en la recuperaciónexperimentada por los pacientes pediátricos. Destaca, no obstante, la ausencia de estudios prospectivos aleatorizados, por loque la evidencia proviene de trabajos con un grado de evidenciabajo.Conclusiones. La parálisis de Bell en niños presenta tasas de recuperación espontánea muy elevadas (85-97%), aunque las secuelastambién son posibles. Actualmente, el tratamiento se basa enmedidas generales. Es dudosa la necesidad de uso de corticosteroides, a la espera de la publicación de nuevos trabajos en lospróximos años. (AU)

Background. Idiopathic peripheral facial palsy, or Bell’s palsy, isthe most common facial paralysis in the pediatric population. Theclinical presentation can include motor, sensory, autonomic, andemotional manifestations. It represents a diagnosis of exclusionand thus it is always necessary to rule out the presence of alarmsigns or symptoms that would suggest a different etiology.Treatment is based on eye protection and hydration measures,while the application of corticosteroids in children is controversial.Objective. To describe the clinical characteristics, differential diagnosis, and treatment of Bell’s palsy, including a review of the available evidence on the use of corticosteroids.Method. Literature review.Results. The five studies analysed, including two systematic reviews, suggest the lack of benefit of corticosteroids, since an impact on recovery experienced by pediatric patients has not beendocumented. However, the absence of prospective randomizedstudies limits the validity of the findings, since the only data available originates from studies with a low level of evidence.Conclusions. Bell’s palsy in children presents high recovery rates(85-97%), although sequelae are possible. Current treatment isbased in general supportive measures. The need of corticoids isstill a controversial issue and further research is needed. (AU)

Error innat del metabolisme diagnosticat després d'encefalopatia hiperamonièmica induïda per valproat / Error innato del metabolismo diagnosticado tras encefalopatía hiperamoniémica inducida por valproato / Inborn error of metabolism diagnosed after valproate -induced hyperammonemic encephalopathy

Introducció: L’àcid valproic és un fàrmac antiepilèptic utilitzat àmpliament, tant per tractar l’epilèpsia com en patologia psiquiàtrica o migranya. Tot i que els seus efectessecundaris més freqüents són lleus i coneguts, determinatspacients poden presentar reaccions idiosincràtiques menysconegudes i potencialment greus. Cas clínic: Pacient de 10 anys amb antecedent d’epilèpsia,en el moment actual sense tractament. En el context denova crisi i administració d’àcid valproic, presenta un quadre d’instauració gradual caracteritzat per somnolència,vòmits i alteració conductual amb agressivitat verbal i física. Davant la sospita de reacció adversa farmacològica,se sol·liciten nivells plasmàtics de valproat (normals), nivells d’amoni (elevats) i funció hepàtica i renal (normals). L’electroencefalograma evidencia un alentiment generalitzat compatible amb encefalopatia. L’estudi metabòlic ensang i orina identifica alteracions compatibles amb un trastorn de la β-oxidació dels àcids grassos de cadena mitjana. L’estat clínic del pacient millora al cap de 48 hores del’ingrés amb la retirada del fàrmac, dieta absoluta ambseroterapia i administració de carnitina i àcid carglúmic. Comentaris: Per la seva simptomatologia inespecífica,l’encefalopatia per àcid valproic es pot confondre amb altres patologies, per la qual cosa és important tenir un elevat índex de sospita i fer estudis bioquímics complerts,tant per confirmar el diagnòstic com per excloure altresmalalties de base.(AU)

