Malignant hyperthermia: Molecular defects in membrane permeability

Summary Malignant hyperthermia (MH), a genetically inherited disorder of skeletal muscle, is due to molecular defect in membrane permeability. The alteration in membrane permeability is suggested to be due to enhanced phospholipase A₂ activity which is responsible for the increased level in sarcoplasmic Ca²⁺. The excess Ca²⁺ is responsible for muscle hyper-rigidity and enhanced rate of glycolysis, resulting in a rapid rate of lactic acid production and a low pH in MH muscle.