The emerging spectrum of fetal acetylcholine receptor antibody-related disorders (FARAD).

In utero exposure to maternal antibodies targeting the fetal acetylcholine receptor isoform (fAChR) can impair fetal movement, leading to arthrogryposis multiplex congenita (AMC). Fetal AChR antibodies have also been implicated in apparently rare, milder myopathic presentations termed fetal acetylcholine receptor inactivation syndrome (FARIS). The full spectrum associated with fAChR antibodies is still poorly understood. Moreover, since some mothers have no myasthenic symptoms, the condition is likely underreported, resulting in failure to implement effective preventive strategies. Here we report clinical and immunological data from a multicentre cohort (n = 46 cases) associated with maternal fAChR antibodies, including 29 novel and 17 previously reported with novel follow-up data. Remarkably, in 50% of mothers there was no previously established myasthenia gravis (MG) diagnosis. All mothers (n = 30) had AChR antibodies and, when tested, binding to fAChR was often much greater than that to the adult AChR isoform. Offspring death occurred in 11/46 (23.9%) cases, mainly antenatally due to termination of pregnancy prompted by severe AMC (7/46, 15.2%), or during early infancy, mainly from respiratory failure (4/46, 8.7%). Weakness, contractures, bulbar and respiratory involvement were prominent early in life, but improved gradually over time. Facial (25/34; 73.5%) and variable peripheral weakness (14/32; 43.8%), velopharyngeal insufficiency (18/24; 75%) and feeding difficulties (16/36; 44.4%) were the most common sequelae in long-term survivors. Other unexpected features included hearing loss (12/32; 37.5%), diaphragmatic paresis (5/35; 14.3%), CNS involvement (7/40; 17.5%) and pyloric stenosis (3/37; 8.1%). Oral salbutamol used empirically in 16/37 (43.2%) offspring resulted in symptom improvement in 13/16 (81.3%). Combining our series with all previously published cases, we identified 21/85 mothers treated with variable combinations of immunotherapies (corticosteroids/intravenous immunoglobulin/plasmapheresis) during pregnancy either for maternal MG symptom control (12/21 cases) or for fetal protection (9/21 cases). Compared to untreated pregnancies (64/85), maternal treatment resulted in a significant reduction in offspring deaths (P < 0.05) and other complications, with treatment approaches involving intravenous immunoglobulin/ plasmapheresis administered early in pregnancy most effective. We conclude that presentations due to in utero exposure to maternal (fetal) AChR antibodies are more common than currently recognized and may mimic a wide range of neuromuscular disorders. Considering the wide clinical spectrum and likely diversity of underlying mechanisms, we propose 'fetal acetylcholine receptor antibody-related disorders' (FARAD) as the most accurate term for these presentations. FARAD is vitally important to recognize, to institute appropriate management strategies for affected offspring and to improve outcomes in future pregnancies. Oral salbutamol is a symptomatic treatment option in survivors.

The 2017 and 2022 ILAE epilepsy classification systems identify needs and opportunities in care: A paediatric hospital-based study.

