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Hyperkalemic periodic paralysis

Reviewed August 2013

What is hyperkalemic periodic paralysis?

Hyperkalemic periodic paralysis is a condition that causes episodes of extreme muscle weakness or paralysis, usually beginning in infancy or early childhood. Most often, these episodes involve a temporary inability to move muscles in the arms and legs. Episodes tend to increase in frequency until mid-adulthood, after which they occur less frequently. Factors that can trigger attacks include rest after exercise, potassium-rich foods such as bananas and potatoes, stress, fatigue, alcohol, pregnancy, exposure to cold temperatures, certain medications, and periods without food (fasting). Muscle strength usually returns to normal between attacks, although many affected people continue to experience mild stiffness (myotonia), particularly in muscles of the face and hands.

Most people with hyperkalemic periodic paralysis have increased levels of potassium in their blood (hyperkalemia) during attacks. Hyperkalemia results when the weak or paralyzed muscles release potassium ions into the bloodstream. In other cases, attacks are associated with normal blood potassium levels (normokalemia). Ingesting potassium can trigger attacks in affected individuals, even if blood potassium levels do not go up.

How common is hyperkalemic periodic paralysis?

Hyperkalemic periodic paralysis affects an estimated 1 in 200,000 people.

What genes are related to hyperkalemic periodic paralysis?

Mutations in the SCN4A gene can cause hyperkalemic periodic paralysis. The SCN4A gene provides instructions for making a protein that plays an essential role in muscles used for movement (skeletal muscles). For the body to move normally, these muscles must tense (contract) and relax in a coordinated way. One of the changes that helps trigger muscle contractions is the flow of positively charged atoms (ions), including sodium, into muscle cells. The SCN4A protein forms channels that control the flow of sodium ions into these cells.

Mutations in the SCN4A gene alter the usual structure and function of sodium channels. The altered channels stay open too long or do not stay closed long enough, allowing more sodium ions to flow into muscle cells. This increase in sodium ions triggers the release of potassium from muscle cells, which causes more sodium channels to open and stimulates the flow of even more sodium ions into these cells. These changes in ion transport reduce the ability of skeletal muscles to contract, leading to episodes of muscle weakness or paralysis.

In 30 to 40 percent of cases, the cause of hyperkalemic periodic paralysis is unknown. Changes in other genes, which have not been identified, likely cause the disorder in these cases.

Related Gene(s)

Changes in this gene are associated with hyperkalemic periodic paralysis.

  • SCN4A

How do people inherit hyperkalemic periodic paralysis?

This condition is inherited in an autosomal dominant pattern, which means one copy of the altered gene in each cell is sufficient to cause the disorder.

In most cases, an affected person has one parent with the condition.

Where can I find information about diagnosis or management of hyperkalemic periodic paralysis?

These resources address the diagnosis or management of hyperkalemic periodic paralysis and may include treatment providers.

  • Gene Review: Hyperkalemic Periodic Paralysis Type 1 (http://www.ncbi.nlm.nih.gov/books/NBK1496/)
  • Genetic Testing Registry: Familial hyperkalemic periodic paralysis (http://www.ncbi.nlm.nih.gov/gtr/conditions/C0238357)
  • Genetic Testing Registry: Hyperkalemic Periodic Paralysis Type 1 (http://www.ncbi.nlm.nih.gov/gtr/conditions/CN074266)
  • MedlinePlus Encyclopedia: Hyperkalemic Periodic Paralysis (http://www.nlm.nih.gov/medlineplus/ency/article/000316.htm)
  • Periodic Paralysis International: How is Periodic Paralysis Diagnosed? (http://hkpp.org/patients/do-i-have-pp)

You might also find information on the diagnosis or management of hyperkalemic periodic paralysis in Educational resources (http://www.ghr.nlm.nih.gov/condition/hyperkalemic-periodic-paralysis/show/Educational+resources) and Patient support (http://www.ghr.nlm.nih.gov/condition/hyperkalemic-periodic-paralysis/show/Patient+support).

General information about the diagnosis (http://ghr.nlm.nih.gov/handbook/consult/diagnosis) and management (http://ghr.nlm.nih.gov/handbook/consult/treatment) of genetic conditions is available in the Handbook. Read more about genetic testing (http://ghr.nlm.nih.gov/handbook/testing), particularly the difference between clinical tests and research tests (http://ghr.nlm.nih.gov/handbook/testing/researchtesting).

To locate a healthcare provider, see How can I find a genetics professional in my area? (http://ghr.nlm.nih.gov/handbook/consult/findingprofessional) in the Handbook.

