Objective Hypokalemic periodic paralysis (HypoKPP) is characterized by episodic flaccid paralysis of muscle and acute hypokalemia.The non-familial form of HypoKPP is consisted of thyrotoxic periodic paralysis (TPP) and sporadic periodic paralysis (SPP).The prevalence of HypoKPP is not low in China.Mutations in KCNJ18, which encodes the skeletal muscle-specific inwardly rectifying potassium channel Kir2.6, have been reported in some TPP and SPP.In the present study, we aim to identify whether the mutation of this KCNJ18 gene can be found in Chinese SPP.