Leucine-rich, glioma inactivated 1, also known as LGI1, is a protein which in humans is encoded by the LGI1 gene. It may be a metastasis suppressor. The leucine-rich glioma inactivated -1 gene is rearranged as a result of translocations in glioblastoma cell lines. The protein contains a hydrophobic segment representing a putative transmembrane domain with the amino terminus located outside the cell. It also contains leucine-rich repeats with conserved cysteine-rich flanking sequences. This gene is predominantly expressed in neural tissues and its expression is reduced in low grade brain tumors and significantly reduced or absent in malignant gliomas. Since its earliest discovery, the LGI1 gene has been implicated in the control of cancer metastasis and in a predisposition to epilepsy. Following genetic linkage studies placing the hereditary form of autosomal dominant partial epilepsy with auditory features (ADPEAF) on chromosome region 10q24 mutation analysis of affected members in these families demonstrated LGI1 was a major cause of the disease.