Certain types of early-onset epilepsy are caused by previously unknown mutations of a potassium channel gene, KCNA2. The mutations disrupt the electrical balance in the brain in two ways. In some patients, the flow of potassium is greatly reduced; while in others, it is raised enormously. Both states can lead to hard-to-treat epileptic seizures. Mental and motor development can come to a stop, or even regress. These findings were made by a group of European scientists led by researchers at the Universities of Leipzig and Tübingen in Germany. Their results were published online on March 9, 2015 in Nature Genetics. The article is titled “De Novo Loss- or Gain-of-Function Mutations in KCNA2 Cause Epileptic Encephalopathy.” Among what the brain needs in order to function is the interaction of many different ion channels, which regulate electrical signals by keeping a delicate balance between the influences which make cells rest or become excited. The ion channels are located in the cell wall of a neuron, together with many other pores and channels. “The potassium channel KCNA2 is one of many channels. It regulates the flow of potassium ions by opening and shutting, thereby also regulating the electrical excitability of the neurons in the brain,” explains Professor Johannes Lemke, head of Leipzig University Hospitals’ Institute of Human Genetics. Mutations in various ion channels are one of the main causes of epilepsy. “That is why identifying each mutation in the ion channel is important for diagnosing the individual epilepsy syndrome and finding ways of treating it,” says Professor Holger Lerche, of Tübingen’s Hertie Institute for Clinical Brain Research (HIH) and medical director of Neurology and Epileptology at the Tübingen University Hospitals.
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