Objective: γ‐Aminobutyric acid (GABA)_A‐receptor subunit variants have recently been associated with neurodevelopmental disorders and/or epilepsy. The phenotype linked with each gene is becoming better known. Because of the common molecular structure and physiological role of these phenotypes, it seemed interesting to describe a putative phenotype associated with GABA_A‐receptor–related disorders as a whole and seek possible genotype–phenotype correlations.Methods: We collected clinical, electrophysiological, therapeutic, and molecular data from patients with GABA_A‐receptor subunit variants (GABRA1, GABRB2, GABRB3, and GABRG2) through a national French collaboration using the EPIGENE network and compared these data to the one already described in the literature.Results: We gathered the reported patients in three epileptic phenotypes: 15 patients with fever‐related epilepsy (40%), 11 with early developmental epileptic encephalopathy (30%), 10 with generalized epilepsy spectrum (27%), and 1 patient without seizures (3%). We did not find a specific phenotype for any gene, but we showed that the location of variants on the transmembrane (TM) segment was associated with a more severe phenotype, irrespective of the GABA_A‐receptor subunit gene, whereas N‐terminal variants seemed to be related to milder phenotypes.Significance: GABA_A‐receptor subunit variants are associated with highly variable phenotypes despite their molecular and physiological proximity. None of the genes described here was associated with a specific phenotype. On the other hand, it appears that the location of the variant on the protein may be a marker of severity. Variant location may have important weight in the development of targeted therapeutics.

We aim to assess the efficacy and tolerance of cannabidiol as adjunctive therapy for Rett syndrome (RTT) patients with epilepsy. We conducted a longitudinal observational study through a monocentric cohort of 46 patients with RTT. Patients were recruited from March 2020 to October 2022 and were treated with Epidyolex® (cannabidiol, CBD, 100 mg/mL oral solution). In our cohort, 26 patients had associated epilepsy (26/46 [56%]), and 10/26 (38%) were treated with CBD, in combination with clobazam in 50% of cases. The median dose at their last follow‐up was 15 mg/kg/day. The median treatment duration was 13 months (range: 1–32 months). CBD reduced the incidence of seizures in seven out of 10 patients (70%) with one seizure‐free patient, two patients with a reduction of seizures of more than 75%, and four patients with a decrease of more than 50%. No aggravation of symptoms or adverse effects were observed. Only one patient experienced a transitory drooling and somnolence episode at the CBD initiation. Half of the patients showed a reduction in agitation and/or anxiety attacks, and an improvement in spasticity was reported in 4/10 (40%) of patients. CBD appears to have potential therapeutic value for the treatment of drug‐resistant epilepsy in Rett syndrome. CBD is well tolerated and, when used in combination with clobazam, may increase the effectiveness of clobazam alone.

There is a paucity of data directly comparing the outcome of surgical techniques available for the treatment of hypothalamic hamartomas (HHs). This study aims to evaluate the safety and efficacy of commonly used surgical approaches in the treatment of HH-related epilepsy. A systematic review and individual participant data (IPD) meta-analysis was conducted. The PubMed, Embase, and Scopus online databases were searched without any date restrictions for original studies with more than 1 participant reporting on patients with HH-related epilepsy who underwent surgical treatment. Random-effects modeling was used to calculate the pooled proportions of seizure freedom (Engel I) at the last follow-up. IPD were used to perform mixed-effects logistic regression to identify predictors of seizure freedom and major postoperative complications. Sixty-four studies were included, and IPD on 517 patients were obtained. The overall quality of evidence was low. After the index procedure, the pooled proportion of overall seizure freedom was 50.0% (95% CI 42.7%-57.4%), which increased to 64.5% (95% CI 57.2%-71.5%) after multiple treatments. Magnetic resonance-guided laser interstitial thermal therapy (MRgLITT) and radiofrequency thermocoagulation (RFTC) demonstrated the highest efficacy at the last follow-up, with seizure freedom rates of 74.5% (95% CI 66.8%-81.7%) and 78.5% (95% CI 71.6%-84.8%), respectively. Factors independently associated with a lower likelihood of seizure freedom included multiple seizure types (odds ratio [OR] 0.296, 95% CI 0.140-0.624, p = 0.001) and previous surgery (OR 0.418, 95% CI 0.198-0.884, p = 0.023). Stereotactic radiosurgery (SRS) was the safest approach, with a pooled proportion of major complications of 0.0% (95% CI 0.0%-1.4%). Only surgical technique emerged as an independent predictor of major complications, with SRS (OR 0.024, 95% CI 0.002-0.292, p = 0.004), RFTC (OR 0.133, 95% CI 0.026-0.692, p = 0.017), and MRgLITT (OR 0.234, 95% CI 0.056-0.968, p = 0.045) being associated with a lower likelihood of major complications. MRgLITT and RFTC offer superior efficacy and safety compared with open microsurgery and should be considered as first-line options. Despite its lower efficacy, SRS is associated with few reported long-term complications, making it a viable alternative for select cases, such as small HHs with good baseline functioning. Direct comparisons between techniques are limited by short follow-up durations in RFTC and MRgLITT cohorts. Further large-scale, multicenter studies directly comparing these modalities are warranted.