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What is malignant hyperthermia, and how can you find out if you may be at risk?

For most people, anesthesia is a safe and important part of surgery or other types of procedures. But for a small group of people, anesthesia could cause a potentially life threatening condition known as malignant hyperthermia. Because this condition is genetic, patients are usually asked a series of questions about their family’s medical history before undergoing surgery. But for people who don’t know their family history, such questions might not be helpful. DNA sequencing can help doctors prescribe anesthetic plans that are safe.

Learn about a Mayo Clinic patient who used genetic testing to gain insights into his potential health risks.

Malignant hyperthermia is a condition where a person’s body begins to overheat in a life-threatening way, most often as a response to inhaled anesthetics. In this response, a genetic abnormality in muscle cells results in sustained muscle contractions and an increase in metabolism. In turn, this can lead to a spike in body temperature and increased blood acid levels that can cause significant damage to the body and its organs. If this goes unnoticed and untreated, the results can be deadly. Modern medical practices and advanced technology have made it possible to test individuals who may be at risk of malignant hyperthermia. With this knowledge, anesthesia providers can prescribe anesthesia plans that can avoid this problem.
Research into the disease has learned what causes this type of sensitivity and how to identify people who are at risk—before they experience life-threatening symptoms. Such efforts have shown us that family history and genetics play an important role.
Variants have been discovered that affect two genes which may predispose a person to malignant hyperthermia. Most people who experience malignant hyperthermia (~70-80% of patients) have variants in the RYR1 gene (a smaller group of people have variants in the CACNA1S gene).
Estimates about how many people experience malignant hyperthermia vary, but studies suggest that one in every 2,000 people may be at risk. Identifying these individuals can be helpful so that they—and their medical providers—know to avoid trigger substances. Mayo Clinic GeneGuide™, available from Helix, analyzes your DNA to determine if you are genetically predisposed to a number of conditions—including malignant hyperthermia. The product also includes educational information and support from a genetic counselor to help people understand their results.

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Mayo Clinic GeneGuide™ >