Isaac's syndrome is charachterized by K (potassium) channelopathy with muscle spasms and myokymia. It is diagnosed in early adulthood. It is mostly sporadic and underdiagnosed disorder. The patient came to our hospital because of muscle pains in arms and legs, weakness, concordance and muscle cramps which have continued for 20 days. The electromiyography of the patient shows myokymias. Because of rarity of Isaac's disease, we are discussing the diagnosis
