GABRA1-Related Disorders: From Genetic to Functional Pathways.

OBJECTIVE: Variants in GABRA1 have been associated with a broad epilepsy spectrum, ranging from genetic generalized epilepsies to developmental and epileptic encephalopathies. However, our understanding of what determines the phenotype severity and best treatment options remains inadequate. We therefore aimed to analyze the electroclinical features and the functional effects of GABRA1 variants to establish genotype-phenotype correlations. METHODS: Genetic and electroclinical data of 27 individuals (22 unrelated and 2 families) harboring 20 different GABRA1 variants were collected and accompanied by functional analysis of 19 variants. RESULTS: Individuals in this cohort could be assigned into different clinical subgroups based on the functional effect of their variant and its structural position within the GABRA1 subunit. A homogenous phenotype with mild cognitive impairment and infantile onset epilepsy (focal seizures, fever sensitivity, and electroencephalographic posterior epileptiform discharges) was described for variants in the extracellular domain and the small transmembrane loops. These variants displayed loss-of-function (LoF) effects, and the patients generally had a favorable outcome. A more severe phenotype was associated with variants in the pore-forming transmembrane helices. These variants displayed either gain-of-function (GoF) or LoF effects. GoF variants were associated with severe early onset neurodevelopmental disorders, including early infantile developmental and epileptic encephalopathy. INTERPRETATION: Our data expand the genetic and phenotypic spectrum of GABRA1 epilepsies and permit delineation of specific subphenotypes for LoF and GoF variants, through the heterogeneity of phenotypes and variants. Generally, variants in the transmembrane helices cause more severe phenotypes, in particular GoF variants. These findings establish the basis for a better understanding of the pathomechanism and a precision medicine approach in GABRA1-related disorders. Further studies in larger populations are needed to provide a conclusive genotype-phenotype correlation. ANN NEUROL 2023.

Impact of therapeutic hypothermia on infantile spasms: an observational cohort study.

AIM: To establish the incidence of infantile spasms in children in the southern region of the Republic of Ireland and to compare the incidence of infantile spasms before and after the introduction of therapeutic hypothermia in infants with hypoxic-ischemic encephalopathy (HIE). METHOD: Children born between 2003 and 2015 and diagnosed with infantile spasms (epileptic spasms with or without hypsarrhythmia) in the first 2 years of life were identified through audits of electroencephalography reports and paediatric neurology patient lists. Data on live births were obtained from the regional hospital statistics databases. Medical charts of infantile spasm cases were reviewed for demographic information, diagnostic workup results, treatment response, disease course, and developmental outcome. RESULTS: Forty-two infants with infantile spasms were identified. The cumulative incidence of infantile spasms up to the age of 2 years was 4.01 per 10 000 live births. Difference due to sex was minimal (22 males, 20 females) and most infants were delivered at or near term with gestational ages ranging between 30.0 and 41.8 weeks (median [interquartile range] 39.6wks [38.1-40.0wks]). The aetiology for infantile spasms was identified in almost two-thirds of cases, with HIE being the single most common cause (n=7). Other causes included chromosomal and monogenetic abnormalities (n=8). Infantile spasms occurred in moderate and severe grades of HIE, with a significantly higher incidence in those with severe HIE (p=0.029). Infants with severe HIE who did not receive therapeutic hypothermia were six times more likely to develop infantile spasms compared to those who did, but the difference was not statistically significant (4 out of 16 vs 1 out of 24, p=0.138). INTERPRETATION: This study provides detailed information about infantile spasms before and after the introduction of therapeutic hypothermia. HIE severity is a risk factor for the development of infantile spasms. The introduction of therapeutic hypothermia may have had an impact, but the effect was hard to ascertain in this cohort due to the small number of infants. WHAT THIS PAPER ADDS: The incidence of infantile spasms and patient characteristics in the southern region of the Republic of Ireland is similar to internationally published data. None of the infants with a history of mild hypoxic-ischemic encephalopathy (HIE) developed infantile spasms. The risk of infantile spasms was higher in infants with severe HIE. Infantile spasms were more frequent in infants with severe HIE not treated with therapeutic hypothermia.