OBJECTIVES: There is a paucity of studies reporting the epilepsy spectrum using the 2017 and 2022 ILAE classification systems in everyday clinical practice. To identify gaps and opportunities in care we evaluated a hospital-based cohort applying these epilepsy classification systems, including aetiology and co-morbidity, and the utility of molecular genetic diagnosis to identify available precision therapies. METHODS: Cross sectional retrospective study of all children with epilepsy (≤16 years) attending University Hospital Galway (2017-2022). Data collection and analysis of each case was standardised to ensure a systematic approach and application of the recent ILAE categorisation and terminology (2017 and 2022). Ethics approval was obtained. RESULTS: Among 356 children, epilepsy was classified as focal (46.1 %), generalised (38.8 %), combined (6.2 %), and unknown (9 %). Epilepsy syndrome was determined in 145/356 (40.7 %), comprising 24 different syndromes, most commonly SeLECTS (9 %), CAE (7 %), JAE (6.2 %) and IESS (5.9 %). New aetiology-specific syndromes were identified (e.g. CDKL5-DEE). Molecular diagnosis was confirmed in 19.9 % (n = 71) which encompassed monogenic (13.8 %) and chromosomopathy/CNV (6.2 %). There was an additional 35.7 % (n = 127) of patients who had a presumed genetic aetiology of epilepsy. Remaining aetiology included structural (18.8 %, n = 67), infectious (2 %, n = 7), metabolic (1.7 %, n = 6) and unknown (30.3 %, n = 108). Encephalopathy categorisation was determined in 182 patients (DE in 38.8 %; DEE in a further 11.8 %) associated with a range of co-morbidities categorised as global delay (29.2 %, n = 104), severe neurological impairment (16.3 %, n = 58), and ASD (14.6 %, n = 52). Molecular-based "precision therapy" was deemed available in 21/356 (5.9 %) patients, with "molecular precision" approach utilised in 13/356 (3.7 %), and some benefit noted in 6/356 (1.7 %) of overall cohort or 6/71 (8.5 %) of the molecular cohort. CONCLUSION: Applying the latest ILAE epilepsy classification systems allow comparison across settings and identifies a major neuro-developmental co-morbidity rate and a large genetic aetiology. We identified very few meaningful molecular-based disease modifying "precision therapies". There is a monumental gap between aetiological identification, and impact of meaningful therapies, thus the new 2017/2022 classification clearly identifies the major challenges in the provision of routine epilepsy care.

Response to treatment and outcomes of infantile spasms in Down syndrome.

AIM: To estimate the prevalence, and evaluate presentation, treatment response, treatment side effects, and long-term seizure outcomes in all known cases of children with Down syndrome and infantile spasms on the island of Ireland. METHOD: This was a 10-year retrospective multicentre review of clinical records and investigations, focusing on treatment response, side effects, and long-term outcomes. RESULTS: The prevalence of infantile spasms in Down syndrome was 3.0% during the study period. Fifty-four infants were identified with median age of spasm onset at 201 days (interquartile range [IQR] 156-242). Spasm cessation was achieved in 88% (n=46) at a median of 110 days (IQR 5-66). The most common first-line medications were prednisolone (n=20, 37%), vigabatrin (n=18, 33.3%), and sodium valproate (n=9, 16.7%). At follow-up (median age 23.7mo; IQR 13.4-40.6), 25% had ongoing seizures and 85% had developmental concerns. Treatment within 60 days did not correlate with spasm cessation. Seventeen children (31%) experienced medication side effects, with vigabatrin accounting for 52%. INTERPRETATION: Prednisolone is an effective and well-tolerated medication for treating infantile spasms in Down syndrome. Despite the high percentage of spasm cessation, developmental concerns and ongoing seizures were common.

Delineating the molecular and phenotypic spectrum of the SETD1B-related syndrome.

PURPOSE: Pathogenic variants in SETD1B have been associated with a syndromic neurodevelopmental disorder including intellectual disability, language delay, and seizures. To date, clinical features have been described for 11 patients with (likely) pathogenic SETD1B sequence variants. This study aims to further delineate the spectrum of the SETD1B-related syndrome based on characterizing an expanded patient cohort. METHODS: We perform an in-depth clinical characterization of a cohort of 36 unpublished individuals with SETD1B sequence variants, describing their molecular and phenotypic spectrum. Selected variants were functionally tested using in vitro and genome-wide methylation assays. RESULTS: Our data present evidence for a loss-of-function mechanism of SETD1B variants, resulting in a core clinical phenotype of global developmental delay, language delay including regression, intellectual disability, autism and other behavioral issues, and variable epilepsy phenotypes. Developmental delay appeared to precede seizure onset, suggesting SETD1B dysfunction impacts physiological neurodevelopment even in the absence of epileptic activity. Males are significantly overrepresented and more severely affected, and we speculate that sex-linked traits could affect susceptibility to penetrance and the clinical spectrum of SETD1B variants. CONCLUSION: Insights from this extensive cohort will facilitate the counseling regarding the molecular and phenotypic landscape of newly diagnosed patients with the SETD1B-related syndrome.

Journal club: old tricks and fresh approaches.

Journal club is a long-standing pedagogy within clinical practice and education. While journal clubs throughout the world traditionally follow an established format, new approaches have emerged in recent times, including learner-centred and digital approaches. Key factors to journal club success include an awareness of the learning goals of the target audience, judicious article selection and emphasis on promoting the engagement of participant learners. This article reviews the role that journal club plays in modern clinical education and considers how to optimise its benefit for contemporary learners.

