Inheriting two genetic mutations that can individually cause epilepsy might actually be seizure-protective, said Baylor College of Medicine researchers in a report that appears online today in the journal Nature Neuroscience.
In the genetics of the brain, two wrongs can make a right, said Dr. Jeffrey L. Noebels, professor of neurology, neuroscience and molecular and human genetics at BCM. We believe these findings have great significance to clinicians as we move toward relying upon genes to predict neurological disease.
In addition, the finding might point the way to new ways of treating epilepsy using gene-directed therapy.
If you have a potassium channel defect, then a drug blocking certain calcium channels might also benefit you, said Noebels.
Noebels and his colleagues, who included first author Dr. Ed Glasscock, a post-doctoral researcher at BCM, 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 screen of people with non-familial seizure disorders being performed in collaboration with the Baylor Human Genome Sequencing Center.
One 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 brains temporal lobe, an area of the brain involved in processing sight, sound, speech and forming memories. It can also cause sudden death in young mice.
The other mutation is in a calcium channel gene (Cacna1a) that causes a specific type of seizure associated with absence epilepsy. When people suffer these seizures, they may appear to be staring into space and do not exhibit the jerking or movements generally associated with epilepsy.
When both types of mu
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Baylor College of Medicine