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Disease Profile

Familial periodic paralysis

Prevalence estimates on Rare Medical Network websites are calculated based on data available from numerous sources, including US and European government statistics, the NIH, Orphanet, and published epidemiologic studies. Rare disease population data is recognized to be highly variable, and based on a wide variety of source data and methodologies, so the prevalence data on this site should be assumed to be estimated and cannot be considered to be absolutely correct.


US Estimated

Europe Estimated

Age of onset





Autosomal dominant A pathogenic variant in only one gene copy in each cell is sufficient to cause an autosomal dominant disease.


Autosomal recessive Pathogenic variants in both copies of each gene of the chromosome are needed to cause an autosomal recessive disease and observe the mutant phenotype.


dominant X-linked dominant inheritance, sometimes referred to as X-linked dominance, is a mode of genetic inheritance by which a dominant gene is carried on the X chromosome.


recessive Pathogenic variants in both copies of a gene on the X chromosome cause an X-linked recessive disorder.


Mitochondrial or multigenic Mitochondrial genetic disorders can be caused by changes (mutations) in either the mitochondrial DNA or nuclear DNA that lead to dysfunction of the mitochondria and inadequate production of energy.


Multigenic or multifactor Inheritance involving many factors, of which at least one is genetic but none is of overwhelming importance, as in the causation of a disease by multiple genetic and environmental factors.


Not applicable


Other names (AKA)

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] 


Support and advocacy groups can help you connect with other patients and families, and they can provide valuable services. Many develop patient-centered information and are the driving force behind research for better treatments and possible cures. They can direct you to research, resources, and services. Many organizations also have experts who serve as medical advisors or provide lists of doctors/clinics. Visit the group’s website or contact them to learn about the services they offer. Inclusion on this list is not an endorsement by GARD.

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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.
        • Orphanet is a European reference portal for information on rare diseases and orphan drugs. Access to this database is free of charge.


          1. Rubin M. Familial Periodic Paralysis. Merck Manual Consumer Version. 2017; https://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; https://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; https://emedicine.medscape.com/article/1171678-overview.