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GTR Home > Conditions/Phenotypes > Malignant hyperthermia, susceptibility to, 5

Summary

Excerpted from the GeneReview: Malignant Hyperthermia Susceptibility
Malignant hyperthermia susceptibility (MHS) is a pharmacogenetic disorder of skeletal muscle calcium regulation associated with uncontrolled skeletal muscle hypermetabolism. Manifestations of malignant hyperthermia (MH) are precipitated by certain volatile anesthetics (i.e., halothane, isoflurane, sevoflurane, desflurane, enflurane), either alone or in conjunction with a depolarizing muscle relaxant (specifically, succinylcholine). The triggering substances cause uncontrolled release of calcium from the sarcoplasmic reticulum and may promote entry of extracellular calcium into the myoplasm, causing contracture of skeletal muscles, glycogenolysis, and increased cellular metabolism, resulting in production of heat and excess lactate. Affected individuals experience acidosis, hypercapnia, tachycardia, hyperthermia, muscle rigidity, compartment syndrome, rhabdomyolysis with subsequent increase in serum creatine kinase (CK) concentration, hyperkalemia with a risk for cardiac arrhythmia or even cardiac arrest, and myoglobinuria with a risk for renal failure. In nearly all cases, the first manifestations of MH (tachycardia and tachypnea) occur in the operating room; however, MH may also occur in the early postoperative period. There is mounting evidence that some individuals with MHS will also develop MH with exercise and/or on exposure to hot environments. Without proper and prompt treatment with dantrolene sodium, mortality is extremely high.

Available tests

38 tests are in the database for this condition.

Check Related conditions for additional relevant tests.

Genes See tests for all associated and related genes

  • Also known as: CACNL1A3, CCHL1A3, CMYO18, CMYP18, Cav1.1, DHPRM, HOKPP, HOKPP1, MHS5, TTPP1, hypoPP, CACNA1S
    Summary: calcium voltage-gated channel subunit alpha1 S

Clinical features

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Practice guidelines

  • ACMG ACT, 2019
    American College of Medical Genetics and Genomics, Genomic Testing (Secondary Findings) ACT Sheet, RYR1 and CACNA1S Pathogenic Variants (Malignant Hyperthermia), 2019
  • Orphanet, 2013
    Orphanet Emergency Guidelines: Malignant hyperthermia

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