Clinical spectrum and genotype-phenotype associations of KCNA2-related encephalopathies.

Recently, de novo mutations in the gene KCNA2, causing either a dominant-negative loss-of-function or a gain-of-function of the voltage-gated K+ channel Kv1.2, were described to cause a new molecular entity within the epileptic encephalopathies. Here, we report a cohort of 23 patients (eight previously described) with epileptic encephalopathy carrying either novel or known KCNA2 mutations, with the aim to detail the clinical phenotype associated with each of them, to characterize the functional effects of the newly identified mutations, and to assess genotype-phenotype associations. We identified five novel and confirmed six known mutations, three of which recurred in three, five and seven patients, respectively. Ten mutations were missense and one was a truncation mutation; de novo occurrence could be shown in 20 patients. Functional studies using a Xenopus oocyte two-microelectrode voltage clamp system revealed mutations with only loss-of-function effects (mostly dominant-negative current amplitude reduction) in eight patients or only gain-of-function effects (hyperpolarizing shift of voltage-dependent activation, increased amplitude) in nine patients. In six patients, the gain-of-function was diminished by an additional loss-of-function (gain-and loss-of-function) due to a hyperpolarizing shift of voltage-dependent activation combined with either decreased amplitudes or an additional hyperpolarizing shift of the inactivation curve. These electrophysiological findings correlated with distinct phenotypic features. The main differences were (i) predominant focal (loss-of-function) versus generalized (gain-of-function) seizures and corresponding epileptic discharges with prominent sleep activation in most cases with loss-of-function mutations; (ii) more severe epilepsy, developmental problems and ataxia, and atrophy of the cerebellum or even the whole brain in about half of the patients with gain-of-function mutations; and (iii) most severe early-onset phenotypes, occasionally with neonatal onset epilepsy and developmental impairment, as well as generalized and focal seizures and EEG abnormalities for patients with gain- and loss-of-function mutations. Our study thus indicates well represented genotype-phenotype associations between three subgroups of patients with KCNA2 encephalopathy according to the electrophysiological features of the mutations.

Status dystonicus in childhood.

PURPOSE OF REVIEW: Dystonia is a common paediatric neurological condition. At its most severe, dystonia may lead to life-threatening complications, a state termed status dystonicus. This review provides an update on the definition, causes, management and outcome of childhood status dystonicus. RECENT FINDINGS: High-quality studies in childhood status dystonicus are lacking, though an increasing number of case series have been published. Status dystonicus appears to occur more frequently in children compared with adults, with a clear precipitant identified in around two-thirds of cases. Although febrile illness remains the commonest trigger for status dystonicus, unplanned interruption to deep brain stimulation (DBS) is increasingly reported as a precipitant. In parallel with this, neurosurgical intervention for status dystonicus appears to have become more widely used, though optimum timing and patient selection remains unclear. In most cases, a multistaged approach is required; we propose an 'ABCD' approach - Addressing precipitants, Beginning supportive measures, Calibrating sedation and Dystonia specific medications. Outcomes following status dystonicus appear to have slightly improved in recent years, potentially as a consequence of increasing use of DBS, though mortality has remained around 10%. SUMMARY: Future work is needed to inform evidence-based guidelines for the management of status dystonicus. One of many pressing questions is the precise indication, and timing of interventions such as DBS.

Novel European SLC1A4 variant: infantile spasms and population ancestry analysis.

SLC1A4 deficiency is a recently described neurodevelopmental disorder associated with microcephaly, global developmental delay, abnormal myelination, thin corpus callosum and seizures. It has been mainly reported in the Ashkenazi-Jewish population with affected individuals homozygous for the p.Glu256Lys variant. Exome sequencing performed in an Irish proband identified a novel homozygous nonsense SLC1A4 variant [p.Trp453*], confirming a second case of SLC1A4-associated infantile spasms. As this is the first European identified, population ancestry analysis of the Exome Aggregation Consortium database was performed to determine the wider ethnic background of SLC1A4 deficiency carriers. p.Glu256Lys was found in Hispanic and South Asian populations. Other potential disease-causing variants were also identified. Investigation for SLC1A4 deficiency should be performed regardless of ethnicity and extend to include unexplained early-onset epileptic encephalopathy.

