Congenital microcephaly causes smaller than average head circumference relative to age, sex and ethnicity and is most usually associated with a variety of neurodevelopmental disorders. The underlying etiology is highly heterogeneous and can be either environmental or genetic. Disruption of any one of multiple biological processes, such as those underlying neurogenesis, cell cycle and division, DNA repair or transcription regulation, can result in microcephaly. This etiological heterogeneity manifests in a clinical variability and presents a major diagnostic and therapeutic challenge, leaving an unacceptably large proportion of over half of microcephaly patients without molecular diagnosis. To elucidate the clinical and genetic landscapes of congenital microcephaly, we sequenced the exomes of 191 clinically diagnosed patients with microcephaly as one of the features. We established a molecular basis for microcephaly in 71 patients (37%), and detected novel variants in five high confidence candidate genes previously unassociated with this condition. We report a large number of patients with mutations in tubulin-related genes in our cohort as well as higher incidence of pathogenic mutations in MCPH genes. Our study expands the phenotypic and genetic landscape of microcephaly, facilitating differential clinical diagnoses for disorders associated with most commonly disrupted genes in our cohort.

Background: The accessibility of effective SMA (spinal muscular atrophy) treatment is resulting in a growing number of affected women reaching fertility age and deciding to conceive. Pregnancy in women with SMA is associated with a high risk of rapid progression of symptoms, including increased weakness, growing paresis, or even onset of respiratory failure requiring ventilation support. Muscle weakness frequently leads to disability, which in a high percentage is irreversible. Pre-term labor and delivery by cesarean section are the most commonly described cases in the literature. Methods: This paper aims to describe the first case in Europe, a 21-year-old patient treated with Nusinersen under the drug program during the third trimester of pregnancy. Despite the significant progression of the disease during pregnancy, the patient did not lose gait function. The pregnancy was ended at 33Hbd, and the baby’s condition was unremarkable. In addition to clinical data, this paper also discusses the economic aspects. Conclusions: Thanks to the rapid initiation of treatment, the patient did not lose her ability to walk, and a significant improvement in motor function was observed after the postpartum period. No side effects or negative effects on the fetus were observed.

Studies conducted on large populations show a lack of connection between vaccination and serious neurological symptoms. However, there are isolated cases that indicate such a relationship. These reports on adverse effects following immunization (AEFI) reduce social confidence in vaccination; however, their background may be rare genetic defects. The aim of the presented study was to examine if neurological AEFI in children may be associated with variants in genes related to neurodevelopment. To identify such possible associations, a descriptive study of the Polish case series was conducted. We performed next-generation sequencing in patients who, up to 4 weeks of injection of any vaccine, manifested neurological AEFI. We included 23 previously normally developing children with first seizures that occurred after vaccination. We identified pathogenic/likely pathogenic variants in genes engaged in neurodevelopment in nine patients and variants of uncertain significance in another nine patients. The mutated genes belonged to the group of genes related to epilepsy syndromes/epileptic encephalopathy. We showed that AEFI might have a genetic background. We hypothesized that in some AEFI patients, the vaccine might only trigger neurological symptoms that would have been manifested anyway as a result of a pathogenic variant in a gene engaged in neurodevelopment.

Mutations of the SCN1A gene, which encodes the voltage-dependent Na⁺ channel’s α subunit, are associated with diverse epileptic syndromes ranging in severity, even intra-family, from febrile seizures to epileptic encephalopathy. The underlying cause of this variability is unknown, suggesting the involvement of additional factors. The aim of our study was to describe the properties of mutated channels and investigate genetic causes for clinical syndromes’ variability in the family of five SCN1A gene p.Arg1596Cys mutation carriers. The analysis of additional genetic factors influencing SCN1A-associated phenotypes was conducted through exome sequencing (WES). To assess the impact of mutations, we used patch clamp analysis of mutated channels expressed in HEK cells and in vivo neural excitability studies (NESs). In cells expressing the mutant channel, sodium currents were reduced. NESs indicated increased excitability of peripheral motor neurons in mutation carriers. WES showed the absence of non-SCA1 pathogenic variants that could be causative of disease in the family. Variants of uncertain significance in three genes, as potential modifiers of the most severe phenotype, were identified. The p.Arg1596Cys substitution inhibits channel function, affecting steady-state inactivation kinetics. Its clinical manifestations involve not only epileptic symptoms but also increased excitability of peripheral motor fibers. The role of Nav1.1 in excitatory neurons cannot be ruled out as a significant factor of the clinical phenotype.

Background/Objectives: Epilepsy represents one of the most common chronic neurological disorders in children, with a considerable proportion of patients exhibiting resistance to pharmacotherapy despite the advent of novel antiseizure medications (ASMs) in recent decades. This retrospective study assesses the off-label administration of cenobamate—a newly approved antiseizure medication (ASM) for focal seizures in adults—in a cohort of paediatric patients with drug-resistant epilepsy at a single neurology centre. Methods: Clinical outcomes were reviewed retrospectively for 18 children who received cenobamate for at least 6 months. Results: Eighteen paediatric patients with drug-resistant epilepsy received cenobamate therapy at a neurology centre. The mean age was 164.6 months, and each patient had previously trialled an average of 8.7 antiseizure medications. During a follow-up period of up to 29 months, 39% of participants achieved complete seizure freedom, while five additional patients experienced a seizure reduction exceeding 80%. Concomitant clobazam use was common among the cohort. Adverse events were reported in 78% of patients, predominantly somnolence, though these were generally transient or manageable. One patient developed a temporary exacerbation of seizures, which resolved following a dosage adjustment. Many patients were able to reduce or discontinue other ASMs during the observation period. Conclusions: Cenobamate demonstrated acceptable tolerability in this paediatric cohort, and seizure improvements were observed in a subset of patients. Further clinical trials are warranted to comprehensively evaluate the efficacy and safety profile of cenobamate in this patient population.

Human parechoviruses, officially known as Parechovirus A (PeV-A), are more frequently reported as a significant cause of serious infections in newborns and young infants. We aimed to describe the clinical features and neurological outcomes of PeV-A encephalitis cases identified in Warsaw. Infants with suspected encephalitis were retrospectively identified in three hospitals in the summer of 2022. Cases of confirmed PeV-A infection had their comprehensive demographic, clinical, laboratory, imaging, and outcome data reviewed. The psychomotor development of the children up to the age of 2 years was assessed by using the standardized tools. We identified 18 cases of confirmed encephalitis with a PeV-A infection. Their median age was 16 days. Fourteen cases were included in the analysis, while one patient dropped out after the first visit. Most were boys (9/14), and one patient was born preterm. Three patients had white matter alterations on brain MRI at discharge. No significant neurologic sequelae were observed after acute illness. At the 24-month follow-up, based on the Bayley Scales of Infant and Toddler Development (BSID-IV) and the Brunet–Lézine Scale, the children showed no neurodevelopmental sequelae. Brain MRIs were obtained in all of the participants up to 12 months of age and revealed no significant lesions. Neurodevelopmental complications are not frequent in children after PeV-A encephalitis at 24 months of age. Continued follow-up in larger cohorts is needed to explore the predictors of long-term morbidity.