Mutations in SCN4A gene exists in two Chinese patients with normokalemic periodic paralysis

Objective In this report are analysis two unrelated patients with typical normokalemic periodic paralysis(NormoKPP) features and the results of screenig the SCN4A gene for the disease related mutation.Methods Total genomic DNA was extracted from the peripheral blood leukocytes from two sporadic cases with NormoKPP and 50 unaffected controls subjects.Polymerase chain reaction(PCR) and direct DNA sequencing were used to detect 24 exons of SCN4A mutations.Results No causative mutations in the SCN4A gene were found in two sporadic cases with NormoKPP.However,six SCN4A gene polymorphisms were identified,864 CT(N288N),1570AG(S524G),2289CT(I763I),4126AG(N1376D),4539CT(I1513I) and 4869AG(T1623T),in some patients and controls.Conclusion Mutations in the SCN4A gene is not major cause of NormoKPP in the two patients in the study.