Unexplained early onset epileptic encephalopathy: Exome screening and phenotype expansion.

Early onset epileptic encephalopathies (EOEEs) represent a significant diagnostic challenge. Newer genomic approaches have begun to elucidate an increasing number of responsible single genes as well as emerging diagnostic strategies. In this single-center study, we aimed to investigate a cohort of children with unexplained EOEE. We performed whole-exome sequencing (WES), targeting a list of 137 epilepsy-associated genes on 50 children with unexplained EOEE. We characterized all phenotypes in detail and classified children according to known electroclinical syndromes where possible. Infants with previous genetic diagnoses, causative brain malformations, or inborn errors of metabolism were excluded. We identified disease-causing variants in 11 children (22%) in the following genes: STXBP1 (n = 3), KCNB1 (n = 2), KCNT1, SCN1A, SCN2A, GRIN2A, DNM1, and KCNA2. We also identified two further variants (in GRIA3 and CPA6) in two children requiring further investigation. Eleven variants were de novo, and in one paternal testing was not possible. Phenotypes were broadened for some variants identified. This study demonstrates that WES is a clinically useful screening tool for previously investigated unexplained EOEE and allows for reanalysis of data as new genes are being discovered. Detailed phenotyping allows for expansion of specific gene disorders leading to epileptic encephalopathy and emerging sub-phenotypes.

De novo interstitial deletion 2q14.1q22.1: is there a recognizable phenotype?

In this report we describe a male patient with a rare de novo interstitial deletion of chromosome 2q14.1-q22.1. His karyotype was reported as 46,XY,del(2)(q13q21) but subsequent array comparative genomic hybridization (array CGH) analysis redefined the deletion breakpoints as 2q14.1 and 2q22.1. Eight patients have been reported with deletions either within or spanning the region 2q13 or 2q14 to 2q22.1. In five patients the diagnosis was made by karyotype analysis alone and in three reported patients and the proband array CGH analysis was also performed. When the proband was compared with the eight previously reported patients it was apparent that they shared many clinical findings suggesting that patients with a de novo interstitial deletion involving 2q13 or 2q14 to 2q21 or 2q22 may have a recognizable phenotype. There are 14 known disease-associated genes in the deleted region of 2q14.1-q22.1 and their possible phenotypic effects on the proband and the eight previously reported patients are discussed.

The variable phenotypes of KCNQ-related epilepsy.

Mutations in KCNQ2 and KCNQ3 were originally described in infants with benign familial neonatal seizures (BFNS). Recently, KCNQ2 mutations have also been shown to cause epileptic encephalopathy. This report describes three infants carrying abnormalities of KCNQ2 and one infant with a KCNQ3 mutation. The different KCNQ2 abnormalities led to different phenotypes and included a novel intragenic duplication, c.419_430dup, in an infant with BFNS, a 0.761Mb 20q13.3 contiguous gene deletion in an infant with seizures at 3 months, and a recurrent de novo missense mutation c.881C>T in a neonate with "KCNQ2-encephalopathy." The mutation in KCNQ3, c.989G>A, was novel and occurred in an infant with BFNS. KCNQ-related seizures often present with tonic/clonic manifestations, cyanosis, or apnea. Certain genotype-phenotype correlations help predict outcome. Similarly affected family members suggests benign familial "KCNQ-related" epilepsy, whereas neonatal seizures with unexplained multifocal epileptiform discharges or burst suppression on electroencephalography, and acute abnormalities of the basal ganglia/thalami are suggestive of KCNQ2-encephalopathy, which is often sporadic. 20q13.33 contiguous gene deletion encompassing KCNQ2 may harbor atypical features depending on deletion size. Although the phenotype often guides direct targeted gene testing in these conditions, array CGH should also be considered in suspected sporadic or atypical familial cases to diagnose 20q13.33 deletion.

Status dystonicus: a practice guide.