Introducción: El ácido valproico es un antiepiléptico muy empleadopara el tratamiento de distintas formas de epilepsia, además depara patología psiquiátrica o migraña. Aunque sus efectos adversos son en su mayoría leves y bien conocidos, algunos pacientespueden presentar reacciones idiosincráticas menos conocidas ypotencialmente graves. Caso clínico: Paciente de 10 años, con antecedentes de epilepsia,actualmente sin tratamiento. Tras una nueva crisis y en tratamiento con ácido valproico, presenta un cuadro de instauración radual con somnolencia, vómitos y alteración conductual conagresividad verbal y física. Ante la sospecha de una reacción farmacológica adversa, se solicitan niveles plasmáticos de valproato(normales), niveles de amonio (elevados) y función hepatorrenal(normal). El electroencefalograma evidencia un enlentecimientogeneralizado compatible con encefalopatía. El estudio metabólicoen sangre y orina identifica alteraciones compatibles con un defecto en la β-oxidación de los ácidos grasos de cadena media. Elestado clínico del paciente mejoró a las 48 horas del ingreso conla retirada del fármaco, dieta absoluta y sueroterapia, administración de carnitina endovenosa y ácido carglúmico.Comentarios: Por su sintomatología inespecífica, la encefalopatíapor ácido valproico puede confundirse con otras entidades, por loque es importante tener un alto índice de sospecha y realizar estudios bioquímicos completos tanto para la confirmación del diagnóstico como para excluir otras enfermedades de base.(AU)

Introduction: Valproic acid is an antiepileptic drug that is commonly used not only to treat epilepsy, but also for several psychiatric conditions and migraine. Most of its side effects are mild andwell known. However, some patients may present less knownidiosyncratic, potentially life-threatening side effects. Case report: A 10-year-old boy with history of epilepsy, currently offtreatment, presented with a new seizure. After treatment with valproic acid was initiated, the patient progressively developed altered consciousness with drowsiness, vomiting and physical andverbal aggressiveness. Valproate plasma levels and liver and renalfunction were withing normal limits, but ammonia levels were elevated. An electroencephalogram showed diffuse slow wave activity,suggestive of encephalopathy. Metabolic studies, in blood andurine, identified alterations on β-oxidation of medium chain fattyacid pathways. The patient’s clinical condition improved within 48hours after discontinuation of valproic acid, fasting, and administration of intravenous fluids, carglumic acid and carnitine. Comments: Because of its unspecific symptoms, hyperammonemicencephalopathy induced by valproate can be confused with otherillnesses. For this reason, it is important to have a high level ofsuspicion and perform a comprehensive laboratory evaluation toconfirm the diagnosis and rule out other conditions.(AU)

Age-dependent favorable visual recovery despite significant retinal atrophy in pediatric MOGAD: how much retina do you really need to see well?

BACKGROUND: To investigate age-related severity, patterns of retinal structural damage, and functional visual recovery in pediatric and adult cohorts of myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) optic neuritis (ON). METHODS: All MOGAD patients from the 5 participating centers were included. Patients with initial manifestation <18 years were included in the pediatric (MOGADped) cohort and patients with ≥18 years in the adult (MOGADadult) cohort. For patients with MOGAD ON, examinations at least ≥6 months after ON onset were included in the analyses. Using spectral domain optical coherence tomography (SD-OCT), we acquired peripapillary retinal nerve fiber layer thickness (pRNFL) and volumes of combined ganglion cell and inner plexiform layer (GCIPL). High- and 2.5% low-contrast visual acuity (HCVA, LCVA) and visual-evoked potentials (VEP) were obtained. RESULTS: Twenty MOGADped (10.3±3.7 years, 30 MOGAD ON eyes) and 39 MOGADadult (34.9±11.6 years, 42 MOGAD ON eyes) patients were included. The average number of ON episodes per ON eye was similar in both groups (1.8±1.3 and 2.0±1.7). In both pediatric and adult MOGAD, ON led to pronounced neuroaxonal retinal atrophy (pRNFL: 63.1±18.7 and 64.3±22.9 µm; GCIPL: 0.42±0.09 and 0.44±0.13 mm3, respectively) and moderate delay of the VEP latencies (117.9±10.7 and 118.0±14.5 ms). In contrast, visual acuity was substantially better in children (HCVA: 51.4±9.3 vs. 35.0±20.6 raw letters, p=0.001; LCVA: 22.8±14.6 vs. 13.5±16.4, p=0.028). Complete visual recovery (HCVA-logMAR 0.0) occurred in 73.3% of MOGADped and 31% MOGADadults ON eyes, while 3.3% and 31% demonstrated moderate to severe (logMAR > 0.5) visual impairment. Independent of retinal atrophy, age at ON onset significantly correlated with visual outcome. CONCLUSION: Pediatric MOGAD ON showed better visual recovery than adult MOGAD ON despite profound and almost identical neuroaxonal retinal atrophy. Age-related cortical neuroplasticity may account for the substantial discrepancy between structural changes and functional outcomes.

