This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: C.N.S, Subject name: Medicine
[{'content': 'All of the following are calcium channelopathies, except \nSelect and explain. \nA. Episodic ataxia -1, B. Spinocerebellar ataxia -6, C. Familial hemiplegic migraine, D. Hypokalemic periodic paralysis', 'role': 'user'}, {'content': 'Answer: A \nExplanation: 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', 'role': 'assistant'}]