Potassium. The channelopathies are the largest group of genetic epilepsies, and disease-causing variants in genes for neuronal sodium channels, calcium channels, and potassium channels are among the most common causes of genetic epilepsies. However, amongst the various ion channel families, potassium channels stand out due to sheer number. There are more than 70 potassium channel genes encoded in the human genome, and the combination of various subtypes and auxiliary units generates an enormous combinatorial potential. In a recent publication, de novo variants in KCNA6, the gene for the voltage-gated potassium channel Kv1.6, were identified in childhood-onset neurodevelopmental disorders. Here is the somewhat unusual story of the most recent potassium channel gene implicated in human epilepsy. Continue reading