<prompt> All of the following are calcium channelopathies, exceptEpisodic ataxia -1Spinocerebellar ataxia -6Familial hemiplegic migraineHypokalemic periodic paralysis  <response>: Clinical characteristics. Episodic ataxia type 1 EA1 is a potassium channelopathy characterized by constant myokymia and dramatic episodes of spastic contractions of the skeletal muscles of the head, arms, and legs with loss of both motor coordination and balance. EA1 may be associated with epilepsy. Ref Harrison20th edition pg 2234 