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LGI1 gene
Reviewed by Medicinsk Expert•Last updated: 2026-10-22•Gene

LGI1 gene

The LGI1 gene encodes a protein involved in brain development and neuronal communication, with variants linked to a specific form of inherited epilepsy.

Normal Function

The LGI1 gene provides instructions for making a protein called leucine-rich glioma inactivated 1 (Lgi1) or epitempin. This protein is found primarily in nerve cells (neurons) in the brain, including the temporal lobe, which is involved in hearing, speech, memory, and emotion.

Although its precise role remains uncertain, the protein is likely involved in normal brain development. Research suggests the following functions:

  • Potassium channel regulation: Epitempin may play a role in the function of potassium channels, which are critical for electrical signaling in neurons.
  • Neuronal communication: Epitempin attaches to a receptor protein called ADAM22 on the surface of neurons. Together, these proteins help control the release of neurotransmitters, the chemicals that allow neurons to communicate.

Health Conditions Related to Genetic Changes

Autosomal dominant epilepsy with auditory features

Many variants in the LGI1 gene have been identified in people with autosomal dominant epilepsy with auditory features (ADEAF). People with this rare form of epilepsy typically hear sounds, like buzzing or humming, during seizures.

Variants associated with this condition may:

  • Alter the structure of the epitempin protein by changing a single amino acid.
  • Lead to the production of an abnormally short, nonfunctional version of the protein.

Researchers suspect that the altered protein is unable to be secreted, leaving it trapped inside cells. These changes may alter communication between neurons, leading to seizure activity.

Cancers

While researchers previously hypothesized that epitempin acted as a tumor suppressor in brain tumors called gliomas, more recent studies have called this into question. Because no LGI1 variants have been identified in gliomas and people with ADEAF do not show a significantly increased risk of these tumors, it is now considered unlikely that epitempin functions as a tumor suppressor.

Other Names for This Gene

  • EPITEMPIN
  • Epitempin 1
  • EPT
  • ETL1
  • IB1099
  • Leucine-Rich Glioma-Inactivated Protein 1
  • leucine-rich, glioma inactivated 1
  • LGI1_HUMAN

Frequently Asked Questions

Patients often report a sudden buzzing, humming, or ringing in the ears (aural hallucinations) that precede a seizure. Triggers can include sleep deprivation, stress, alcohol, or hormonal changes. A sudden onset of these auditory sensations, especially when followed by loss of consciousness or tonic‑clonic activity, should prompt immediate medical evaluation.
Yes. Some individuals with LGI1 variants report mild cognitive impairment, memory difficulties, or mood disorders such as anxiety or depression. There is also emerging evidence that certain LGI1 mutations may be linked to a higher incidence of temporal lobe epilepsy‑related cognitive decline, so regular neuropsychological assessment is advised.
Levetiracetam and lacosamide are frequently used because they target sodium and potassium channel modulation, which may counteract the abnormal potassium channel regulation seen in LGI1 mutations. Valproate and carbamazepine can also be effective, but response varies; a trial of levetiracetam is often first‑line. If seizures persist, a combination of levetiracetam with a sodium‑channel blocker may be considered.
neurologist will order a targeted next‑generation sequencing panel that includes LGI1, or a whole‑exome sequencing if the panel is negative. The test looks for single‑nucleotide variants, small insertions/deletions, or copy‑number changes in the LGI1 coding region. Confirmation may also involve Sanger sequencing of the specific variant in the patient and, if available, in family members.
Source: MedlinePlus, National Library of Medicine

MedlinePlus brings together authoritative health information from the National Library of Medicine (NLM), the National Institutes of Health (NIH), and other government agencies and health-related organizations.

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