RYR1 Variant clinical trials

Multisystem Features of Malignant Hyperthermia or Rhabdomyolysis Related to RYR1 Variants

Rationale: Malignant hyperthermia and rhabdomyolysis are phenotypes that have long been considered to occur only in response to external stimuli (trigger anaesthesia and physical exhaustion) show several features of a continuous disease manifestation. Previous studies showed prolonged bleeding time after injury, selective immunological advantages, axial muscle weakness and several social difficulties. A detailed study of the neuromuscular and multisystem features of patients with RYR1-related malignant hyperthermia or rhabdomyolysis is needed to provide clarification about the continuous and multisystem disease manifestations in these patients. Objective: Primary Objective: There are three primary objectives in this study. 1. To investigate the neuromuscular involvement of RYR1 related MH and rhabdomyolysis. 2. To investigate the immunological changes in subjects with RYR1 related MH and rhabdomyolysis. 3. To identify multisystem features of RYR1 related MH and rhabdomyolysis. There are no secondary objectives. Study design: The design of the study will be a clinical, open, observational study. The study consists of three parts; a clinical, imaging and immunological part. Study population: Patients with a history of malignant hyperthermia susceptibility (MHS), and/or a history of rhabdomyolysis related to a variant in RYR1. Intervention (if applicable): Not applicable. Main study parameters/endpoints: The study consists of three parts. Each part has it's own main study parameters 1. Clinical part: the results of the questionnaire study compared to standardizes normal values and the results of the comprehensive clinical assessment. 2. Imaging part: fatty infiltration and hypertrophy of proximal and axial muscles. 3. Immunological part: circulating and leukocyte released anti- and pro-inflammatory cytokine levels compared to healthy age and sex matched controls.