Understanding the causes and genetics of two rare inflammatory arthritis conditions

This is a research study designed to better understand two rare and serious inflammatory arthritis conditions: systemic juvenile idiopathic arthritis (which affects children under 16) and adult-onset Still's disease (which affects adults). Researchers will follow patients over time, collect blood and biological samples, and study the genetic and molecular factors that influence how these diseases develop and respond to treatment. The goal is to eventually develop better ways to diagnose these conditions earlier and predict which treatments will work best for each person.

These two conditions are poorly understood and are often diagnosed very late because there is no simple blood test for them. Doctors currently have no way to predict which patients will respond well to treatment or which patients are at risk for serious complications. This study will help researchers identify the genetic and biological causes of these diseases so that patients can receive faster, more accurate diagnoses and better personalized treatment plans.