The study checks if a medicine called **guselkumab** is safe for kids who have certain health issues. These issues include ulcerative colitis (which means the inside of the large intestine is swollen), Crohn's disease (a condition causing pain in the digestive system), or juvenile psoriatic arthritis (joint pain with skin problems). The medicine is given through a shot under the skin.

• The study is for those who have already been taking guselkumab and found it helpful.
• Participants should not be planning to have a baby during the study.
• Participants must be under 18 years unless the medicine has been available for two years in their country.

Before joining, doctors and parents must agree that it’s safe and beneficial for the child. If you’re 7 or older, you should also agree to join. The study is meant to ensure long-term safety and effectiveness of the medicine in kids. It’s important to talk to your doctor if you think this study might be right for you.