Identification of malignant hyperthermia-susceptible ryanodine receptor type 1 gene (RYR1) mutations in a child who died in a car after exposure to a high environmental temperature

• Published in: Legal medicine (Tokyo, Japan) Vol. 11; no. 3; pp. 142 - 143
• Main Authors: Nishio, Hajime, Sato, Takako, Fukunishi, Shinya, Tamura, Akiyoshi, Iwata, Misa, Tsuboi, Kento, Suzuki, Koichi
• Format: Journal Article
• Language: English
• Published: Ireland Elsevier Ireland Ltd 01.05.2009
• Subjects: Automobiles; Autopsy; Child, Preschool; Fatal Outcome; Female; Genetic analysis; Genetic Predisposition to Disease; Heat stroke; Hot Temperature; Humans; Infant; Internal Medicine; Japan; Malignant Hyperthermia - genetics; Mutation; Ryanodine Receptor Calcium Release Channel - genetics; Temperature; Japan; Infant; Temperature; Autopsy; Genetic analysis; Heat stroke
• ISSN: 1344-6223; 1873-4162
• DOI: 10.1016/j.legalmed.2008.12.004

Abstract Malignant hyperthermia (MH) is a genetic disorder of skeletal muscle in susceptible individuals that is triggered by exposure to anesthetic agents, and can cause death. Mutations in the ryanodine receptor type 1 gene (RYR1) are associated with MH-susceptibility. MH is also triggered in susceptible individuals by severe exercise in hot conditions or by overheating in infants. Here, we report a case of a child, 2 years, 9 months of age, who was left in a car and exposed to a high environmental temperature. The child was suspected to have died of heat stroke by autopsy examinations. Postmortem mutation analysis revealed that the child possessed two distinct RYR1 mutations. Since each mutation had previously been identified in a separate MH-susceptible patient, MH-susceptibility with over-response to the environmental high temperature might have occurred in this child with RYR1 mutations. These findings suggest that a MH-susceptible case may have died with a presumed diagnosis of heat stroke at autopsy.