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.

What Is the Therapeutic Reference Range for Levetiracetam? Grand Round/A Case Study.

ABSTRACT: The Therapeutic Drug Monitoring guidelines of Arbeitsgemeinschaft für Neuropsychopharmakologie und Pharmakopsychiatrie had proposed a therapeutic reference range of 10-40 mg/L for levetiracetam in 2011. In the first version of the 2017 update, it was changed to 20-40 mg/L; however, 5 months later, in an erratum version, it was changed back to 10-40 mg/L. In this study, the authors agree with the range to 10-40 mg/L but discuss to what extent a wider interval may be proposed for certain patients.

Mutations in SLC13A5 cause autosomal-recessive epileptic encephalopathy with seizure onset in the first days of life.

Epileptic encephalopathy (EE) refers to a clinically and genetically heterogeneous group of severe disorders characterized by seizures, abnormal interictal electro-encephalogram, psychomotor delay, and/or cognitive deterioration. We ascertained two multiplex families (including one consanguineous family) consistent with an autosomal-recessive inheritance pattern of EE. All seven affected individuals developed subclinical seizures as early as the first day of life, severe epileptic disease, and profound developmental delay with no facial dysmorphism. Given the similarity in clinical presentation in the two families, we hypothesized that the observed phenotype was due to mutations in the same gene, and we performed exome sequencing in three affected individuals. Analysis of rare variants in genes consistent with an autosomal-recessive mode of inheritance led to identification of mutations in SLC13A5, which encodes the cytoplasmic sodium-dependent citrate carrier, notably expressed in neurons. Disease association was confirmed by cosegregation analysis in additional family members. Screening of 68 additional unrelated individuals with early-onset epileptic encephalopathy for SLC13A5 mutations led to identification of one additional subject with compound heterozygous mutations of SLC13A5 and a similar clinical presentation as the index subjects. Mutations affected key residues for sodium binding, which is critical for citrate transport. These findings underline the value of careful clinical characterization for genetic investigations in highly heterogeneous conditions such as EE and further highlight the role of citrate metabolism in epilepsy.

Epileptic patients with de novo STXBP1 mutations: Key clinical features based on 24 cases.

OBJECTIVE: Mutations in the syntaxin binding protein 1 gene (STXBP1) have been associated mostly with early onset epileptic encephalopathies (EOEEs) and Ohtahara syndrome, with a mutation detection rate of approximately 10%, depending on the criteria of selection of patients. The aim of this study was to retrospectively describe clinical and electroencephalography (EEG) features associated with STXBP1-related epilepsies to orient molecular screening. METHODS: We screened STXBP1 in a cohort of 284 patients with epilepsy associated with a developmental delay/intellectual disability and brain magnetic resonance imaging (MRI) without any obvious structural abnormality. We reported on patients with a mutation and a microdeletion involving STXBP1 found using array comparative genomic hybridization (CGH). RESULTS: We found a mutation of STXBP1 in 22 patients and included 2 additional patients with a deletion including STXBP1. In 22 of them, epilepsy onset was before 3 months of age. EEG at onset was abnormal in all patients, suppression-burst and multifocal abnormalities being the most common patterns. The rate of patients carrying a mutation ranged from 25% in Ohtahara syndrome to <5% in patients with an epilepsy beginning after 3 months of age. Epilepsy improved over time for most patients, with an evolution to West syndrome in half. Patients had moderate to severe developmental delay with normal head growth. Cerebellar syndrome with ataxic gait and/or tremor was present in 60%. SIGNIFICANCE: Our data confirm that STXBP1 mutations are associated with neonatal-infantile epileptic encephalopathies. The initial key features highlighted in the cohort of early epileptic patients are motor seizures either focal or generalized, abnormal initial interictal EEG, and normal head growth. In addition, we constantly found an ongoing moderate to severe developmental delay with normal head growth. Patients often had ongoing ataxic gait with trembling gestures. Altogether these features should help the clinician to consider STXBP1 molecular screening.

Angelman syndrome: a case series assessing neurological issues in adulthood.

