Recurrent de novo missense variants in GNB2 can cause syndromic intellectual disability.

PURPOSE: Binding proteins (G-proteins) mediate signalling pathways involved in diverse cellular functions and comprise Gα and Gßγ units. Human diseases have been reported for all five Gß proteins. A de novo missense variant in GNB2 was recently reported in one individual with developmental delay/intellectual disability (DD/ID) and dysmorphism. We aim to confirm GNB2 as a neurodevelopmental disease gene, and elucidate the GNB2-associated neurodevelopmental phenotype in a patient cohort. METHODS: We discovered a GNB2 variant in the index case via exome sequencing and sought individuals with GNB2 variants via international data-sharing initiatives. In silico modelling of the variants was assessed, along with multiple lines of evidence in keeping with American College of Medical Genetics and Genomics guidelines for interpretation of sequence variants. RESULTS: We identified 12 unrelated individuals with five de novo missense variants in GNB2, four of which are recurrent: p.(Ala73Thr), p.(Gly77Arg), p.(Lys89Glu) and p.(Lys89Thr). All individuals have DD/ID with variable dysmorphism and extraneurologic features. The variants are located at the universally conserved shared interface with the Gα subunit, which modelling suggests weaken this interaction. CONCLUSION: Missense variants in GNB2 cause a congenital neurodevelopmental disorder with variable syndromic features, broadening the spectrum of multisystem phenotypes associated with variants in genes encoding G-proteins.

Neurological and cognitive outcomes after antibody-negative autoimmune encephalitis in children.

AIM: To characterize the neurological and cognitive outcomes in children with antibody-negative autoimmune encephalitis (Ab-negative AE). METHOD: A cohort of children presenting to our institution over a 10-year period with autoimmune encephalitis was identified by structured retrospective review of medical records. Clinical features at presentation and final follow-up were recorded. Neuropsychological testing was performed in a subset of patients. Outcomes after Ab-negative AE were compared with outcomes after N-methyl-D-aspartate receptor antibody encephalitis (NMDARE). RESULTS: Forty-four patients (26 females, 18 males, median age 9y 2mo [interquartile range 4y 5mo-11y 8mo], 23 with NMDARE) with a diagnosis of autoimmune encephalitis were included. Postencephalitic epilepsy was more frequent after Ab-negative AE compared to NMDARE (61% vs 14%, p=0.002). Cognitive testing was performed in a subset of patients (n=21; Ab-negative AE=11, NMDARE=10). Full-scale IQ was lower after Ab-negative AE than NMDARE (mean IQ 75 vs 92, p=0.02), primarily because of reduced verbal comprehension index (80 vs 98, p=0.01) and working memory index (77 vs 95, p=0.09). The cognitive function most commonly impaired was executive function (80% [8/10] vs 22% [2/9]). INTERPRETATION: Ab-negative AE was associated with poorer cognitive outcomes than NMDARE at 1-year follow-up. Further studies are required to evaluate if immunotherapy can be optimized to improve outcome.

Mycophenolate mofetil in paediatric autoimmune or immune-mediated diseases of the central nervous system: clinical experience and recommendations.

AIM: To gather data on mycophenolate mofetil (MMF) in paediatric autoimmune/immune-mediated central nervous system (CNS) conditions, focusing on safety and factors that may affect MMF efficacy. METHOD: Retrospective, multicentre study based on four paediatric neurology centres. RESULTS: Forty-four children were included (30 females, 14 males): 19 had proven/suspected autoimmune encephalitis, 14 had inflammatory demyelinating CNS diseases, and 11 had other autoimmune/immune-mediated CNS conditions. Before MMF, all received first-line immune therapies, and 17 had second-line rituximab and/or cyclophosphamide. MMF was started at a median of 9.5 months from disease onset (range 1-127mo) (median age 9y 4mo, range 1y 5mo-16y 5mo), and was used for median 18 months (range 0.3-73mo). On MMF, 31 patients were relapse-free, whereas eight relapsed (excluding patients with chronic-progressive course). Relapses on MMF were associated with medication weaning/cessation, or with suboptimal MMF dosage/duration. Adverse events of MMF occurred in eight patients: six moderate (gastrointestinal, movement disorder, dermatological) and two severe (infectious). INTERPRETATION: MMF use in paediatric neuroimmunology is heterogeneous, although relatively safe. We have identified factors that may affect MMF efficacy and provide recommendations on MMF usage. WHAT THIS PAPER ADDS: Mycophenolate mofetil (MMF) use was heterogeneous with relatively common adverse events, although mostly not severe. MMF treatment reduced median annualized relapse rate, although 20% of patients relapsed on MMF. A high relapse rate pre-MMF and late MMF start were associated with higher probability of relapsing on MMF. Most relapses were associated with suboptimal MMF dosage, short MMF duration, or concurrent medication weaning/discontinuation.

