BAR HARBOR, Maine -- Researchers at The Jackson Laboratory and colleagues have identified the gene for the epilepsy mutation in mice known as "stargazer" and report that the novel gene, Cacng2, produces a defect in a neuronal calcium channel that may play a key role in absence, or petit mal, epilepsy.
The research paper, "The mouse stargazer encodes a neuronal Ca2+-channel gamma subunit," is published in the August issue of the scientific journal Nature Genetics by a team led by Drs. Verity A. Letts and Wayne N. Frankel of The Jackson Laboratory, in collaboration with Dr. Kevin P. Campbell of the Howard Hughes Medical Institute at the University of Iowa College of Medicine.
"This confirms the role of calcium channels in mouse models for absence epilepsy," says Dr. Frankel. "Identification of the stargazer gene provides a new opportunity to better understand how these channels function in the mammalian brain and how they may be targeted in the treatment of neuroexcitability disorders, including epilepsy, in humans."
Epilepsy is a neurological disorder that affects approximately one percent of the U.S. population and has two major forms: absence (petit mal) and convulsive (grand mal). Absence seizures primarily occur in children and are characterized by brief lapses in consciousness during which the person appears to be staring into space. Convulsive seizures are more severe, typically lasting from 1 to 7 minutes, and involve loss of consciousness and motor control.
Although the complex mechanisms of epilepsy are still a mystery, the seizures are known to result from the misfiring of neurons in the brain. Instead of transmitting electrical impulses in an orderly manner, epileptic neurons fire all at once, creating a "storm" that disrupts normal brain function. Half of all human epilepsies are estimated to have a genetic basis, Dr. Frankel says.