IMPACTO DE LA HIPOTERMIA COMO TRATAMIENTO EN LOS ESPASMOS INFANTILES: UN ESTUDIO DE COHORTE OBSERVACIONAL: OBJETIVO: Establecer la incidencia de los espasmos infantiles en niños de la República de Irlanda y comparar la incidencia de los espasmos infantiles antes y después de la introducción de la hipotermia terapéutica en niños con encefalopatía hipóxico-isquémica (EHI). MÉTODO: Niños nacidos entre 2003 y 2015 y diagnosticados con espasmos infantiles (espasmos epilépticos con o sin hipsarritmia) en los primeros 2 años de vida fueron identificados por medio de auditorías de reportes de electroencefalográficos y listas de pacientes de neurólogos infantiles. Datos sobre los nacidos vivos se obtuvieron de la base de datos estadística del hospital regional. Las historias clínicas de los casos de espasmos infantiles fueron revisadas para obtener datos demográficos, resultados diagnósticos, respuesta a tratamiento, curso de la enfermedad y resultados del desarrollo. RESULTADOS: Fueron identificados 42 niños con espasmos infantiles. La incidencia acumulada de los espasmos infantiles por encima de los 2 años fue de 4,01 por 10.000 nacidos vivos. La diferencia debida al sexo fue mínima (22 masculinos, 20 femeninos) y la mayoría nacieron en o cercano a término, con edad gestacional entre 30,0 y 41,8 semanas (media (rango Intercuartil) 39,6 semanas (38,1-40,0 semanas). La etiología de espasmos infantiles fue identificada en dos tercios de los casos, siendo EHI la causa más común (7 de 42). Otras causas incluyeron anormalidades cromosómicas y monogénicas (8 de 42). Los espasmos infantiles ocurrieron en los grados moderados y severos de EHI con incidencia significativamente mayor en aquellos casos severos de EHI (p=0,029). Los niños con EHI severo que no recibieron hipotermia terapéutica tuvieron una probabilidad seis veces mayor de desarrollar espasmos infantiles comparados con aquellos quienes la recibieron, pero la diferencia no era estadísticamente significativa (4 de 16 vs 1 de 14, p=0,138). INTERPRETACIÓN: Este estudio proporciona información detallada acerca de los espasmos infantiles antes y después de la introducción de la hipotermia terapéutica. La severidad de la EHI es un factor de riesgo para el desarrollo de los espasmos infantiles. La introducción de la hipotermia terapéutica puede haber tenido un impacto, pero el efecto fue difícil de determinar en esta cohorte debido al pequeño número de recién nacidos.

