SCN8A-related epilepsy is associated with a spectrum of seizure and neurodevelopmental phenotypes; however, there is limited information regarding nonseizure outcomes. We performed a cross-sectional study investigating quality of life (QoL) and adaptive functioning in this population utilizing the Quality of Life Inventory–Disability (QI-Disability) survey and Vineland Adaptive Behavior Scales (VABS). Nineteen patients with SCN8A pathogenic variants were included. There was a significant difference in QI-Disability and VABS scores between clinical epilepsy phenotypes. Greater seizure frequency and number of antiseizure medications were both associated with lower VABS and QI-Disability total scores, but number of antiseizure medications was associated with more QoL domains than seizure frequency. QI-Disability scores were positively associated with adaptive functioning except for the QoL domain of Negative Emotions. This study is the first to characterize the spectrum of QoL and adaptive functioning in the SCN8A-related disorder population and investigate their relationships to each other and to seizure outcomes. Both the QI-Disability and VABS show promise as potential clinical outcome assessments in future SCN8A-related disorder cohorts.
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