A Multicenter Screening Study to Characterize the Prevalence of the KIT D816V Mutation in Patients With Suspected Clonal Mast Cell Disease

Key Inclusion Criteria: * Cohort 1 participants must meet inclusion criteria for either SMAC-A or SMAC-B: 1\. SMAC-A * Documented anaphylaxis due to Hymenoptera venom with cardiovascular symptoms or * History of at least one event of anaphylaxis as determined by the Investigator's clinical assessment and judgment based on available medical history, clinical presentation, and supporting documentation without a clearly identifiable trigger(s) or allergen(s) (otherwise idiopathic anaphylaxis) OR * SMAC-AGS: History of anaphylaxis after eating mammalian meat (e.g. pork, beef) AND history of el…