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Genetic and Rare Diseases Information Center (GARD)

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Hypokalemic periodic paralysis


Other Names for this Disease
  • HOKPP
  • HypoPP
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Your Question

Do you have more information about the prognosis for hypokalemic periodic paralysis? I have this condition and my son has it too. He has just become a father of a lovely baby boy. My son is also worried that he will have passed it on to his child.

Our Answer

We have identified the following information that we hope you find helpful. If you still have questions, please contact us.

What is the prognosis for hypokalemic periodic paralysis?

The prognosis for hypokalemic periodic paralysis varies among affected individuals. Although most people with this condition regain their muscle strength between attacks, repeated episodes can lead to persistent muscle weakness later in life.[1] Treatment may help prevent or even reverse progressive muscle weakness.[2]
Last updated: 4/20/2010

How is hypokalemic periodic paralysis inherited?

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.[1]
Last updated: 4/20/2010

How is hypokalemic periodic paralysis diagnosed?

The diagnosis of hypokalemic periodic paralysis is based on a history of episodes of paralysis and low levels of potassium in the blood during attacks (less than 0.9 to 3.0 mmol/L), but not between attacks. An important part of the diagnosis is to rule out other potential causes, including myotonia, hyperthyroidism, and arrhythmia. Affected individuals typically have a family history consistent with autosomal dominant inheritance.[3]

Genetic testing is available for hypokalemic periodic paralysis. Of all individuals meeting diagnostic criteria for this condition, approximately 55 to 70 percent have mutations in the CACNA1S gene, and approximately 8 to 10 percent have mutations in the SCN4A gene. GeneTests lists the names of laboratories that perform clinical genetic testing of the CACNA1S and SCN4A genes for hypokalemic periodic paralysis. When a disease-causing mutation is identified in an affected individual, genetic testing can be performed for at-risk, asymptomatic family members.

Please note:  Most of the laboratories listed through GeneTests do not accept direct contact from patients and their families; therefore, if you are interested in learning more, you will need to work with a health care provider or a genetics professional.  See below for a list of online resources that can assist you in locating a genetics professional near you.
Last updated: 4/20/2010

How can I find a genetics professional in my area?

Genetics clinics are a source of information for individuals and families regarding genetic conditions, treatment, inheritance, and genetic risks to other family members. More information about genetic consultations is available from Genetics Home Reference. To find a genetics clinic, we recommend that you contact your primary healthcare provider for a referral.

The following online resources can help you find a genetics professional in your community:

Last updated: 7/17/2013

References