Natural History and Developmental Trajectories of Individuals With Disease-Causing Variants in STXBP1

Prevalence of bruxism in patients affected by epilepsy: a systematic review and meta-analysis

BACKGROUND

Bruxism, defined by the involuntary grinding or clenching of teeth, and epilepsy, a neurological ailment marked by recurring seizures, are both common conditions that can significantly affect persons' quality of life. Although numerous studies have investigated the relationship between bruxism and epilepsy, the current evidence is ambiguous. This systematic review seeks to consolidate existing information to elucidate the association between bruxism and epilepsy.

METHODS

In accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guideline, a systematic search was performed across electronic databases, including PubMed, Lilacs, and Web of Science. The search encompassed all pertinent publications published until September 2021. The inclusion criteria were established to encompass observational studies (cohort, case-control, cross-sectional) that investigated the relationship between bruxism and epilepsy in human populations.

RESULTS

The preliminary search produced a total of 142 articles. After a rigorous screening process, 3 studies were declared appropriate for inclusion in the systematic review. The research varied in design, sample size, and methodology, with some studying the prevalence of bruxism in epileptic patients, while others studied the prevalence of epilepsy in individuals with bruxism. Heterogeneity among the research was handled using proper statistical analyses.

CONCLUSION

The findings from the included studies suggested a probable link between bruxism and epilepsy. However, the evidence was uneven and equivocal, with some research indicating a favourable correlation, while others showed no meaningful relationship. Methodological restrictions, such as changes in diagnostic criteria and data collection procedures, could contribute to the observed inconsistencies. In addition, the possible influence of confounding factors, such as medication use and comorbidities, should be addressed in interpreting the data.

Adult phenotypes of genetic developmental and epileptic encephalopathies

Developmental and epileptic encephalopathies constitute a group of severe epilepsies, with seizure onset typically occurring in infancy or childhood, and diverse clinical manifestations, including neurodevelopmental deficits and multimorbidities. Many have genetic aetiologies, identified in up to 50% of individuals. Whilst classically considered paediatric disorders, most are compatible with survival into adulthood, but their adult phenotypes remain inadequately understood. This cross-sectional study presents detailed phenotypes of 129 adults (age range 17-71 years), with genetic developmental and epileptic encephalopathies involving causal variants in 42 genes. We describe diverse disease aspects, and we sought genetic insights from the age-related trends of expression of the genes involved. Most developmental and epileptic encephalopathies (69.7%) are epileptic encephalopathies in adulthood, with the presence of epileptic encephalopathy correlating with worse cognitive phenotypes (P = 0.0007). However, phenotypic variability was observed, ranging from those with epileptic encephalopathy to seizure-free individuals with normal EEG or intermediate clinical and EEG phenotypes. This variability was found across individual genes and age-related gene expression trends, suggesting that other influential factors are likely at play. Mobility, feeding and communication impairments were common, with significant dependence on others for activities of daily living. Neurological and psychiatric comorbidities were most prevalent, along with additional systemic comorbidities observed, particularly musculoskeletal, cardiac and gastrointestinal conditions, highlighting the need for comprehensive and multisystemic monitoring. Despite an average diagnostic delay of 25.2 years, aetiology-based therapeutic interventions were feasible for 54.8% of the cohort, underscoring the critical need for genome-wide genetic testing for adults with these phenotypes. Optimizing seizure control remains necessary, but it may not be sufficient to ensure good outcomes, which may differ significantly from childhood metrics, like cognitive function and independence in daily living. Therapies addressing additional aspects beyond seizures are necessary for improving overall outcomes. Understanding the intricate relationship between molecular pathways and the age-related trends of gene expression is crucial for development of appropriate gene-specific therapies and timely intervention. Whilst prospective data are also needed to define these complexities, such studies of necessity take years to acquire: insights from adults can inform care strategies for both paediatric and adult populations now.

Developmental and epileptic encephalopathy 56 due to YWHAG variants: 12 new cases and review of the literature

BACKGROUND AND OBJECTIVES

Developmental and epileptic encephalopathy 56 (DEE-56) is caused by pathogenic variants in YWHAG and is characterized by early-onset epilepsy and neurodevelopmental delay. This study reports on a cohort of DEE-56 individuals, correlating antiseizure medication usage and comorbidities, to aid in understanding disease evolution.