IMPACTO DA HIPOTERMIA TERAPÊUTICA NOS ESPASMOS INFANTIS: UM ESTUDO DE COORTE OBSERVACIONAL: OBJETIVO: Estabelecer a incidência de espasmos infantis em crianças da República da Irlanda e comparar a incidência de espasmos infantis antes e após a introdução da hipotermia terapêutica em lactentes com encefalopatia hipóxica-isquêmica (EHI). MÉTODO: Crianças nascidas entre 2003 e 2015 e diagnosticadas com espasmos infantis (espasmos epilépticos com ou sem hipsarritmia) nos primeiros 2 anos de vida foram identificadas por meio de checagem dos relatórios de eletroencefalografia e listas de pacientes de neurologia pediátrica. Dados sobre nascidos vivos foram obtidos nas bases de dados estatísticas dos hospitais regionais. Prontuários médicos sobre casos de espasmos infantis foram revisados quanto a dados demográficos, resultados diagnósticos, resposta ao tratamento, curso da doença, e resultado desenvolvimental. RESULTADOS: Quarenta e dois lactentes com espasmos infantis foram identificados. A incidência cumulativa de espasmos infantis até os dois anos de idade foi 4,01 por 10.000 nascidos vidos. Diferenças devida ao sexo foram mínimas (22 meninos, 20 meninas) e a maior parte dos lactentes nasceu próximo ao termo, com idades gestacionais variando de 30,0 41,8 semanas (mediana [intervalo interquartil] 39,6 sem [38,1-40,0sem]). A etiologia dos espasmos infantis foi identificada em dois terços dos casos, com a EHI sendo a causa mais comum (7 em cada 42). Outras causas incluíram anormalidades cromossômicas e monogenéticas (8 em 42). Os espasmos infantis aconteceram em graus moderados a severos de EHI, com incidência significantemente maior naqueles com EHI severa (p=0,029). Lactentes com EHI severa que não receberam hipotermia terapêutica tinham seis vezes mais probabilidade de desenvolver espasmos infantis comparados com os que receberam, mas a diferença não foi estatisticamente significativa. (4 em16 vs 1 em 24, p=0,138). INTERPRETAÇÃO: Este esudo fornece informação detalhada sobre espasmos infantis antes e após a introdução de hipotermia terapêutica. A severidade da EHI é um fator de risco para o desenvolvimento de espasmos infantis. A introdução de hiportermia terapêutica por ter tido um impacto, mas o efeito foi difícil de assegurar nesta coorte devido ao pequeno número de lactentes.

Subarachnoid and parenchymal haemorrhages as a complication of severe diabetic ketoacidosis in a preadolescent with new onset type 1 diabetes.

Diabetic ketoacidosis (DKA) is one of the most common causes of morbidity and mortality in new onset type 1 diabetes mellitus (T1DM). Children have a higher rate of neurological complications from DKA when compared to adults. The differential for sudden focal neurological deterioration in the setting of DKA is cerebral oedema followed by ischaemic and haemorrhagic stroke. Spontaneous intracranial haemorrhages can present with non-specific features frequently, for example, impaired consciousness, even when biochemical parameters are improving in the setting of DKA. We report the case of a girl with new onset T1D who presented in severe DKA and subsequently developed intracerebral parenchymal and subarachnoid haemorrhages. Our patient is unique in that no focal neurological or neuropsychological deficits have been found at 1-year follow up, compared to the literature which suggests poor outcomes. Our case contrasts with these previous cases as none of the other case reports demonstrated subarachnoid haemorrhages with survival.

Electroencephalography Quality and Application Times in a Pediatric Emergency Department Setting: A Feasibility Study.

BACKGROUND: Status epilepticus is the most common neurological emergency presenting to pediatric emergency departments. Nonconvulsive status epilepticus can be extremely challenging to diagnose, however, requiring electroencephalographic (EEG) confirmation for definitive diagnosis. We aimed to determine the feasibility of achieving a good-quality pediatric EEG recording within 20 minutes of presentation to the emergency department. METHODS: Single-center prospective feasibility study in Cork University Hospital, Ireland, between July 2021 and June 2022. Two-channel continuous EEG was recorded from children (1) aged <16 years and (2) with Glasgow Coma Scale <11 or a reduction in baseline Glasgow Coma Scale in the case of a child with a neurodisability. RESULTS: Twenty patients were included. The median age at presentation was 65.8 months (interquartile range, 23.2 to 119.0); 50% had a background diagnosis of epilepsy. The most common reason for EEG monitoring was status epilepticus (85%) followed by suspected nonconvulsive status (10%) and reduced consciousness of unknown etiology (5%). The mean length of recording was 93.1 minutes (S.D. 47.4). The mean time to application was 41.3 minutes (S.D. 11.7). The mean percent of artifact in all recordings was 19.3% (S.D. 15.9). Thirteen (65%) EEGs had <25% artifact. Artifact was higher in cases in which active airway management was ongoing. CONCLUSIONS: EEG monitoring can be achieved in a pediatric emergency department setting within one hour of presentation. Overall, artifact percentage was low outside of periods of airway manipulation. Future studies are required to determine its use in early seizure detection and its support role in clinical decision-making in these patients.

