MAS825 Trial for NLRC4-GOF

The purpose of this study is to find out if the study drug, MAS825, iseffective in preventing flares and safe for children with NLRC4-Gain ofFunction (GOF). Researchers will also be testing how the body processes a drug by measuringhow quickly the drug is absorbed by the body, how quickly it is broken down bythe body, and how long it remains in the body (pharmacokinetics). Subjects willbe asked to come into the Rheumatology clinic for blood and stool testing,physical exam, an electrocardiogram (ECG), questionnaire completion, andadministration of study drug. Participation will last for up to 4 years.