Dominantly inherited malignant hyperthermia (MH) in the King-Denborough syndrome.

A 14-year-old boy, an only child, with the phenotypical dysmorphic features of the King-Denborough Syndrome developed a severe hyperthermic episode during anesthesia which responded to the administration of sodium dantrolene. As adequate metabolic studies were not available at the time of the crisis he was referred for confirmation of the malignant hyperthermia (MH) status. Muscle tension studies confirmed the presence of MH. The patient's mother and father were subsequently tested and the mother was found to be MH positive, the father MH negative.