Malignant Hyperthermia NGS panel

Genes
(full coding
region):		 CACNA1S, RYR1, STAC3
Lab method: NGS panel with CNV analysis
TAT: 6-9 weeks
Specimen requirements: 2-4 ml of blood with anticoagulant EDTA

1 µg DNA in TE, AE or pure sterile water at 100-250 ng/µl
The A260/A280 ratio should be 1.8-2.0. DNA sample should be run on an agarose gel as a single band, showing no degradation, alongside with a quantitative DNA marker.
Ordering information: Go to online ordering or download sample submission form

Indications for genetic testing:

  1. Clinical episode of malignant hyperthermia (MH)
  2. Positive caffeine/halothane contracture test
  3. Relative with a positive contracture test or a known MH-causing variant
  4. Unexplained death with signs of MH during or immediately after anesthesia
  5. Exercise-related rhabdomyolysis and/or heat stroke

Malignant hyperthermia is an inherited pharmacogenetic disorder of calcium regulation resulting in uncontrolled skeletal muscle hypermetabolism.

Manifestations of MH are triggered by certain volatile anesthetics (i.e. halothane, isoflurane, sevoflurane, desflurane, enflurane), either alone or in conjunction with succinylcholine, a depolarizing muscle relaxant. The triggering substances initiate 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.

MH clinical manifestations are hyperthermia, hypercapnia, tachycardia, acidosis, muscle rigidity, compartment syndrome, rhabdomyolysis with subsequent increase in serum creatine kinase 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 occur in the operating room, MH may also occur in the early postoperative period. Recent studies show that some individuals with MH will also develop the disorder with exercise and/or on exposure to hot environments. Without prompt treatment with dantrolene sodium, mortality is extremely high.

MH is an autosomal dominant disorder.

References:

Riazi S, Kraeva N, Hopkins PM. Updated guide for the management of malignant hyperthermia. Can J Anaesth. 2018;65:709–21.
Rosenberg H et al. Malignant Hyperthermia Susceptibility. GeneReviews® Initial Posting: December 19, 2003; Last Update: January 16, 2020.
Rosenberg H, Pollock N, Schiemann A, Bulger T, Stowell K. Malignant hyperthermia: A review. Orphanet J Rare Dis. 2015;10:93.