BACKGROUND: This study aimed to evaluate the clinical symptoms of Angelman syndrome (AS) in adults and to identify the neurological pathways affected in this disease. AS is a neurogenetic disorder resulting due to the deletion or inactivation of the ubiquitin-protein-ligase E3A gene on maternal chromosome 15. SUMMARY: A retrospective analysis of data from six adults patients with clinical, electroencephalographic and genetic confirmation of AS was performed. Movement disorders of the hands and mouth, laughing spells, severe expressive speech disorders, a happy nature, hyposomnia and anxiety are the major neurological characteristics of AS in adulthood. Cerebellar ataxia, muscle hypotonia and tremor, though constant in childhood, tend to be attenuated in adulthood. Epilepsy, one of the most frequent symptoms in childhood and in adulthood, is characterised by specific electroencephalographic patterns. Key Messages: These clinical characteristics are important to improve the clinical awareness and genetic diagnosis of AS. Clinicians must be better informed concerning the adult phenotype as it is not well described in the literature. We stress the importance of AS as one of the main causes of intractable epilepsy. The authors suggest frontal and cerebellar dysfunction. Further functional cerebral imaging studies are necessary.

Effect of nusinersen after 3 years of treatment in 57 young children with SMA in terms of SMN2 copy number or type.

BACKGROUND: Spinal muscular atrophy (SMA) is a rare genetic neuromuscular disorder due to an autosomal recessive mutation in the survival motor neuron 1 gene (SMN1), causing degeneration of the anterior horn cells of the spinal cord and resulting in muscle atrophy. This study aimed to report on the 36-month follow-up of children with SMA treated with nusinersen before the age of 3 years. Changes in motor function, nutritional and ventilatory support, and orthopedic outcomes were evaluated at baseline and 36 months after intrathecal administration of nusinersen and correlated with SMA type and SMN2 copy number. RESULTS: We found that 93% of the patients gained new motor skills during the 3 years-standing without help for 12 of 37 and walking with help for 11 of 37 patients harboring three SMN2 copies. No patients with two copies of SMN2 can stand alone or walk. Patients bearing three copies of SMN2 are more likely to be spared from respiratory, nutritional, and orthopedic complications than patients with two SMN2 copies. CONCLUSION: Children with SMA treated with nusinersen continue to make motor acquisitions at 3 years after initiation of treatment. Children with two SMN2 copies had worse motor, respiratory, and orthopedic outcomes after 3 years of treatment than children with three copies.

Real-world multidisciplinary outcomes of onasemnogene abeparvovec monotherapy in patients with spinal muscular atrophy type 1: experience of the French cohort in the first three years of treatment.

BACKGROUND: Spinal muscular atrophy type 1 (SMA1) is the most severe and early form of SMA, a genetic disease with motor neuron degeneration. Onasemnogene abeparvovec gene transfer therapy (GT) has changed the natural history of SMA1, but real-world data are scarce. METHODS: A French national expert committee identified 95 newly diagnosed treatment-naive SMA1 patients between June 2019 and June 2022. We prospectively report on children treated with GT as the first and only therapy who had more than one-year of follow-up. RESULTS: Forty-six SMA1 patients received GT. Twelve patients received other treatments. Patients with respiratory insufficiency were oriented toward palliative care after discussion with families. Twenty-nine of the treated patients with more than 12 months of follow-up were included in the follow-up analysis. Among them, 17 had 24 months of follow-up. The mean age at treatment was 7.5 (2.1-12.5) months. Twenty-two patients had two SMN2 copies, and seven had three copies. One infant died in the month following GT due to severe thrombotic microangiopathy, and another died due to respiratory distress. Among the 17 patients with 24 months of follow-up, 90% required spinal bracing (15/17), three patients required nocturnal noninvasive ventilation, and two needed gastrostomy. Concerning motor milestones at the 24-month follow-up, all patients held their head, 15/17 sat for 30 s unassisted, and 12/17 stood with aid. Motor scores (CHOPINTEND and HINE-2) and thoracic circumference significantly improved in all patients. CONCLUSIONS: Our study shows favorable motor outcomes and preserved respiratory and feeding functions in treatment-naive SMA1 infants treated by GT as the first and only therapy before respiratory and bulbar dysfunctions occurred. Nevertheless, almost all patients developed spinal deformities.

Delineation of a new chromosome 20q11.2 duplication syndrome including the ASXL1 gene.

