Sodium channel protein type 2 subunit alpha, also known as Nav1.2, is an ion channel protein encoded by the SCN2A gene in humans. It represents one member of the sodium channel alpha subunit gene family. The SCN2A gene is located on chromosome 2 (2q24.3) in proximity to two other voltage-gated sodium channel genes, namely SCN1A and SCN9A. Nav1.2 is distributed throughout the human central nervous system where it plays a major role in the initiation and propagation of action potentials. It is absent from peripheral tissues, with the exception of enteric neurons. Pathologic mutations in the SCN2A gene cause a broad spectrum of neurological conditions, such as epilepsy, autism spectrum disorder (ASD), intellectual disability (ID) and/or developmental delay, called SCN2A-related disorders.