Codi ictus pediàtric a Catalunya / No disponible

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Primary endovascular treatment for acute ischemic stroke in teenage patients: a short case series.

PURPOSE: To analyze the safety and efficacy of primary endovascular treatment (EVT) for acute ischemic stroke (AIS) in patients younger than 18 years of age. METHODS: Review of 4 patients < 18 years of age with AIS, prospectively enrolled in an electronic database registry for acute ischemic stroke patients who underwent thrombectomy at tertiary centers, from January 2011 to February 2017. Clinical and imaging data were analyzed. RESULTS: All patients were female. Patients 1 to 4 were 14, 13, 16, and 13 years old, respectively. Patients 1 and 3 had left middle cerebral artery occlusion, patient 2 basilar occlusion, and patient 4 right tandem occlusion. Mean NIHSS score was 13 (7-19) on arrival and 4 (0-5) at 24 h. Patient 2 had Osler-Weber-Rendu disease and patient 4 a previously surgically repaired complete atrioventricular canal. All patients presented with clinical-radiological mismatch. CT/CTA was used in patients 1 and 4 and MRI/MRA in patients 2 and 3. Stent retriever was used in 3 patients (patients 1, 3, and 4) and direct aspiration first-pass technique in 1 (patient 2). All 4 procedures resulted in successful recanalization and 3-month functional independence. CONCLUSION: Primary EVT is reported in patients 13 to 16 years of age with AIS due to large vessel occlusion and clinical-radiological mismatch. Procedures were safe and effective with prompt recanalization and good clinical outcome.

Associations of paediatric demyelinating and encephalitic syndromes with myelin oligodendrocyte glycoprotein antibodies: a multicentre observational study.

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) and 17 (15%) moderate to severe deficits (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.

Homomeric Kv7.2 current suppression is a common feature in KCNQ2 epileptic encephalopathy.

OBJECTIVE: To gain insight into the mechanisms underlying KCNQ2 encephalopathy by examining the electrophysiologic properties of mutant Kv7.2 channels in different multimeric configurations. METHODS: We analyzed the genotype-phenotype relationship in 4 patients with KCNQ2 encephalopathy and performed electrophysiologic analysis of M-currents mediated by homomeric Kv7.2 or heteromeric Kv7.2/Kv7.3 channels. RESULTS: Negligible or no current was recorded in cells expressing homomeric E130K, W270R, or G281R de novo mutants, and it was reduced by more than 90% for the L243F maternally inherited mutant. The E130K and G281R mutants presented a marked dominant-negative behavior, whereas the current density was partially reduced (L243F) or not affected (W270R) when coexpressed with wild-type Kv7.2 subunits. In contrast, the extent of Kv7.3 "rescue," which yields negligible currents on its own, followed the sequence E130K > L243F > W270R, whereas no rescue was observed with the G281R mutant. No significant effects on current density were observed when subunits were expressed in a 0.5:0.5:1.0 (Kv7.2:mutant:Kv7.3) DNA ratio to mimic the genetic balance. There was an increase in sensitivity to phosphatidylinositol 4,5-bisphosphate (PIP2 ) depletion for W270R/Kv7.3, but no substantial differences were observed when the mutated subunits were coexpressed with Kv7.2 or both Kv7.2 and Kv7.3. SIGNIFICANCE: There was a marked disparity of the impact of these mutations on Kv7.2 function, which varied on association with Kv7.2 or Kv7.3 subunits. Current density of homomeric channels was the most reliable property relating Kv7.2 function to encephalopathy, but other factors are required to explain the milder phenotype for some individuals carrying the maternally inherited L243F mutation. We hypothesize that the role of homomeric Kv7.2 channels for fine-tuning neuronal connections during development is critical for the severity of the KCNQ2 encephalopathy.

Enterovirus y complicaciones neurológicas / Enterovirus and neurological complications

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Brote de enfermedad neurológica aguda asociada a enterovirus en Cataluña: aspectos neuropediátricos / Outbreak of acute neurological disease associated to enterovirus in Catalonia: neuropaediatric aspects

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