Of these, a dominantly inherited de novo missense mutation in KCNC1 (c.959 G > A, p.R320H), which encodes the voltage‐gated potassium channel (VGKC) KV3.1, causes PME with ataxia (myoclonus epilepsy and ataxia due to potassium channel mutation [MEAK]; Online Mendelian Inheritance in Man database [OMIM] # 616187).4, 5. This evidence concerns the gene KCNA3 and cerebellar ataxia.