Neonatal stroke surveillance study protocol in the United Kingdom and Republic of Ireland.

Neonatal stroke is a devastating condition that causes brain injury in babies and often leads to lifelong neurological impairment. Recent prospective population studies of neonatal stroke are lacking. Neonatal strokes are different from those in older children and adults. A better understanding of its aetiology, current management, and outcomes could reduce the burden of this rare condition. The study aims to explore the incidence and 2 year outcomes of neonatal stroke across an entire population in the UK and Republic of Ireland. This is an active national surveillance study using a purpose-built integrated case notification-data collection online platform. Over a 13 month period, with a potential 6 month extension, clinicians will notify neonatal stroke cases presenting in the first 90 days of life electronically via the online platform monthly. Clinicians will complete a primary questionnaire via the platform detailing clinical information, including neuroimaging, for analysis and classification. An outcome questionnaire will be sent at 2 years of age via the platform. Appropriate ethics and regulatory approvals have been received. The neonatal stroke study represents the first multinational population surveillance study delivered via a purpose-built integrated case notification-data collection online platform and data safe haven, overcoming the challenges of setting up the study.

Case Report: Early Neonatal EEG in Two Infants with Pallister Killian Syndrome (PKS).

Pallister Killian Syndrome (PKS) is a rare genetic disorder caused by a mosaic tetrasomy of the short arm of chromosome 12. The syndrome is characterised by typical craniofacial dysmorphism, congenital anomalies and intellectual disability. Epilepsy is a known complication, with onset usually occurring in early childhood and characterised most commonly by spasms and myoclonic seizures. To the best of our knowledge, there have been no cases describing the early neonatal EEG in PKS and  electrographic seizures, to date. Here, we report two cases of PKS presenting in the neonatal period with distinctive EEG features and seizures.

Low excretor glutaric aciduria type 1 of insidious onset with dystonia and atypical clinical features, a diagnostic dilemma.

A 4-year-old girl was referred for reassessment of dyskinetic cerebral palsy. Initial investigations in her country of birth, India, had not yielded a diagnosis. MRI brain in infancy revealed bilateral putamen hyperintensity. She had generalized dyskinesia predominantly bulbar and limbs. Motor and speech development were most affected with preservation of cognitive development. There was no history of acute encephalopathic crisis or status dystonicus. Initial urine organic acids and amino acids and acylcarnitine profile (ACP) were normal. A dystonia genetic panel showed compound heterozygosity with a pathogenic variant and a variant of uncertain significance in the GCDH gene. The latter is hitherto undescribed and is indicative of a potential diagnosis of glutaric aciduria type 1 (alternatively glutaric acidemia type 1) (GA-1), an autosomal recessive disorder of mitochondrial lysine/hydroxylysine and tryptophan metabolism. Repeat urine organic acids showed isolated slightly increased 3-hydroxy glutarate excretion consistent with GA-1 and characterizing the patient as a "low excretor," a diagnostic sub-group where diagnosis is more challenging but prognosis is similar. Repeat MRI Brain at age 4 showed volume loss and symmetric T2 hyperintensity in the posterior putamina bilaterally. This case highlights the diagnostic dilemma of GA-1 where differing clinical courses, genetic variants, neuroradiological findings, and biochemical excretion patterns may lead to a later diagnosis. The presence of newborn screening for GA-1 should not dull the clinician's suspicion of the possibility that GA-1 may present with a complex movement disorder. Timely diagnosis and treatment is essential, as neurological sequelae are largely irreversible.

Case Report: Electroencephalography in a neonate with isolated sulfite oxidase deficiency - a case report and literature review.

