Sudden death due to malignant hyperthermia with a mutation of RYR1: autopsy, morphology and genetic analysis.

Malignant hyperthermia (MH) is an autosomal dominant disorder characterized by abnormal calcium homeostasis in skeletal muscles in response to triggering agents. Autopsy, morphology, and genetic analysis were performed on a 19-year-old man who died rapidly after exposure to sevoflurane during maxillofacial surgery. Muscle spasm around the operation area and limb rigidity occurred and renal tubules full of myoglobin casts were observed by microscopy. Ultrastructural changes in the skeletal muscles and the myocardium were detected by transmission electron microscopy (TEM). Genetic analysis disclosed a ryanodine receptor type 1 (RYR1) gene mutation and a nucleoide mutation in chromosome 19q (G1021A) in the deceased and his father. According to the fore mentioned results, the relationship between the cause of death and MH was confirmed. Thus, genetic analysis can be an important procedure in diagnosing MH.