Objective: Cardiofaciocutaneous syndrome (CFCS) is a rare developmental disorder caused by upregulated signaling through the RAS-mitogen-activated protein kinase (MAPK) pathway, mostly resulting from de novo activating BRAF mutations. Children with CFCS are prone to epilepsy, which is a major life-threatening complication. The aim of our study was to define the natural history of epilepsy in this syndrome and exploring genotype–phenotype correlations. Methods: We performed an observational study, including 34 patients with molecularly confirmed diagnosis (11 males, mean age: 15.8 years). The mean follow-up period was 9.2 years. For all patients, we performed neurological examination, cognitive assessment when possible, neuroimaging, electrophysiological assessment and systematic assessment of epilepsy features. Correlation analyses were performed, taking into account gender, age of seizure onset, EEG features, degree of cognitive deficits, type of mutation, presence of non-epileptic paroxysmal events and neuroimaging features. Results: Epilepsy was documented in 64% of cases, a higher prevalence compared to previous reports. Patients were classified into three groups based on their electroclinical features, long-term outcome and response to therapy. A genotype–phenotype correlation linking the presence/severity of epilepsy to the nature of the structural/functional consequences of mutations was observed, providing a stratification based on genotype to improve the clinical management of these patients.

Objective: Highly purified cannabidiol (CBD) is approved as adjunctive therapy for seizures associated with Dravet syndrome (DS), Lennox–Gastaut syndrome (LGS), and tuberous sclerosis complex (TSC), although its role in other developmental and epileptic encephalopathies (DEEs) remains unexplored. The aim of this study was to assess the real‐world use, efficacy, and safety of CBD across a broad cohort of patients with DEEs, including off‐label indications. Methods: In this retrospective study, we evaluated 107 patients with DEEs treated with CBD for ≥3 months between 2020 and 2024. Data on seizure frequency, tolerability, retention, and non‐seizure outcomes were collected. Efficacy was defined as ≥50% or ≥75% seizure reduction. Statistical analyses explored predictors of response. Results: Patients had LGS (55.1%), DS (16.8%), TSC (8.4%), or other DEEs (19.6%), with a genetic etiology in 56.1%. At a median follow‐up of 20 months, 69% achieved ≥50% seizure reduction, and 21% achieved ≥75% reduction. Patients with LGS, TSC, and other DEEs showed higher efficacy and retention rates compared to DS. Genetic or unknown etiology was associated with better outcomes ( p = 0.011). Combination with valproate was associated with reduced efficacy ( p = 0.006), while combination with clobazam had no significant effect on efficacy nor safety. Non‐seizure improvements included increased alertness (56%), improved sleep quality (25%), and enhanced motor performance (14%). Adverse events occurred in 33.6%, mostly mild and transient; 9% discontinued due to side effects. Significances: This study confirms the effectiveness and good tolerability of CBD in a real‐world DEE population, including off‐label use. These findings support expanding CBD indications and underscore the need for prospective studies targeting both seizure and developmental outcomes. Plain language summary: This study looked at the use of cannabidiol (CBD), a cannabis‐based medicine, in 107 people with severe forms of epilepsy called developmental and epileptic encephalopathies (DEEs). With CBD add‐on, about two‐thirds of patients had fewer seizures, and some caregivers noticed improvements in alertness, sleep, or movement. Most patients tolerated the treatment well, but some experienced side effects, and a few had to stop taking it. While the results are promising, more research is needed to confirm how effective and safe CBD is for different types of DEEs, especially those not currently approved for treatment with CBD.

Background: GNAO1-related encephalopathies include a broad spectrum of developmental disorders caused by de novo heterozygous mutations in the GNAO1 gene, encoding the G (o) subunit α of G-proteins. These conditions are characterized by epilepsy, movement disorders and developmental impairment, in combination or as isolated features. Objective: This study aimed at describing the profile of neurovisual competences in children with GNAO1 deficiency to better characterize the phenotype of the disease spectrum. Methods: Four male and three female patients with confirmed genetic diagnosis underwent neurological examination, visual function assessment, and neurovisual and ophthalmological evaluation. Present clinical history of epilepsy and movement disorders, and neuroimaging findings were also evaluated. Results: The assessment revealed two trends in visual development. Some aspects of visual function, such as discrimination and perception of distance, depth and volume, appeared to be impaired at all ages, with no sign of improvement. Other aspects, reliant on temporal lobe competences (ventral stream) and more related to object–face exploration, recognition and environmental control, appeared to be preserved and improved with age. Significance: Visual function is often impaired, with patterns of visual impairment affecting the ventral stream less.