Status dystonicus is a rare, but life-threatening movement disorder emergency. Urgent assessment is required and management is tailored to patient characteristics and complications. The use of dystonia action plans and early recognition of worsening dystonia may potentially facilitate intervention or prevent progression to status dystonicus. However, for established status dystonicus, rapidly deployed temporizing measures and different depths of sedation in an intensive care unit or high dependency unit are the most immediate and effective modalities for abating life-threatening spasms, while dystonia-specific treatment takes effect. If refractory status dystonicus persists despite orally active anti-dystonia drugs and unsuccessful weaning from sedative or anaesthetic agents, early consideration of intrathecal baclofen or deep brain stimulation is required. During status dystonicus, precise documentation of dystonia sites and severity as well as the baseline clinical state, using rating scales and videos is recommended. Further published descriptions of the clinical nature, timing of evolution, resolution, and epidemiology of status dystonicus are essential for a better collective understanding of this poorly understood heterogeneous emergency. In this review, we provide an overview of the clinical presentation and suggest a management approach for status dystonicus.

Epileptic dyskinetic encephalopathy in KBG syndrome: Expansion of the phenotype.

KBG syndrome is characterised by developmental delay, dental (macrodontia of upper central incisors), craniofacial and skeletal anomalies. Since the identification of variants in the gene (ANKRD11) responsible for KBG syndrome, wider phenotypes are emerging. While there is phenotypic variability within many features of KBG syndrome, epilepsy is not usually markedly severe and movement disorders largely undocumented. Here we describe a novel early onset phenotype of dyskinetic epileptic encephalopathy in a male, who presented during infancy with a florid hyperkinetic movement disorder and developmental regression. Initially he had epileptic spasms and tonic seizures, and EEGs revealed a modified hypsarrhythmia. The epilepsy phenotype evolved to Lennox-Gastaut syndrome with seizures resistant to multiple anti-seizure therapies and the movement disorder evolved to choreoathetosis of limbs and head with oro-lingual dyskinesias. Previous extensive neurometabolic and imaging investigations, including panel-based exome sequencing were unremarkable. Later trio exome sequencing identified a de novo pathogenic heterozygous frameshift deletion of ANKRD11 (c.6792delC; p.Ala2265Profs*72). Review of the literature did not identify any individuals with such a hyperkinetic movement disorder presentation in combination with early-onset epileptic encephalopathy. This report expands the phenotype of ANKRD11-related KBG syndrome to include epileptic dyskinetic encephalopathy.

Abnormal liver function tests and improved survival in a child with splice mutation TARP syndrome.

TARP (talipes equinovarus, atrial septal defect (ASD), Robin sequence, persistent left superior vena cava) syndrome is a rare X-linked disorder affecting the RBM10 gene. It was previously viewed as universally fatal in the early neonatal period, however, recent cases have shown patients surviving beyond this stage. We present a male toddler diagnosed with TARP syndrome due to a a previously unreported splicing mutation c.2295+1G>A in the RBM10 gene. At birth, he had an ASD and Robin sequence, two of the eponymous features, as well as other associated phenotypic features. During infancy, he had an extremely high alpha-fetoprotein, conjugated hyperbilirubinaemia and thrombocytopaenia, features not previously described in TARP syndrome. We discuss these findings as well as our patient's survival past the neonatal period with special consideration to recent genotype-phenotypes correlations.

The changing face of reported status dystonicus - A systematic review.

BACKGROUND: Status Dystonicus (SD) represents the most severe end of the spectrum of dystonia. We aimed to explore whether reported features of cases of SD have changed over time. METHODS: A systematic review of cases of SD reported from 2017 to 2023 and comparison of features to data extracted from 2 previous literature reviews (epochs 2012-2017 and pre-2012). RESULTS: From 53 papers, a total 206 SD episodes in 168 patients were identified from 2017 to 2023. Combining data from all 3 epochs, a total of 339 SD episodes were reported from 277 patients. SD episodes occurred mostly in children, with a trigger identified in 63.4% of episodes, most commonly infection/inflammation. Most reported underlying aetiologies were genetic (e.g. 49.5% between 2017 and 2023), including new associated aetiologies in each epoch. Deep Brain Stimulation (DBS)-related SD increased over time. Neurosurgical interventions were more frequently reported in later epochs. Across the epochs, return to or improvement post SD episode, compared to baseline was reported above 70%. Reported mortality was 4.9% most recently, compared to 11.4% and 7.9%, previously. CONCLUSIONS: SD episodes reported have more than doubled in the last 5 years. Reports of medication change-induced SD have become less frequent, whilst episodes of DBS-related SD have become more frequent. More dystonia aetiologies, including novel aetiologies have been reported in recent cohorts, reflecting advances in genetic diagnosis. Neurosurgical interventions are increasingly reported in the management of SD episodes, including novel use of intraventricular baclofen. Overall outcomes from SD remain largely unchanged over time. No prospective epidemiological studies of SD were identified.

