LGI1

Many variants (also called mutations) 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. Some of the variants associated with this condition change a single protein building block (amino acid) in the epitempin protein, which alters the protein's structure. Other variants lead to the production of an abnormally short, nonfunctional version of the protein. Researchers suspect that the altered protein is unable to be secreted, which would leave it trapped inside cells and unable to perform its usual functions. Changes to epitempin may alter communication between neurons, which can lead to seizure activity in the brain.

When the LGI1 gene was first described, researchers believed that it might play a role in the growth and progression of brain tumors called gliomas. Epitempin was thought to act as a tumor suppressor, which is a protein that keeps cells from growing and dividing too fast or in an uncontrolled way. More recent studies, however, have called into question the role of epitempin in cancerous tumors. Because no LGI1 variants have been identified in gliomas and people with ADEAF do not appear to have a significantly increased risk of these tumors, it now appears unlikely that epitempin functions as a tumor suppressor.