Normokalemic periodic paralysis revisited: does it exist?

PF Chinnery, TJ Walls, MG Hanna, D Bates… - Annals of …, 2002 - Wiley Online Library
PF Chinnery, TJ Walls, MG Hanna, D Bates, PRW Fawcett
Annals of neurology, 2002Wiley Online Library
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 …
Abstract
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.
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