Rheumatoid arthritis is a painful and disabling autoimmune disease that affects more than 1% of people worldwide. In the United States alone, it disrupts the lives of about 1.

Researchers have been able to see what happens in inflamed joints of children with arthritis, giving insight into why treatments affect children differently.

Dr. Kimberly Trotter distilled four high-impact disease clusters—gout, rheumatoid arthritis (RA), systemic lupus ...