MICOFENOLATO DE MOFETILO EN ENFERMEDADES PEDIÁTRICAS AUTOINMUNES O INMUNO-MEDIADAS DEL SISTEMA NERVIOSO CENTRAL: EXPERIENCIA CLÍNICA Y RECOMENDACIONES: OBJETIVO: Recolectar información sobre el uso de Micofenolato de mofetilo (MMF) en enfermedades pediátricas del sistema nervioso central (SNC) autoinmunes o inmuno-mediadas, focalizando en la seguridad y otros factores que pudieran afectar la eficacia del MMF. MÈTODO: Estudio retrospectivo, multicéntrico, con base en cuatro centros de neurología infantil. RESULTADOS: Se incluyeron 44 niños (30 sexo femenino, 14 masculino): 19 de ellos tuvieron encefalitis autoimmune confirmada / sospechada, 14 tuvieron enfermedades inflamatorias desmielinizantes del SNC y 11 tuvieron otras condiciones autoinmunes o inmuno-mediadas del SNC. Previo al MMF todos recibieron terapias inmunológicas de primera línea, y 17 recibieron como segunda línea rituximab y / o ciclofosfamida. MMF fue iniciada a una mediana de 9.5 meses desde el comienzo de la enfermedad (rango 1-127 meses) (edad mediana 9 años y 4 meses, rango 1 año y 5 meses a 16 años y 5 meses), y fue utilizada por un tiempo mediana de 18 meses (rango 0.3 a 73 meses). Bajo MMF, 31 pacientes estuvieron libres de recidivas, mientras que 8 recidivaron (excluyendo aquellos con un curso crónico-progresivo). Las recaídas bajo el MMF estuvieron asociadas a suspensión/cese, o dosis de MMF o duración de tratamiento subóptimos. En ocho pacientes se observaron reacciones adversas al MMF: seis moderados (gastrointestinales, trastornos de movimiento o dermatológicos) y dos severos (infecciones). INTERPRETACIÓN: El uso de MMF en neuroinmunología pediátrica es heterogéneo, aunque relativamente seguro. Identificamos factores que pueden afectar la eficacia del MMF y proponemos recomendaciones sobre su uso.

MICOFENOLATO MOFETIL EM DOENÇAS PEDIÁTRICAS AUTO-IMUNES OU IMUNO-MEDIADAS DO SISTEMA NERVOSO CENTRAL: EXPERIÊNCIA CLÍNICA E RECOMENDAÇÕES: OBJETIVO: Reunir dados do micofenolato mofetil (MMF) em condições pediátricas auto-imunes ou imuno-mediadas do sistema nervoso central (SNC), com foco na segurança e nos fatores que podem afetar a eficácia do MMF. MÉTODO: Estudo restrospectivo multicêntrico baseado em quatro centros de neurologia pediátrica. RESULTADOS: Quarenta e quatro crianças foram incluídas (30 do sexo feminino, 14 do sexo masculino): 19 tiveram encefalite auto-imune comprovada/suspeita, 14 tiveram doenças inflamatórias desmielinizantes do SNC, e 11 tiveram outras condições auto-imunes ou imuno-mediadas do SNC. Antes do MMF, todas receberam imuno-terapias de primeira linha, e 17 tiveram rituximab e/ou ciclofosfamida de segunda linha. O MMF foi iniciado em uma mediana de 9.5 meses após o início da doença (variação de 1-127 meses) (idade mediana 9a 4m, variação 1a 5m a 16a 5m), e foi utilizado por uma mediana de 18 meses (variação 0.3-73m). Com MMF, 31 pacientes ficaram livres de recidivas, enquanto oito tiveram recidivas (excluídos os pacientes com curso crônico-progressivo). As recidivas com MMF forma associadas com desmame/descontinuidade da medicação, ou com dosagem/duração do MMF sub-ótimas. Efeitos adversos do MMF ocorreram em oito pacientes: seis moderados (gastrointestinal, desordem motora, dermatológico) e dois severos (infeccioso). INTERPRETAÇÃO: O uso de MMF em neuroimunologia pediátrica é heterogêneo, embora relativamente seguro. Identificamos fatores que podem afetar a eficácia do MMF e fornecemos recomendações sobre o uso de MMF.

Utility and safety of plasma exchange in paediatric neuroimmune disorders.

