DSCAM is a cell adhesion molecule belonging to the immunoglobulin superfamily. It is predominantly expressed in brain and contains six Fibronectin type-III domains and ten Ig-like C2-type domains. In mice, DSCAM is responsible for regulating isoneuronal self-avoidance, the tendency for sister arbors to avoid crossing each other and to spread out proportionately over an area. Isoneuronal self-avoidance is important for proper terminal branching (arborization). In some cell types, DSCAM also mediates heteroneuronal self-avoidance, which is important for the regular spacing of cell bodies and the prevention of hyperfasciculation. In humans, two DSCAM isoforms exist due to alternative splicing. The long isoform (also known as CHD2-42) is a single pass type I membrane protein, while the short isoform (CHD2-52), which lacks the C-terminal transmembrane containing region (amino acids 1572-2012), is secreted.