National Center for Advancing and Translational Sciences Genetic and Rare Diseases Information Center, a program of the National Center for Advancing and Translational Sciences

Familial periodic paralysis

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Other Names:
Genetic periodic paralysis
Familial periodic paralysis is a disease characterized by sudden attacks of weakness and paralysis. Weakness is recurrent, affecting mainly the limbs, and is often brought on by exercising or eating too many or too few carbohydrates.[1] There are 4 forms of familial periodic paralysis: hypokalemic, hyperkalemic, thyrotoxic, and Andersen-Tawil syndrome. In the hypokalemic form, the paralysis is caused by low levels of potassium. In the hyperkalemic form, the paralysis is caused by high levels of potassium in the blood. In the thyrotoxic form, the paralysis is caused by low levels of potassium in the blood and an overactive thyroid gland (hyperthyroidism). In Andersen-Tawil syndrome, potassium levels can be high, low, or normal.[1][2] Mutations in the CACNA1S and SCN4A genes cause hypokalemic periodic paralysis.[3] The hyperkalemic form is due to mutations in SCN4A gene.[4] The underlying cause of the thyrotoxic form is unknown. Mutations in the KCNJ2 gene cause Andersen-Tawil syndrome.[5] Treatment is focused on correcting the levels of potassium in the blood and preventing episodes with lifestyle changes.[6] 
Last updated: 7/13/2017

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These resources provide more information about this condition or associated symptoms. The in-depth resources contain medical and scientific language that may be hard to understand. You may want to review these resources with a medical professional.

In-Depth Information

  • The Monarch Initiative brings together data about this condition from humans and other species to help physicians and biomedical researchers. Monarch’s tools are designed to make it easier to compare the signs and symptoms (phenotypes) of different diseases and discover common features. This initiative is a collaboration between several academic institutions across the world and is funded by the National Institutes of Health. Visit the website to explore the biology of this condition.
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  1. Rubin M. Familial Periodic Paralysis. Merck Manual Consumer Version. 2017; http://www.merckmanuals.com/home/children-s-health-issues/muscular-dystrophies-and-related-disorders/familial-periodic-paralysi.
  2. Rubin M. Familial Periodic Paralysis. Marck Manuals. Professional Version. 2017; http://www.merckmanuals.com/professional/pediatrics/inherited-muscular-disorders/familial-periodic-paralysis.
  3. Hypokalemic periodic paralysis. Genetics Home Reference. 2007; https://ghr.nlm.nih.gov/condition/hypokalemic-periodic-paralysis.
  4. Hyperkalemic periodic paralysis. Genetics Home Reference. 2013; https://ghr.nlm.nih.gov/condition/hyperkalemic-periodic-paralysis#genes.
  5. Andersen-Tawil syndrome. Genetics Home Reference. 2006; https://ghr.nlm.nih.gov/condition/andersen-tawil-syndrome.
  6. Sripathi N. Periodic Paralyses. Medscape Reference. May 18, 2017; http://emedicine.medscape.com/article/1171678-overview.