We report on three males with de novo overlapping 7.5, 9.8, and 10 Mb duplication of chromosome 20q11.2. Together with another patient previously published in the literature with overlapping 20q11 microduplication, we show that such patients display common clinical features including metopic ridging/trigonocephaly, developmental delay, epicanthal folds, and short hands. The duplication comprised the ASXL1 gene, in which de novo heterozygous nonsense or truncating mutations have recently been reported in patients with Borhing-Opitz syndrome. Because of craniofacial features in common with Borhing-Opitz syndrome, in particular metopic ridging/trigonocephaly, we suggest that duplication of ASXL1 contributes to the phenotype. These observations suggest a novel microduplication syndrome, and reporting of additional patients with molecular characterization will allow more detailed genotype-phenotype correlations.

Epileptic and nonepileptic features in patients with early onset epileptic encephalopathy and STXBP1 mutations.

PURPOSE: STXBP1 (MUNC18-1) mutations have been associated with various types of epilepsies, mostly beginning early in life. To refine the phenotype associated with STXBP1 aberrations in early onset epileptic syndromes, we studied this gene in a cohort of patients with early onset epileptic encephalopathy. METHODS: STXBP1 was screened in a multicenter cohort of 52 patients with early onset epilepsy (first seizure observed before the age of 3 months), no cortical malformation on brain magnetic resonance imaging (MRI), and negative metabolic screening. Three groups of patients could be distinguished in this cohort: (1) Ohtahara syndromes (n = 38); (2) early myoclonic encephalopathies (n = 7); and (3) early onset epileptic encephalopathies that did not match any familiar syndrome (n = 7). None of the patients displayed any cortical malformation on brain MRI and all were screened through multiple video-electroencephalography (EEG) recordings for a time period spanning from birth to their sixth postnatal month. Subsequently, patients had standard EEG or video-EEG recordings. KEY FINDINGS: We found five novel STXBP1 mutations in patients for whom video-EEG recordings could be sampled from the beginning of the disease. All patients with a mutation displayed Ohtahara syndrome, since most early seizures could be classified as epileptic spasms and since the silent EEG periods were on average shorter than bursts. However, each patient in addition displayed a particular clinical and EEG feature: In two patients, early seizures were clonic, with very early EEG studies exhibiting relatively low amplitude bursts of activity before progressing into a typical suppression-burst pattern, whereas the three other patients displayed epileptic spasms associated with typical suppression-burst patterns starting from the early recordings. Epilepsy dramatically improved after 6 months and finally disappeared before the end of the first year of life for four patients; the remaining one patient had few seizures until 18 months of age. In parallel, EEG paroxysmal abnormalities disappeared in three patients and decreased in two, giving place to continuous activity with fast rhythms. Each patient displayed frequent nonepileptic movement disorders that could easily be mistaken for epileptic seizures. These movements could be observed as early as the neonatal period and, unlike seizures, persisted during all the follow-up period. SIGNIFICANCE: We confirm that STXBP1 is a major gene to screen in cases of Ohtahara syndrome, since it is mutated in >10% of the Ohtahara patients within our cohort. This gene should particularly be tested in the case of a surprising evolution of the patient condition if epileptic seizures and EEG paroxysmal activity disappear and are replaced by fast rhythms after the end of the first postnatal year.

West Syndrome Is an Exceptional Presentation of Pyridoxine- and Pyridoxal Phosphate-Dependent Epilepsy: Data From a French Cohort and Review of the Literature.

Objective: To characterize the electro-clinical presentation of patients with pyridoxine-dependent epilepsy (PDE) and pyridoxal phosphate (PLP)-dependent epilepsy in order to determine whether some of them could be diagnosed as de novo West syndrome, i. e., West syndrome that starts after the age of 2 months without other types of seizures (focal seizures for instance) before the onset of epileptic spasms. Methods: We analyzed data from an unpublished cohort of 28 genetically confirmed cases of PDE with antiquitine (ATQ) deficiency and performed a review of the literature looking for description of West syndrome in patients with either PDE with ATQ deficiency or PLP-dependent epilepsy with Pyridox(am)ine phosphate oxidase (PNPO) deficiency. Results: Of the 28 cases from the ATQ deficiency French cohort, 5 had spasms. In four cases, spasms were associated with other types of seizures (myoclonus, focal seizures). In the last case, seizures started on the day of birth. None of these cases corresponded to de novo West syndrome. The review of the literature found only one case of PNPO deficiency presenting as de novo West syndrome and no case of ATQ deficiency. Significance: The presentation of PDE- and PLP-dependent epilepsy as de novo West syndrome is so exceptional that it probably does not justify a systematic trial of pyridoxine or PLP. We propose considering a therapeutic trial with these vitamins in West syndrome if spasms are associated with other seizure types or start before the age of 2 months.

