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Normokalemic periodic paralysis is not a distinct disease
Author(s) -
Song YoungWha,
Kim SungJo,
Heo TaeHwe,
Kim ManHo,
Kim JuneBum
Publication year - 2012
Publication title -
muscle and nerve
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.025
H-Index - 145
eISSN - 1097-4598
pISSN - 0148-639X
DOI - 10.1002/mus.23441
Subject(s) - periodic paralysis , hyperkalemia , paralysis , medicine , phenotype , channelopathy , disease , hypokalemic periodic paralysis , clinical phenotype , mutation , muscle disease , genetics , gene , biology , surgery
Recent molecular studies of the original cases of normokalemic periodic paralysis (normoKPP) have raised suspicions that these families actually had hyperkalemic periodic paralysis (hyperKPP) due to mutations in the skeletal muscle sodium channel gene SCN4A . However, there is still a debate about the existence of normoKPP. Methods: We screened 230 individuals with primary periodic paralysis for mutations in the SCN4A , CACNA1S , and KCNJ2 genes. All patients had either a hyperKPP or a hypoKPP phenotype, and none had a normoKPP phenotype. Results: In 4 hyperKPP patients from 2 families, molecular analyses revealed Arg675Gly and Arg675Gln mutations of SCN4A , which were previously reported to cause normoKPP. Each patient exhibited the characteristic clinical and laboratory features (including hyperkalemia during spontaneous attacks) of hyperKPP. Conclusion: Our findings support the notion that normoKPP is not a distinct disease. Muscle Nerve, 2012