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Novel CACNA1S mutation in hypokalaemic periodic paralysis
  1. Telma Luís1,
  2. Maria Inês Linhares2,
  3. Sónia Regina Silva1 and
  4. Filipa Rodrigues1,3
  1. 1Department of Pediatrics, Centro Hospitalar do Baixo Vouga EPE, Aveiro, Portugal
  2. 2Centro Hospitalar e Universitario de Coimbra EPE Hospital Pediatrico de Coimbra, Coimbra, Portugal
  3. 3Child Development Unit—Neuropediatrics, Department of Pediatrics, Centro Hospitalar do Baixo Vouga, Aveiro, Portugal
  1. Correspondence to Dr Maria Inês Linhares; inesrclinhares{at}


A 15-year-old girl was admitted to emergency department with an acute flaccid tetraparesis with no other symptoms. A history of recurrent similar episodes with spontaneous recovery was reported and no family history was known. Laboratory tests revealed severe hypokalaemia and hypokaluria. Symptoms resolution occurred after potassium replacement. The diagnosis of hypokalaemic periodic paralysis (HPP) was confirmed by genetic testing, which revealed a not previously described mutation in CACNA1S gene (c.3715C>G p.Arg1239Gly). HPP is a rare neuromuscular disorder that causes episodic attacks of flaccid paralysis with concomitant hypokalaemia. Primary forms of the disease are skeletal muscle ion channelopathies. HPP occurs due to a problem in potassium distribution rather than a total body potassium deficiency. Therefore potassium replacement should be carefully performed because of the risk of rebound hyperkalaemia. Knowing this rare entity is important in order to avoid diagnostic delays and so that proper treatment can be initiated to reduce morbidity and mortality.

  • paediatrics
  • muscle disease

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  • Contributors TL and MIL have participated in the concept, design and drafting of the manuscript. SRS and FR have participated in the drafting and reviewing of the manuscript. All authors have approved the manuscript as submitted.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Case reports provide a valuable learning resource for the scientific community and can indicate areas of interest for future research. They should not be used in isolation to guide treatment choices or public health policy.

  • Competing interests None declared.

  • Provenance and peer review Not commissioned; externally peer reviewed.