STXBP1 Encephalopathy With Epilepsy

STXBP1-related disorders (STXBP1-RD) are rare genetic neurodevelopmental disorders, caused by pathogenic variants in the gene STXBP1. The core clinical features of the disorder are developmental delay often leading to (severe) intellectual disability and seizures in most patients, although the phenotypic spectrum is variable. Behavioral problems and movement disorders are frequent comorbidities. STXBP1-RD are severe disorders with significant impact on the quality of life of the patients and their caregivers. At the moment, there is no cure for STXBP1-RD and treatment is largely limited to symptom control. Recent advances in the field of precision medicine and gene therapy have led to the identification of potential novel disease modifying therapies for STXBP1-RD that hold promise to reach clinical trials in the coming years. However, accurate and successful evaluation of such novel precision therapies in STXBP1-RD patients is challenging, given the rarity of the condition and the variable clinical spectrum. Furthermore, relevant clinical endpoints, taking into account the patients' and caregivers' perspective have not been identified to date. In this European collaborative study, the investigators will prospectively follow patients with STXBP1-RD during different phases of life (infantile period, childhood and adolescence/adulthood). The study aims to better understand the natural history and the phenotypic spectrum of the disease including the identification of disease modifiers. It further aims to identify relevant clinical endpoints (what to treat?) and robust outcome measures and biomarkers (how to measure?) for future clinical trials. The study is performed in close collaboration with different STXBP1 patient-caregiver communities across Europe.

The purpose of this study is to find out more about STXBP1 and SYNGAP1 related disorders. The information gathered by this study will be used to prepare for clinical treatment trials. The primary objective of the study is to better define and outline the clinical spectrum of STXBP1 and SYNGAP1 through detailed developmental, seizure, and quality of life assessments as an extension of routine clinical care.

Simons Searchlight is an observational, online, international research program for families with rare genetic variants that cause neurodevelopmental disorders and may be associated with autism. Simons Searchlight collects medical, behavioral, learning, and developmental information from people who have these rare genetic changes. The goal of this study is to improve the clinical care and treatment for these people. Simons Searchlight partners with families to collect data and distribute it to qualified researchers.

This is a prospective observational study to evaluate the phenotype of 10 patients under 10 years of age with developmental epileptic encephalopathy due to mutation of the STXBP1 gene. The study will consist of a clinical and neurodevelopmental evaluation, magnetic resonance imaging, prolonged electroencephalogram, cardiological study, and analysis of biomarkers in cerebrospinal fluid. These patients will be followed up for 3 years. The aim of the study is, knowing the baseline phenotype, to analyse the response to commonly used drugs and to anticipate the response to different drugs available on the market in this group of patients based on clinical and biomarker assessment (EEG, MRI and study of specific proteins and neurotransmitters in plasma, urine and CSF).