Generation of three induced pluripotent stem cell lines from a patient with KCNQ2 developmental and epileptic encephalopathy as a result of the pathogenic variant c.638C > T; p.Arg213Gln (NUIGi063-A, NUIGi063-B, NUIGi063-C) and 3 healthy controls (NUIGi064-A, NUIGi064-B, NUIGi064-C).

KCNQ2 encodes the potassium-gated voltage channel Kv7.2, responsible for the M-current, which contributes to neuronal resting membrane potential. Pathogenic variants in KCNQ2 cause early onset epilepsies, developmental and epileptic encephalopathies. In this study, we generated three iPSC lines from dermal fibroblasts of a 5 year-old female patient with the KCNQ2 c.638C > T (p.Arg213Gln) pathogenic heterozygous variant and three iPSC lines from a healthy sibling control. These iPSC lines were validated by confirming the targeted mutation, SNP karyotyping, STR analysis, pluripotent gene expression, differentiation capacity into three germ layers, and were free of transgene integration and Mycoplasma.

Generation of three induced pluripotent stem cell lines from a patient with KCNQ2 developmental and epileptic encephalopathy as a result of the pathogenic variant c.881C > T; p.Ala294Val (NUIGi059-A, NUIGi059-B, NUIGi059-C) and 3 healthy controls (NUIGi060-A, NUIGi060-B, NUIGi060-C).

Developmental and epileptic encephalopathies (DEEs) are a group of severe, early-onset epilepsies which are often caused by genetic mutations in ion channels. Mutations in KCNQ2, which encodes the voltage-gated potassium channel Kv7.2, is known to cause DEE. Here, we generated three iPSC lines from dermal fibroblasts of a 5 year-old male patient with the KCNQ2 c.881C > T (p.Ala294Val) pathogenic heterozygous variant and three iPSC lines from a healthy sibling control. These iPSC lines have been validated by SNP karyotyping, STR analysis, expression of pluripotent genes, the capacity to differentiate into three germ layers and confirmation of the mutation in the patient.

Using Ribonucleoprotein-based CRISPR/Cas9 to Edit Single Nucleotide on Human Induced Pluripotent Stem Cells to Model Type 3 Long QT Syndrome (SCN5A±).

Human induced pluripotent stem cells (hiPSCs) have been widely used in cardiac disease modelling, drug discovery, and regenerative medicine as they can be differentiated into patient-specific cardiomyocytes. Long QT syndrome type 3 (LQT3) is one of the more malignant congenital long QT syndrome (LQTS) variants with an SCN5A gain-of-function effect on the gated sodium channel. Moreover, the predominant pathogenic variants in LQTS genes are single nucleotide substitutions (missense) and small insertion/deletions (INDEL). CRISPR/Cas9 genome editing has been utilised to create isogenic hiPSCs to control for an identical genetic background and to isolate the pathogenicity of a single nucleotide change. In this study, we described an optimized and rapid protocol to introduce a heterozygous LQT3-specific variant into healthy control hiPSCs using ribonucleoprotein (RNP) and single-stranded oligonucleotide (ssODN). Based on this protocol, we successfully screened hiPSCs carrying a heterozygous LQT3 pathogenic variant (SCN5A±) with high efficiency (6 out of 69) and confirmed no off-target effect, normal karyotype, high alkaline phosphatase activity, unaffected pluripotency, and in vitro embryonic body formation capacity within 2 weeks. In addition, we also provide protocols to robustly differentiate hiPSCs into cardiomyocytes and evaluate the electrophysiological characteristics using Multi-electrode Array. This protocol is also applicable to introduce and/or correct other disease-specific variants into hiPSCs for future pharmacological screening and gene therapeutic development.