The leucine-rich, glioma inactivated gene 1 (LGI1) was first identified as a candidate tumor suppressor gene for glioma and may play a role in other cancers. LGI1 is a member of a family of highly related proteins containing leucine-rich repeats (LRRs) which are highly similar to other transmembrane signaling molecules and receptors. LGI1 serves as a ligand to ADAM22, a metalloprotease localized at the synapse. Mutations in LGI1 account for nearly half of autodominant lateral temporal epilepsy (ADTLE), an epileptic syndrome characterized by focal seizures with predominant auditory symptoms. Two isoforms of LGI1 are known to exist; this LGI1 antibody will recognize only the longer form.