Multiple pterygium-malignant hyperthermia syndrome

Multiple pterygium-malignant hyperthermia syndrome is an extremely rare genetic disorder characterized by the combination of multiple pterygia (webbing of skin across joints) and susceptibility to malignant hyperthermia, a life-threatening reaction to certain anesthetic agents. The condition affects the musculoskeletal system prominently, with features including multiple joint contractures (arthrogryposis), pterygia of the neck, axillae, elbows, and knees, short stature, and skeletal anomalies such as vertebral fusion and scoliosis. Facial features may include a distinctive appearance with downslanting palpebral fissures and micrognathia. The underlying pathology involves abnormalities of skeletal muscle that predispose affected individuals to malignant hyperthermia episodes when exposed to volatile anesthetic agents or depolarizing muscle relaxants such as succinylcholine. Malignant hyperthermia susceptibility is the most clinically dangerous aspect of this syndrome, as unrecognized exposure to triggering agents during surgery can lead to rapid and potentially fatal hyperthermia, muscle rigidity, rhabdomyolysis, metabolic acidosis, and multi-organ failure. The condition has been linked to mutations in the ryanodine receptor gene (RYR1), which encodes a calcium release channel in skeletal muscle. This gene is also implicated in other forms of malignant hyperthermia susceptibility and certain congenital myopathies. There is no cure for this syndrome. Management focuses on avoidance of triggering anesthetic agents, use of non-triggering anesthesia protocols when surgery is required, and availability of dantrolene (the specific antidote for malignant hyperthermia) in any surgical setting. Orthopedic management of contractures and pterygia may include physical therapy and, in some cases, surgical release. Genetic counseling is recommended for affected families. All individuals with this diagnosis should carry medical alert identification regarding their malignant hyperthermia susceptibility.

Data sourced from FDA regulatory filings and ClinicalTrials.gov. Updated periodically.

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