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Medline ® Abstract for Reference 29

of 'Hyperkalemic periodic paralysis'

Normokalemic periodic paralysis revisited: does it exist?
Chinnery PF, Walls TJ, Hanna MG, Bates D, Fawcett PR
Ann Neurol. 2002;52(2):251.
Normokalemic periodic paralysis (normoKPP) is well established in the literature, but there are doubts as to whether it exists as a discrete entity. Retrospective clinical and molecular analysis has confirmed suspicions that most normoKPP families actually have a variant of hyperkalemic periodic paralysis (hyperKPP) due to a mutation of the muscle-specific sodium channel gene (SCN4A). However, the original normoKPP family described by Poskanzer and Kerr (Poskanzer DC, Kerr DNS. A third type of periodic paralysis, with normokalemia and favourable response to sodium chloride. Am J Med 1961;31:328-342) has remained unchallenged. We identified the Met1592Val mutation of SCN4A in an affected descendent of this original normoKPP family. This is the final piece in the puzzle: normoKPP is actually a variant of hyperKPP and is not a distinct disorder.
Department of Neurology, University of Newcastle Upon Tyne, Newcastle Upon Tyne, United Kingdom. P.F.Chinnery@ncl.ac.uk