METHODS

We analyzed data from thirty-nine individuals aged 3-40 years with YWHAG variants, including 12 previously unreported individuals (2 of these with recurrent distal 7q11.23 deletions) and 27 previously published cases (21 families, including 3 adult individuals reported in a family case). Our assessments encompassed clinical, radiological, and genetic evaluations. All procedures adhered to standardized protocols for patient approvals, registrations, and data collection.

RESULTS

Individuals with YWHAG variants exhibited variable psychomotor delay, with the majority experiencing mild intellectual disability. Early-onset seizures, particularly febrile seizures, were common, with various seizure types reported. Valproic acid has emerged as an effective antiseizure medication. Movement disorders were present in a subset of individuals, primarily manifesting as ataxia and tremor. Comorbidities such as autism spectrum disorders and attention deficit-hyperreactivity disorder were observed in a proportion of individuals. We identified a novel YWHAG variant (c.634_645del/p.Asn212_Ser215del) and expanded the genotypic spectrum of the disease.

CONCLUSIONS

We provide insights into the clinical, radiological, and genetic features of YWHAG-related epileptic encephalopathy. Despite mild clinical symptoms, affected individuals face challenges in daily functioning, underscoring the need for comprehensive care. Valproic acid has been used for seizure control with variable results.

Genetic Diagnosis in Neonatal Encephalopathy With Hypoxic Brain Damage Using Targeted Gene Panel Sequencing

BACKGROUND AND PURPOSE

Neonatal encephalopathy (NE) is a neurological syndrome that presents with severe neurological impairments and complications. Hypoxic-ischemic encephalopathy is a major contributor to poor outcomes, being responsible for 50%-80% of admissions to neonatal intensive care units. However, some cases of NE accompanied by hypoxic brain damage cannot be solely attributed to hypoxia-ischemia. We aimed to identify diverse pathogenic genetic variations that may be associated with cases of NE accompanied by hypoxic brain damage rather than hypoxia-ischemia.

METHODS

We collected data from 34 patients diagnosed with NE accompanied by hypoxic brain damage over a 10-year period. Patients with the following specific conditions were excluded: 1) premature birth (<32 weeks), 2) no history of hypoxic events, 3) related anomalies, 4) neonatal infections, 5) antenatal or perinatal obstetrical complications, 6) severe hypoxia due to other medical conditions, and 7) early death (within 1 week). A comprehensive review of clinical and radiological features was conducted.

RESULTS

A genetic diagnosis was made in 11 (32.4%) patients, with pathogenic variants being identified in the following 9 genes: CACNA1A (n=2), KCNQ2 (n=2), SCN2A (n=1), SCN8A (n=1), STXBP1 (n=1), NSD1 (n=1), PURA (n=1), ZBTB20 (n=1), and ENG (n=1). No specific treatment outcomes or clinical features other than preterm birth were associated with the results of the genetic analyses. Personalized treatments based on the results of genetic tests were attempted, such as the administration of sodium-channel blockers in patients with KCNQ2 or SCN8A variants and the implementation of a ketogenic diet in patients with STXBP1 or SCN2A mutations, which demonstrated some degree of effectiveness in these patients.

CONCLUSIONS

Genetic analyses may help in diagnosing the underlying etiology of NE and concurrent hypoxic brain damage, irrespective of the initial clinical features.

STXBP1-Related Disorders: Clinical Presentation, Molecular Function, Treatment, and Future Directions

In recent years, the affordability and availability of genetic testing have led to its increased use in clinical care. The increased frequency of testing has led to STXBP1 variants being identified as one of the more common variants associated with neurological disorders. In this review, we aim to summarize the common clinical phenotypes associated with STXBP1 pathogenic variants, provide an overview of their known natural history, and discuss current research into the genotype to phenotype correlation. We will also provide an overview of the suspected normal function of the STXBP1-encoded Munc18-1 protein, animal models, and experimental techniques that have been developed to study its function and use this information to try to explain the diverse phenotypes associated with STXBP1-related disorders. Finally, we will explore current therapies for STXBP1 disorders, including an overview of treatment goals for STXBP1-related disorders, a discussion of the current evidence for therapies, and future directions of personalized medications for STXBP1-related disorders.