New research suggests that inheriting two genetic mutations that can individually cause epilepsy might actually reduce the number of seizures. The study, by researchers from Baylor College of Medicine, has been published in the journal Nature Neuroscience. Lead author Dr Jeffrey Noebels found that if someone has a potassium channel defect, then a drug blocking certain calcium channels might benefit them.
The researchers tested this hypothesis by breeding mice with two defective genes that govern ion channels, tiny pores in cells that allow molecules such as potassium and calcium to flow in and out. The genes were known to cause epilepsy when inherited singly within families. They have also been found in a large-scale screening of people with seizure disorders that have not been inherited. One genetic defect is a mutation in the Kcna1 gene involved in the channel that allows potassium to flow in and out of the cell. It causes severe seizures affecting the brain’s temporal lobe.
The other mutation is in a calcium channel gene that causes a specific type of seizure associated with absence epilepsy. When both types of mutation occurred in the same young mouse, that animal had dramatically reduced seizures. Dr Noebels commented: "Rather than screening for 'bad' genes one at a time, it may be essential to create a complete profile of many or even all genes in order to accurately assess the true genetic risk of any single defect in many common disorders such as epilepsy.
Fortunately, this amount of background information will soon become routinely obtainable in individual patients thanks to rapid technological progress in the field of neurogenomics. “We believe these findings have great significance to clinicians as we move toward relying upon genes to predict neurological disease.”