The diagnostic rate of inherited metabolic disorders by exome sequencing in a cohort of 547 individuals with developmental disorders.

Considering that some Inherited Metabolic Disorders (IMDs) can be diagnosed in patients with no distinctive clinical features of IMDs, we aimed to evaluate the power of exome sequencing (ES) to diagnose IMDs within a cohort of 547 patients with unspecific developmental disorders (DD). IMDs were diagnosed in 12% of individuals with causative diagnosis (177/547). There are clear benefits of using ES in DD to diagnose IMD, particularly in cases where biochemical studies are unavailable. SYNOPSIS: Exome sequencing and diagnostic rate of Inherited Metabolic Disorders in individuals with developmental disorders.

Effects of nusinersen after one year of treatment in 123 children with SMA type 1 or 2: a French real-life observational study.

BACKGROUND: Spinal muscular atrophy (SMA) is an autosomal recessive neuromuscular disorder characterized by degeneration of the anterior horn cells of the spinal cord. Nusinersen has been covered by public healthcare in France since May 2017. The aim of this article is to report results after 1 year of treatment with intrathecal nusinersen in children with SMA types 1 and 2 in France. Comparisons between treatment onset (T0) and after 1 year of treatment (Y1) were made in terms of motor function and need for nutritional and ventilatory support. Motor development milestone achievements were evaluated using the modified Hammersmith Infant Neurologic Examination-Part 2 (HINE-2) for patients under 2 years of age and Motor Function Measure (MFM) scores for patients over 2 years of age. RESULTS: Data on 204 SMA patients (type 1 or 2) were retrospectively collected from the 23 French centers for neuromuscular diseases. One hundred and twenty three patients had been treated for at least 1 year and were included, 34 of whom were classified as type 1 (10 as type 1a/b and 24 as type 1c) and 89 as type 2. Survival motor Neuron 2 (SMN2) copy numbers were available for all but 6 patients. Patients under 2 years of age (n = 30), had significantly higher HINE-2 scores at year 1 than at treatment onset but used more nutritional and ventilatory support. The 68 patients over 2 years of age evaluated with the Motor Function Measure test had significantly higher overall scores after 1 year, indicating that their motor function had improved. The scores were higher in the axial and proximal motor function (D2) and distal motor function (D3) parts of the MFM scale, but there was no significant difference for standing and transfer scores (D1). No child in either of the two groups achieved walking. CONCLUSION: Nusinersen offers life-changing benefits for children with SMA, particularly those with more severe forms of the disorder. Caregiver assessments are positive. Nevertheless, patients remain severely disabled and still require intensive support care. This new treatment raises new ethical challenges.

Multiple cysts of the corpus callosum and psychomotor delay in a patient with a 3.1 Mb 15q24.1q24.2 interstitial deletion identified by array-CGH.

We describe a 46-month-old child presenting with developmental delay, mild facial dysmorphism, micropenis, strabismus and striking multiple cysts of the corpus callosum who was found to have a de novo interstitial 3.1 Mb 15q24.1q24.2 microdeletion using a 244 K microarray-based comparative genomic hybridization (array-CGH). The cystic lesions were located in the anterior half of the corpus callosum and did not take up gadolinium contrast. There was no other brain abnormality, and the gyral pattern and myelination were normal. There was no history of infectious disease or vascular injury and a metabolic disease was ruled out. Such cystic lesions of the corpus callosum are exceptional in the pediatric literature. Although these brain abnormalities have not been described in other reports with 15q24 microdeletion, we believe that they might be related to the cytogenetic abnormality since the work-up for other causes was negative. We suggest that a chromosomal rearrangement should be ruled out when such corpus callosum lesions are identified.

Nusinersen in patients older than 7 months with spinal muscular atrophy type 1: A cohort study.

