Abstract
Malignant hyperthermia (MH) in humans is an autosomal dominant disorder of skeletal muscle Ca2+-regulation. In MH-susceptible patients, a potentially lethal hypermetabolic reaction is triggered after exposure to volatile anesthetics and/or succinylcholine.
Central core disease (CCD) is an inherited congenital myopathy allelic to MH histologically characterized by degenerative central areas deprived of mitochondria along the full length of muscle fibers. CCD patients are regarded usually as MH-susceptible but, unlike other MH patients, they present with delayed motor milestones in infancy and hypotonia.
More than 50% of MH cases and almost all CCD cases are associated with mutations in the ryanodine receptor (RYR1) gene, which encodes for the major Ca2+ release channel in skeletal muscle sarcoplasmic reticulum. Most RYR1 mutations are clustered in (but not limited to) three “Hot Spots” near the gene regions of domain mamed the foot structure and Ca2+ release channel in the membrane of the sarcoplasmic reticulum, respectively. MH/CCD phenotype overlaps due to some mutations located in the first two hot spots, corresponding to the myoplasmic domain of the protein. However, most patients with typical CCD have mutations at the C-terminal region, which comprises the pore-forming domain. Although C-terminal mutations seemingly produce either MH or CCD phenotype, but not both, CCD patients must be considered to be MH-susceptible until proven otherwise.