AIM: Our aim was to ascertain the indications, side effects, and outcomes in children receiving therapeutic plasma exchange (TPE) for neurological disorders. METHOD: Medical records were retrospectively reviewed for 58 consecutive children (age ≤16y) undergoing 67 courses of TPE across four tertiary centres. Patient characteristics, treatment schedules, complications, and outcomes were analysed. RESULTS: Median age at initiation of TPE was 9 years (range 1-15y). Indications included peripheral nervous system (PNS; n=18) and central nervous system (CNS; n=40) disorders. Courses comprised a median six exchanges (range 2-179) over 8 days (range 3-466). Forty-two out of 58 (73%) children were severely disabled (bedridden) at initiation and 24 out of 58 (41%) were admitted to intensive care units. Treating clinicians' impression of response was positive in 16 out of 18 of those with PNS disorders versus 22 out of 40 with CNS disorders (p=0.016). Improvements in disability (modified Rankin Scale) occurred in 13 out of 58 (22%) children by completion of TPE (p=0.003). Complications occurred in 40 out of 67 (60%) courses, of which 16 out of 67 (24%) were line related. Potentially life-threatening complications occurred in 2 out of 67 (3%) courses. INTERPRETATION: This cohort study provides safety and efficacy information for clinicians and families and a basis for future prospective studies. WHAT THIS PAPER ADDS: Disability scores for severe neuroimmune disorders remained stable or improved during therapeutic plasma exchange treatment. Complications occurred frequently but were typically mild and correctable.

UTILIDAD Y SEGURIDAD DEL INTERCAMBIO DE PLASMA EN TRASTORNOS NEUROINMUNES PEDIÁTRICOS: OBJETIVO: Nuestro objetivo fue determinar las indicaciones, los efectos secundarios y los resultados en niños que recibieron intercambio terapéutico de plasma (TPE) para trastornos neurológicos. MÉTODO: Se revisaron retrospectivamente los registros médicos de 58 niños consecutivos (≤16 años) que se sometieron a 67 cursos de TPE en cuatro centros terciarios. Se analizaron las características de los pacientes, los esquemas de tratamiento, las complicaciones y los resultados. RESULTADOS: La edad mediana al inicio de la TPE fue de 9 años (rango 1-15 años). Las indicaciones incluían trastornos del sistema nervioso periférico (SNP; n = 18) y del sistema nervioso central (SNC; n = 40). Los cursos comprendieron una mediana de 6 intercambios (rango 2-179) durante 8 días (rango 3-466). Cuarenta y dos de 58 (73%) niños presentaban un grado de discapacidad severa (postrados en cama) al inicio y 24 de 58 (41%) fueron ingresados en unidades de cuidados intensivos. El tratamiento de la impresión de respuesta de los médicos fue positivo en 16 de 18 de las personas con trastornos de SNP versus 22 de 40 en trastornos del SNC (p = 0,016). Las mejoras en la discapacidad (escala de Rankin modificada) se produjeron en 13 de los 58 (22%) niños al completar el TPE (p = 0,003). Las complicaciones ocurrieron en 40 de 67 cursos (60%), de los cuales 16 de 67 (24%) estaban relacionados con la línea. Complicaciones potencialmente peligrosas para la vida ocurrieron en 2 de 67 (3%) cursos. INTERPRETACIÓN: Este estudio de cohorte proporciona información de seguridad y eficacia para profesionales y familiares y una base para futuros estudios prospectivos.

UTILIDADE E SEGURANÇA DA TRANSFERÊNCIA DE PLASMA EM TRANSTORNOS NEUROIMUNES PEDIÁTRICOS: OBJETIVO: Nosso objetivo foi verificar as indicações, efeitos colaterais, e resultados em crianças recebendo transferência terapêutica de plasma (TTP) para transtornos neurológicos. MÉTODO: Registros médicos foram retrospectivamente revisados para 58 crianças (idade ≤16a) passando por 67 cursos de TTP em quatro centros terciários. Características dos pacientes, rotina de tratamento, complicações e resultados foram analisados. RESULTADOS: A idade mediana ao início da TTP foi 9 anos (variação 1-15 anos). Indicações incluíram transtornos do sistema nervoso periférico (SNP; n = 18) e sistema nervoso central (SNC; n = 40) disorders. Os cursos compreenderam uma mediana de seis transferências (variação 2-179) em 8 dias (variação 3-466). Quarenta e duas em 58 (73%) crianças estavam severamente incapacidadas (acamadas) no início e 24 em 58 (41%) foram admitidas em unidades de cuidado intensivo. A impressão de resposta dos clínicos que as tratavam foi positiva em 16 de 18 daquelas com transtornos do SNP versus 22 de 40 daquelas com desordens do SNC (p = 0,016). Melhoras na incapacidade (Escala de Rankin modificada) ocorreram em 13 de 58 (22%) crianças ao final da TTP (p = 0,003). Complicações ocorreram em 40 de 67 (60%) cursos, dos quais 16 em 67 (24%) eram relacionados à linha. Complicações com potencial risco de vida ocorreram em 2 de 67 (3%) cursos. INTERPRETAÇÃO: Este estudo de coorte fornece informação sobre a segurança e eficácia para clínicos e famílias, e uma base para futuros estudos prospectivos.

