KCNA2 and Epileptic encephalopathy: Mutations causing either gain- or loss-of-function phenotypes of Kv1.2 have been linked to epileptic encephalopathy and ataxia27, 32, 33, and there is a notable low frequency of predicted loss-of-function Kv1.2 mutants (along with Kv1.4) in exome aggregation databases (ExAC consortium)34.