More Epilepsy Genes Identified as International Hunt Continues

Several research teams have reported success in identifying more genes linked to epilepsy in people.

Posted: June 17, 2002

Research teams in the United States, Canada and Australia have reported success in identifying more genes linked to epilepsy in people. All three groups' findings appeared in recent issues of the journal Nature Genetics.

Researchers at New York's Columbia University Health Sciences Center have identified a gene implicated in a rare form of epilepsy, a finding that they believe could provide insights into the cause of all types of epilepsy.

Hallucinations of Sound

Led by Ruth Ottman, Ph.D., investigators identified the gene, called LGI1, by extensively studying five families in which some members had an uncommon type of epilepsy that produces hallucinations of sound, among other symptoms. During a seizure, people with this type of epilepsy often hear sounds that are not real.

"The gene seems to play a role in how nerve cells migrate during development and create faulty wiring," Ottman said.

During the study, Ottman and her colleagues looked at the pattern of inheritance of auditory epilepsy in the five families. They collected blood from 105 members of those families and studied the DNA from 85 of them. They knew from prior studies of one family that a gene associated with epilepsy with auditory symptoms was on chromosome 10.

But during this research, the scientists identified the gene by studying the DNA from the first family and four other families and found mutations in affected individuals. The researchers found having a mutated copy of the LGI1 gene does not guarantee getting epilepsy. The disorder will develop in 70 percent of individuals who have mutations in the gene, they said.

"Most people with epilepsy do not have family members who are also affected, but unusual families that have multiple affected people can help scientists find genes associated with the condition," Ottman said. "Discovery of these genes can tell us a lot about the basic processes that lead to seizures."

Ottman is a professor of epidemiology in the Mailman School of Public Health and deputy director of research at the Gertrude H. Sergievsky Center, both at Columbia University.

Gene Linked to Epilepsy

An Australian research team reports that it has discovered a gene linked to epilepsy and learning disabilities.

The research team, led by Josef Gecz, M.D. of the Women & Children's Hospital Department of Cytogenetics and Molecular Genetics in Adelaide, concludes that the gene affects the way the brain works by controlling how, where and when other genes function.

A mutation in the gene, they report, can produce a number of different conditions, including epilepsy, infantile spasms (West syndrome), dystonia (a disorder of muscle tone) and learning problems.

The genetic material for their studies came from nine families in Norway, Canada, Belgium, and Australia.

The gene is found on the x-chromosome and, according to the researchers, is one of about 100 genes on that chromosome that can affect IQ.

"The really novel aspect to this gene is its involvement in epilepsy as well as in intellectual disability," Gecz said.

Juvenile Myoclonic Epilepsy

In Canada, P. Cossette, M.D. and colleagues at McGill University Health Center Research Institute in Montreal, have been hunting for a gene associated with juvenile myoclonic epilepsy, and now report they have found one.

Juvenile myoclonic epilepsy is a type of epilepsy that typically begins in the teen years.

The team screened 14 members of a French-Canadian family and found identical mutations of the GABRA1 gene in each of the eight family members who have juvenile myoclonic epilepsy.

The six family members who did not have the condition also did not have the gene mutation.

Editor's note: to help support research such as this, go to the Foundation's Gene Discovery Project.