Abstract
BACKGROUND AND OBJECTIVES: Primary hypokalemic periodic paralysis (HypoPP) is an inherited channelopathy most commonly caused by mutations in CACNA1S. HypoPP can present with different phenotypes: periodic paralysis (PP), permanent muscle weakness (PW), and mixed weakness (MW) with both periodic and permanent weakness. Little is known about the natural history of HypoPP.
METHODS: In this 3-year follow-up study, we used the MRC scale for manual muscle strength testing and whole-body muscle MRI (Mercuri score) to assess disease progression in individuals with HypoPP-causing mutations in CACNA1S.
RESULTS: We included 25 men (mean age 43 years, range 18-76 years) and 12 women (mean age 42 years, range 18-76 years). Two participants were asymptomatic, 21 had PP, 12 MW, and two PW. The median number of months between baseline and follow-up was 42 (range 26-52). Muscle strength declined in 11 patients during follow-up. Four of the patients with a decline in muscle strength had no attacks of paralysis during follow-up, and two of these patients had never had attacks of paralysis. Fat replacement of muscles increased in 27 patients during follow-up. Eight of the patients with increased fat replacement had no attacks of paralysis during follow-up, and two of these patients had never had attacks of paralysis.
DISCUSSION: The study demonstrates that HypoPP can be a progressive myopathy in both patients with and without attacks of paralysis.
Original language | English |
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Journal | Journal of Neurology |
Volume | 270 |
Issue number | 12 |
Pages (from-to) | 6057-6063 |
Number of pages | 7 |
ISSN | 0340-5354 |
DOIs | |
Publication status | Published - Dec 2023 |
Keywords
- Adolescent
- Adult
- Aged
- Female
- Follow-Up Studies
- Humans
- Hypokalemic Periodic Paralysis/genetics
- Male
- Middle Aged
- Muscle Weakness
- Mutation/genetics
- Paralysis
- Young Adult
- Whole-body muscle MRI
- Hypokalemic periodic paralysis
- Permanent muscle weakness
- Myopathy