SNP Shot: Genomic Insights

Malignant hyperthermia (MH) is a dangerous reaction to specific anesthetic medications commonly used during surgical and other invasive procedures. This reaction is triggered by certain anesthetic gases, which numb pain, either alone or combined with muscle relaxants that temporarily paralyze patients during surgery. Individuals susceptible to MH, when exposed to these drugs, may experience a rapid increase in heart rate, high body temperature (hyperthermia), rapid breathing, muscle stiffness, muscle breakdown (rhabdomyolysis), and increased acidity in the blood and tissues (acidosis). If untreated and the triggering drugs are continued, this reaction can lead to organ failure, including heart failure (cardiac arrest), kidney failure (renal failure), and a blood clotting disorder called disseminated intravascular coagulation. These complications can be fatal. (In medical terminology, "malignant" signifies a health-threatening condition.)

Individuals with an elevated risk for MH are considered to have malignant hyperthermia susceptibility (MHS). Many affected individuals are unaware of their condition until they experience a severe anesthetic reaction during surgery or undergo testing, often prompted by a family history of severe reactions. MH does not necessarily occur with every anesthetic exposure. Many individuals who experience a severe reaction have previously tolerated the triggering drugs without incident.

Susceptible individuals may also be at risk for "awake" malignant hyperthermia. In this variant, the severe reaction occurs in response to physical exertion, often during illness, rather than from triggering medications.

While MH frequently occurs in otherwise healthy individuals, certain inherited muscle disorders, such as central core disease, multiminicore disease, and STAC3 disorder, are linked to malignant hyperthermia susceptibility.

Inheritance:

Malignant hyperthermia susceptibility typically follows an autosomal dominant inheritance pattern. This means that inheriting just one copy of the altered gene in each cell is enough to increase the risk of a severe reaction to specific surgical anesthetics. In most cases, the affected person inherits the altered gene from a parent who is also at risk for the condition.