Systematic review of immunoglobulin use in paediatric neurological and neurodevelopmental disorders.

AIM: A systematic literature review of intravenous immunoglobulin (IVIG) treatment of paediatric neurological conditions was performed to summarize the evidence, provide recommendations, and suggest future research. METHOD: A MEDLINE search for articles reporting on IVIG treatment of paediatric neuroinflammatory, neurodevelopmental, and neurodegenerative conditions published before September 2015, excluding single case reports and those not in English. Owing to heterogeneous outcome measures, meta-analysis was not possible. Findings were combined and evidence graded. RESULTS: Sixty-five studies were analysed. IVIG reduces recovery time in Guillain-Barré syndrome (grade B). IVIG is as effective as corticosteroids in chronic inflammatory demyelinating polyradiculoneuropathy (grade C), and as effective as tacrolimus in Rasmussen syndrome (grade C). IVIG improves recovery in acute disseminated encephalomyelitis (grade C), reduces mortality in acute encephalitis syndrome with myocarditis (grade C), and improves function and stabilizes disease in myasthenia gravis (grade C). IVIG improves outcome in N-methyl-d-aspartate receptor encephalitis (grade C) and opsoclonus-myoclonus syndrome (grade C), reduces cataplexy symptoms in narcolepsy (grade C), speeds recovery in Sydenham chorea (grade C), reduces tics in selected cases of Tourette syndrome (grade D), and improves symptoms in paediatric autoimmune neuropsychiatric disorder associated with streptococcal infection (grade B). INTERPRETATION: IVIG is a useful therapy in selected neurological conditions. Well-designed, prospective, multi-centre studies with standardized outcome measures are required to compare treatments.

N-methyl-d-aspartate (NMDA) receptor antibodies encephalitis mimicking an autistic regression.

Expressive dysphasia and mutism are common clinical features in children and adults with N-methyl-d-aspartate receptor antibodies (NMDAR-Ab) encephalitis, and are likely to result from NMDAR hypofunction. A prodromal loss of social and communication skills can typify that of an autistic regression, particularly when presenting under the age of 3 years. Here we describe two toddlers who presented with developmental regression, particularly of their social communication skills, mimicking an autistic regression, who were found to have NMDAR-Ab in the serum and cerebrospinal fluid. Although both patients had some other neurological features, they were subtle, which resulted in delayed diagnosis of NMDAR-Ab encephalitis. Importantly, immunotherapy was beneficial in both patients, with significant improvement of their language skills and behaviour.

Clinical and radiological features of recurrent demyelination following acute disseminated encephalomyelitis (ADEM).

OBJECTIVE: To identify clinical and radiological features of children that relapse following an initial presentation of acute disseminated encephalomyelitis (ADEM). METHODS: Clinical records and neuroimaging of children under the age of 16 years presenting with ADEM to a pediatric neurology referral center between 2006 and 2010 were evaluated. RESULTS: Of the 32 children with ADEM, 24 (7 female) with a median age of 4.8 (range 3-15) had a monophasic course. Eight patients (25%; 4 female) with median age of 6.9 (range 3-16) had relapsing demyelination; 3 relapsing within the 3 month interval (still defined within a monophasic event); 4 with multiphasic disseminated encephalomyelitis (MDEM), and 1 with non-multiple sclerosis recurrent demyelination. Clinical features at presentation could not distinguish the monophasic from the relapsing group. Infratentorial imaging changes (brain stem and cerebellar) were seen more frequently in the relapsing group (8/8 vs. 20/24), although differences were not statistically significant. At relapse, seven of the eight patients had clinical and radiologic infratentorial syndromes involving brainstem and/or cerebellum. Only one patient had more than one relapse. After a median follow up of 27 months (range 0-96) across the whole group, no patients were diagnosed with multiple sclerosis. CONCLUSIONS: ADEM patients with infratentorial demyelination are more likely to present with a second infratentorial demyelination, although clinical and radiological features at outset could not predict the relapsing cohort.