OBJECTIVE: To evaluate the safety and clinical efficacy of nusinersen in patients older than 7 months with spinal muscular atrophy type 1 (SMA1). METHODS: Patients with SMA1 were treated with nusinersen by intrathecal injections as a part of the Expanded Access Program (EAP; NCT02865109). We evaluated patients before treatment initiation (M0) and at 2 months (M2) and 6 months (M6) after treatment initiation. Survival, respiratory, and nutritional data were collected. Motor function was assessed with the modified Hammersmith Infant Neurologic Examination Part 2 (HINE-2) and physiotherapist scales adjusted to patient age (Children's Hospital of Philadelphia Infant Test of Neuromuscular Disorders and the Motor Function Measure 20 or 32). RESULTS: We treated 33 children ranging in age from 8.3 to 113.1 months between December 2016 and May 2017. All patients were alive and were continuing treatment at M6. Median progress on the modified HINE-2 score was 1.5 points after 6 months of treatment (p < 0.001). The need for respiratory support significantly increased over time. There were no statistically significant differences between patients presenting with 2 and those presenting with 3 copies of the survival motor neuron 2 (SMN2) gene. CONCLUSIONS: Our results are in line with the phase 3 study for nusinersen in patients with SMA1 treated before 7 months of age and indicate that patients benefit from nusinersen even at a later stage of the disease. CLINICALTRIALSGOV IDENTIFIER: NCT02865109. CLASSIFICATION OF EVIDENCE: This study provides Class IV evidence that for patients with SMA1 who are older than 7 months, nusinersen is beneficial.

A new case of megalencephaly and perisylvian polymicrogyria with post-axial polydactyly and hydrocephalus: MPPH syndrome.

We report a new case of megalencephaly and polymicrogyria with post-axial polydactyly and hydrocephalus (MPPH syndrome) in an 18-month-old girl. She was the first child of healthy non-consanguineous parents and measurements at birth were +3 standard deviations (S.D.) for weight, +2 S.D. for length and +4 S.D. for OFC. Ultrasound scan at 24 weeks of gestation (WG) showed mild ventriculomagaly with unique umbilical artery and dacryocystocele. Clinical examination at birth revealed macrosomia with macrocephaly, facial dysmorphism, post-axial polydactyly at the right hand and both feet, and axial hypotonia with hypertonic arms and legs. At 18 months of age, weight was +2 S.D., length was +2 S.D. and OFC was +4 S.D. She remained hypertonic, could not sit and had no hand use. Cerebral magnetic resonance imaging showed stable ventriculomegaly and polymicrogyria located on the frontal and perisylvian region with white matter hypersignal on T2-weighted images. There was no associated visceral malformation. Standard and high-resolution cytogenetic examination, telomeric FISH and array-CGH studies were normal. This case represents the sixth observation of MPPH syndrome as described by Mirzaa et al. in 2004. We provide further neurological follow-up since three out of five index patients were aged 6 months or less. We postulate that macrosomia at birth might be a major feature (five/six cases), with advanced bone age in the two/two investigated cases. White matter abnormalities might be an occasional feature of this syndrome (three/six cases), as well as dacryocystocele, if not coincidental (one/six case). The mode of inheritance of this syndrome remains unknown since there was no significant family history in all reported cases. The search for infracytogenetic chromosomal imbalance was unsuccessful.

Gain-of-function mutations in IFIH1 cause a spectrum of human disease phenotypes associated with upregulated type I interferon signaling.

The type I interferon system is integral to human antiviral immunity. However, inappropriate stimulation or defective negative regulation of this system can lead to inflammatory disease. We sought to determine the molecular basis of genetically uncharacterized cases of the type I interferonopathy Aicardi-Goutières syndrome and of other undefined neurological and immunological phenotypes also demonstrating an upregulated type I interferon response. We found that heterozygous mutations in the cytosolic double-stranded RNA receptor gene IFIH1 (also called MDA5) cause a spectrum of neuroimmunological features consistently associated with an enhanced interferon state. Cellular and biochemical assays indicate that these mutations confer gain of function such that mutant IFIH1 binds RNA more avidly, leading to increased baseline and ligand-induced interferon signaling. Our results demonstrate that aberrant sensing of nucleic acids can cause immune upregulation.