The leucine-rich (LRR) repeat is a 20-30 amino acid motif that forms a hydrophobic Alpha/Beta horseshoe fold, allowing it to accommodate several leucine residues within a tightly packed core. All LRR repeats contain a variable segment and a highly conserved segment, the latter of which accounts for 11 or 12 residues of the entire LRR motif. LGI2 (leucine-rich repeat LGI family, member 2), also known as KIAA1916 or LGIL2, is a 545 amino acid secreted protein that contains four LRR repeats and seven EAR repeats. Expressed in heart, brain and placenta, LGI2 shares high sequence similarity with other LGI family members and is thought to play a role in the pathogenesis of epileptic disorders.