Where can I find additional information about hyperkalemic periodic paralysis?

You may find the following resources about hyperkalemic periodic paralysis helpful. These materials are written for the general public.

You may also be interested in these resources, which are designed for healthcare professionals and researchers.

What other names do people use for hyperkalemic periodic paralysis?

  • adynamia episodica hereditaria
  • familial hyperkalemic periodic paralysis
  • Gamstorp disease
  • Gamstorp episodic adynamy
  • hyperKPP
  • hyperPP
  • primary hyperkalemic periodic paralysis

For more information about naming genetic conditions, see the Genetics Home Reference Condition Naming Guidelines (http://ghr.nlm.nih.gov/ConditionNameGuide) and How are genetic conditions and genes named? (http://ghr.nlm.nih.gov/handbook/mutationsanddisorders/naming) in the Handbook.

What if I still have specific questions about hyperkalemic periodic paralysis?

Ask the Genetic and Rare Diseases Information Center (http://rarediseases.info.nih.gov/GARD/).

What glossary definitions help with understanding hyperkalemic periodic paralysis?

autosomal ; autosomal dominant ; cell ; familial ; fasting ; gene ; hyperkalemia ; inherited ; ions ; ion transport ; muscle cells ; myotonia ; potassium ; protein ; sodium ; stress

You may find definitions for these and many other terms in the Genetics Home Reference Glossary (http://www.ghr.nlm.nih.gov/glossary).

References

  • Cannon SC. An expanding view for the molecular basis of familial periodic paralysis. Neuromuscul Disord. 2002 Aug;12(6):533-43. Review. (http://www.ncbi.nlm.nih.gov/pubmed/12117476?dopt=Abstract)
  • Fontaine B. Periodic paralysis. Adv Genet. 2008;63:3-23. doi: 10.1016/S0065-2660(08)01001-8. Review. (http://www.ncbi.nlm.nih.gov/pubmed/19185183?dopt=Abstract)
  • Gene Review: Hyperkalemic Periodic Paralysis Type 1 (http://www.ncbi.nlm.nih.gov/books/NBK1496/)
  • Jurkat-Rott K, Holzherr B, Fauler M, Lehmann-Horn F. Sodium channelopathies of skeletal muscle result from gain or loss of function. Pflugers Arch. 2010 Jul;460(2):239-48. doi: 10.1007/s00424-010-0814-4. Epub 2010 Mar 17. Review. (http://www.ncbi.nlm.nih.gov/pubmed/20237798?dopt=Abstract)
  • Jurkat-Rott K, Lehmann-Horn F. Genotype-phenotype correlation and therapeutic rationale in hyperkalemic periodic paralysis. Neurotherapeutics. 2007 Apr;4(2):216-24. Review. (http://www.ncbi.nlm.nih.gov/pubmed/17395131?dopt=Abstract)
  • Jurkat-Rott K, Lehmann-Horn F. Paroxysmal muscle weakness: the familial periodic paralyses. J Neurol. 2006 Nov;253(11):1391-8. Epub 2006 Nov 30. Review. (http://www.ncbi.nlm.nih.gov/pubmed/17139526?dopt=Abstract)
  • Miller TM, Dias da Silva MR, Miller HA, Kwiecinski H, Mendell JR, Tawil R, McManis P, Griggs RC, Angelini C, Servidei S, Petajan J, Dalakas MC, Ranum LP, Fu YH, Ptácek LJ. Correlating phenotype and genotype in the periodic paralyses. Neurology. 2004 Nov 9;63(9):1647-55. (http://www.ncbi.nlm.nih.gov/pubmed/15534250?dopt=Abstract)
  • Venance SL, Cannon SC, Fialho D, Fontaine B, Hanna MG, Ptacek LJ, Tristani-Firouzi M, Tawil R, Griggs RC; CINCH investigators. The primary periodic paralyses: diagnosis, pathogenesis and treatment. Brain. 2006 Jan;129(Pt 1):8-17. Epub 2005 Sep 29. Review. (http://www.ncbi.nlm.nih.gov/pubmed/16195244?dopt=Abstract)

 

The resources on this site should not be used as a substitute for professional medical care or advice. Users seeking information about a personal genetic disease, syndrome, or condition should consult with a qualified healthcare professional. See How can I find a genetics professional in my area? (http://ghr.nlm.nih.gov/handbook/consult/findingprofessional) in the Handbook.

 
Reviewed: August 2013
Published: August 25, 2014