Search

Genetic variants in the SLC6A1 gene can cause a broad phenotypic disease spectrum by altering the protein function. Thus, systematically curated clinically relevant genotype-phenotype associations are needed to understand the disease mechanism and improve therapeutic decision-making. We aggregated genetic and clinical data from 172 individuals with likely pathogenic/pathogenic (lp/p) SLC6A1 variants and functional data for 184 variants (14.1% lp/p). Clinical and functional data were available for a subset of 126 individuals. We explored the potential associations of variant positions on the GAT1 3D structure with variant pathogenicity, altered molecular function and phenotype severity using bioinformatic approaches. The GAT1 transmembrane domains 1, 6 and extracellular loop 4 (EL4) were enriched for patient over population variants. Across functionally tested missense variants (n = 156), the spatial proximity from the ligand was associated with loss-of-function in the GAT1 transporter activity. For variants with complete loss of in vitro GABA uptake, we found a 4.6-fold enrichment in patients having severe disease versus non-severe disease (P = 2.9 × 10-3, 95% confidence interval: 1.5-15.3). In summary, we delineated associations between the 3D structure and variant pathogenicity, variant function and phenotype in SLC6A1-related disorders. This knowledge supports biology-informed variant interpretation and research on GAT1 function. All our data can be interactively explored in the SLC6A1 portal (https://slc6a1-portal.broadinstitute.org/)., (© The Author(s) 2023. Published by Oxford University Press on behalf of the Guarantors of Brain.)

Study Objectives: CDKL5 deficiency disorder (CDD) is a rare developmental and epileptic encephalopathy, developing in the first months of life, caused by a mutation in the cyclin-dependent kinase-like 5 (CDKL5) gene. Children with CDD often have sleep (90%) and breathing disorders in wake (50%). Sleep disorders may have a significant impact emotional wellbeing and quality of life of caregivers of children with CDD and are challenging to treat. The outcomes of these features are unknown in children with CDD., Methods: We retrospectively evaluated sleep and respiratory function changes over 5-10 years in a small cohort of Dutch children with CDD, using video-EEG and/or polysomnography (3 × 24 h) and a parental questionnaire, the Sleep Disturbance Scale for Children (SDSC). The present study is a follow-up sleep and PSG study to evaluate if sleep and breathing disturbances persist in children with CDD previously studied., Results: Sleep disturbances persisted during the study period (5.5-10 years). All five individuals had long sleep latency (SL, range 32-174.5 min) and frequent arousals and awakenings (14-50/night), unrelated to apneas/seizures, corresponding to the SDSC findings. Low sleep efficiency (SE, 41-80%) was present and did not improve. In our participants, total sleep time (TST, 3h52min-7h52min) was short and remained so. Time in bed (TIB) was typical for children aged 2-8 years, but did not adjust with ageing. Low duration (4.8-17.4%) or even absent REM sleep persisted over time. No sleep apneas were noted. Central apneas due to episodic hyperventilation were reported during wakefulness in two of the five., Conclusion: Sleep disturbances were present and persisted in all. The decreased REM sleep and sporadic breathing disturbances in wake may indicate failure of brainstem nuclei. Sleep disturbances can severely affect the emotional wellbeing and quality of life of the caregivers and the individuals with CDD and are challenging to treat. Hopefully our polysomnographic sleep data contribute to find the optimal treatment of the sleep problems in CDD patients., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. None., (Copyright © 2023. Published by Elsevier B.V.)

Introduction: Caring for a child with epilepsy has a significant impact on parental quality of life. Seizure unpredictability and complications, including sudden unexpected death in epilepsy (SUDEP), may cause high parental stress and increased anxiety. Nocturnal supervision with seizure detection devices may lower SUDEP risk and decrease parental burden of seizure monitoring, but little is known about their added value in family homes., Methods: We conducted semi-structured in-depth interviews with parents of children with refractory epilepsy participating in the PROMISE trial (NCT03909984) to explore the value of seizure detection in the daily care of their child. Children were aged 4-16 years, treated at a tertiary epilepsy center, had at least one nocturnal major motor seizure per week, and used a wearable seizure detection device (NightWatch) for two months at home. Data were analyzed using inductive thematic analysis., Results: Twenty three parents of nineteen children with refractory epilepsy were interviewed. All parents expressed their fear of missing a large seizure and the possible consequences of not intervening in time. Some parents felt the threat of child loss during every seizure, while others thought about it from time to time. The fear could fluctuate over time, mainly associated with fluctuations of seizure frequency. Most parents described how they developed a protective behavior, driven by this fear. The way parents handled the care of their child and experienced the burden of care influenced their perceptions on the added value of NightWatch. The experienced value of NightWatch depended on the amount of assurance it could offer to reduce their fear and the associated protective behavior as well as their resilience to handle the potential extra burden of care, due to false alarms or technical problems., Conclusion: Healthcare professionals and device companies should be aware of parental protective behavior and the high parental burden of care and develop tailored strategies to optimize seizure detection device care., (Copyright © 2021 The Authors. Published by Elsevier Inc. All rights reserved.)