Genes encoding potassium channels have been frequently reported in epilepsy and ataxia syndromes, including KCNQ2/KCNQ3 in benign familial neonatal convulsion syndromes [16, 17], KCNCI in progressive myoclonus epilepsy [18], KCNQ2 in epileptic encephalopathy syndromes [19], KCNA1 in episodic ataxia type 1 [20], KCNC3 in SCA13 [21] and recently myoclonic epilepsy and ataxia in KCNA2 [22]. Here, KCNQ3 is linked to cerebellar ataxia.