Epilepsy-Linked Gene Is Discovered, Scientists Say

Stanford scientists announced Thursday that they have discovered a gene linked to a form of epilepsy, a finding that could spur research into new therapies for the puzzling brain disorder.

When inherited from both parents, the mutated gene causes a rare form of epilepsy, progressive myoclonus epilepsy. The gene is linked to a protein, cystatin B, that normally regulates certain enzymes within the cell.

That family of proteins had not previously been suspect in epilepsy, and scientists do not understand the link. Nor do they know whether this protein is involved only in this one particular form of epilepsy or whether it will lead to major insights into variants of the neurological disorder.

“We don’t know much about it. Now we have a hint, and it opens up a whole new pathway that we can start studying,” Stanford geneticist Richard Myers said Thursday.

“And by understanding the basic biology, that could lead to drug development,” he said. “The exciting thing about this is we have not just identified a rare form of epilepsy. It has broader implications.”

The research by Myers and colleagues at Stanford Medical School and the University of Helsinki in Finland, where this form of epilepsy is more common, appears in today’s edition of the journal Science.

Epilepsy, a disorder of the brain that causes seizures when nerve cells misfire signals, affects about 3% of the world’s population. Julius Caesar and Napoleon were both reputed to have had epilepsy.

In the United States, there are about 2 million people with the disorder and about 125,000 new cases diagnosed each year, although the form linked to the recent discovery is rare. It is also one of the more severe forms and tends to grow more severe over time, Myers said.

Identifying the gene may also lead to better diagnostic tools. That would be particularly useful for the progressive myoclonus patients, who can have a dangerous, even fatal, reaction to a common epilepsy drug, phenytoin (better known as Parke-Davis’ Dilantin), Myers said.

The Finnish researchers began seeking the gene about six years ago, using genealogical data and blood samples from about 30 Finnish families. That enabled them to track the gene’s location to a portion of chromosome 21.

The Stanford colleagues joined the search in 1991, drawing on data from the Human Genome Project with which Myers is affiliated, and new gene search techniques.