Objective: Lennox–Gastaut syndrome (LGS) is a developmental and epileptic encephalopathy defined by polymorphic seizures, intellectual disability (ID), and characteristic electroencephalographic (EEG) patterns. The applicability and biological validity of current electroclinical criteria remain debated. This study evaluated the concordance between clinical and electroclinical definitions of LGS and applied unsupervised clustering to identify data‐driven profiles within LGS. Methods: We retrospectively analyzed patients clinically fulfilling LGS criteria, with longitudinal electroclinical documentation and at least one sleep EEG. Patients meeting complete electroclinical criteria were compared with those meeting clinical criteria alone. Additionally, exploratory unsupervised K‐modes clustering and discriminant correspondence analysis were applied in adolescent and adult patients. Results: We included 105 patients (60.9% female), with a median age of 24 years (interquartile range = 16–35). Sixty‐nine patients (65.7%) met complete electroclinical criteria, yet neurodevelopmental features, seizure types, magnetic resonance imaging (MRI) findings, and treatment refractoriness were comparable to the clinically defined subgroup. K‐modes clustering ( n = 97 patients) identified three data‐driven electroclinical profiles. Cluster 1 comprised patients with the earliest seizure onset, profound intellectual and motor impairment, EEG background slowing, lower prevalence of generalized paroxysmal fast activity (GPFA), highest prevalence of structural etiologies, and lowest likelihood of meeting complete electroclinical criteria for LGS. Among clusters more frequently fulfilling complete electroclinical criteria, Cluster 2 represented an early onset profile with higher rates of ID, EEG background slowing, and high prevalence of polymorphic seizures. Cluster 3 included comparatively preserved patients, characterized by later onset, milder neurodevelopmental impairment, and higher frequency of normal MRI. Despite similar clinical severity, Cluster 1 patients had undergone fewer antiseizure medication trials. Significance: Exploratory data‐driven clustering identified clinically relevant electroclinical profiles that may help refine phenotypic stratification within clinically defined LGS. These included a severe GPFA‐underrepresented profile and two GPFA‐positive phenotypes differing in developmental severity, seizure profile, and age at onset.

Objective: CDKL5 deficiency disorder (CDD) is an early‐onset developmental and epileptic encephalopathy characterized by frequent drug‐resistant seizures, cerebral visual impairment, motor dysfunction, and sleep and gastrointestinal disturbances. Preliminary evidence suggests that highly purified cannabidiol (CBD) may reduce seizure frequency, but data on its effects on comorbidities are lacking. This study aimed to evaluate the efficacy and safety of CBD in individuals with CDD. Methods: We conducted a prospective, open‐label, single‐center study including patients with CDD aged >1 year. Outcomes included motor seizure frequency, caregiver‐ and clinician‐rated Clinical Global Impression (CGI), and changes in sleep, motor abilities, and EEG at 3, 6, and 12 months. CBD plasma levels were measured with High‐Performance Liquid chromatography–Mass Spectrometry (HPLC‐MS). Results: Eight of nine patients (all females; median age 10 years, range 1–24) completed the study, with a retention rate at 12 months of 8/9 (89%). One discontinued at 6 months due to a skin rash. A > 50% seizure reduction was observed in 8/9 patients at 3 months, 6/9 at 6 months, and 1/8 at 12 months. Seven patients showed some degree of vigilance improvements, three in motor performance, and two in sleep and constipation. All caregivers reported at least minimal overall improvement (CGI score 3) at 3 months, and three reported marked improvement (CGI score 2), with a peak at 3 months. Five patients showed adverse events during the trial, but none were considered serious. The median CBD dose at all time‐points was 15.6 mg/kg/day (IQR 10.0–18.9) corresponding to a plasma dose of 69.9 ng/mL (IQR 29.8–114.6) and the median concentration/dose ratio was 4.7 (IQR 2.7–6.8). Significance: The safety and efficacy of highly purified CBD in CDD were consistent with previous reports in the literature, with possible benefits beyond seizure control. Further studies are warranted to assess non‐seizure outcomes and compare long‐term efficacy across treatment options. Plain Language Summary: We studied nine girls with CDKL5 deficiency disorder who had frequent, hard‐to‐treat seizures. They received cannabidiol for up to 1 year, added to their usual medicines. Most children had fewer seizures in the first months of treatment. Some families also noticed better alertness, eye contact, movement, sleep, or constipation. Side effects were usually mild and manageable. Although seizure frequency often returned to baseline by the end of the study, most families chose to continue cannabidiol. Because this was a small study without a placebo group, these results are preliminary, and larger controlled trials are needed.