The Schizophrenia Variant V1282F in SCN2A Causes Functional Impairment of NaV1.2

Abstract

Neuropsychiatric disorders such as schizophrenia are challenging to treat due to the biological complexity of the disease and the lack of knowledge of the underlying pathophysiology. Whole exome and genome sequencing studies have identified disease-linked rare variants in patients with large effect size. Here, we functionally characterize the schizophrenia linked variant V1282F in SCN2A, encoding the sodium channel Nav1.2. This variant was introduced into isogenic lines of hiPSCs using CRISPR/CAS9 genome editing tools. hiPSCs were then differentiated into cortical neurons to understand how the variant and gene may be contributing to disease. We observed a significant (~25%) decrease in sodium current in the V1282F neurons compared to control neurons, suggesting the mutation is causing a loss-of-channel function. These results were supported by recordings in recombinant cells overexpressing either the mutant or wildtype Nav1.2, with the mutant channel having significantly (~75%) lower current amplitude than wildtype. We hypothesize that this phenotype may contribute to disease either through the direct loss of neuronal activity or through subsequent abnormal neurodevelopment.