Isolated sulfite oxidase deficiency (ISOD) is a rare autosomal recessive neuro-metabolic disorder caused by a mutation in the sulfite oxidase (SUOX) gene situated on chromosome 12. Due to the deficiency of this mitochondrial enzyme (sulfite oxidase), the oxidative degradation of toxic sulfites is disrupted. The most common form of this disease has an early onset (classical ISOD) in the neonatal period, with hypotonia, poor feeding and intractable seizures, mimicking hypoxic-ischaemic encephalopathy. The evolution is rapidly progressive to severe developmental delay, microcephaly and early death. Unfortunately, there is no effective treatment and the prognosis is very poor. In this article, we described the evolution of early continuous electroencephalography (EEG) in a case of ISOD with neonatal onset, as severely encephalopathic background, with refractory seizures and distinct delta-beta complexes. The presence of the delta-beta complexes might be a diagnostic marker in ISOD. We also performed a literature review of published cases of neonatal ISOD that included EEG monitoring.

Childhood optic neuritis clinical features and outcome.

AIM: To describe clinical features and outcome of a series of children with first-episode optic neuritis investigated in three paediatric neurology centres. METHODS: Databases were searched to identify children (<16 years) with optic neuritis and life table analysis was used. RESULTS: 44 children (female/male ratio 1.8) median age 10.9 years were followed up for median 1 year. Optic neuritis was unilateral in 43%. Maximal visual deficit was severe (<6/60) in 77%, with full recovery in 70%. Cumulative probability of developing MS (11/44) or NMO (3/44) at 2 years was 0.45. Relapsing optic neuritis was a strong predictor for development of MS or NMO. A positive MRI (>1 brain T2 hyperintense lesion) was a strong predictor for development of MS. DISCUSSION: Childhood optic neuritis is associated with severe visual deficit with good recovery. An initial abnormal MRI brain scan or relapsing optic neuritis should alert the clinician to MS or NMO diagnosis.

Clinical neuroimaging features and outcome in molybdenum cofactor deficiency.

Molybdenum cofactor deficiency predominantly affects the central nervous system. There are limited data on long-term outcome or brain magnetic resonance imaging (MRI) features. We examined the clinical, brain MRI, biochemical, genetic, and electroencephalographic features and outcome in 8 children with a diagnosis of molybdenum cofactor deficiency observed in our institution over 10 years. Two modes of presentation were identified: early (classical) onset with predominantly epileptic encephalopathy in 6 neonates, and late (atypical) with global developmental impairment in 2 children. Children in both groups had varying degrees of motor, language, and visual impairment. There were no deaths. Brain MRI demonstrated cerebral infarction in all but one child in the atypical group. Distinctive features were best observed on early brain MRI: acute symmetrical involvement of the globus pallidi and subthalamic regions coexisting with older cerebral hemisphere infarction, chronic lesions suggestive of a prenatal insult, pontocerebellar hypoplasia with retrocerebellar cyst, and presence of a distinctive band at the cortical/subcortical white matter. Sequential imaging revealed progressive pontine atrophy and enlargement of retrocerebellar cyst. The brain MRI of one child with atypical presentation (verbal dyspraxia, lens dislocation) showed symmetrical cerebellar deep nuclei signal abnormality without cerebral infarction. Imaging pattern on early brain MRI (<1 week) may prompt the diagnosis, potentially allowing early treatment and disease modifications.

Perinatal dyskinesia as a presenting feature in Prader Willi syndrome.

Prader Willi Syndrome (PWS) is a complex genetic disorder. Infants present with hypotonia and feeding difficulties, usually without respiratory symptoms, but with distinctive facial features. Early neonatal diagnosis can however be difficult in children with only subtle distinctive appearances or with atypical clinical signs, leading to a significant delay in the diagnosis. To highlight the diagnostic difficulties we reviewed our experience of infants with PWS referred to our tertiary centre. We describe 14 patients, 10 of whom presented in the neonatal period. All had axial hypotonia, and poor feeding. Twelve had a paucity of movement, 11 had distinctive features and 10 had a reduced level of alertness in the neonatal period. In addition to these typical features, four patients had prominent limb dyskinesia, which has only been reported once before in infants with PWS. We draw attention to this relatively common but poorly acknowledged sign that can be seen at presentation of PWS.