**Autosomal Recessive Polycystic Kidney Disease (ARPKD)** is a rare condition where kidneys develop many cysts, leading to kidney problems. This study looks at ARPKD and related diseases like *Joubert syndrome* and *Caroli syndrome*. The aim is to create a big database with medical and genetic information to help doctors and families understand these diseases better.

Participants won't need to visit the clinic. Instead, we collect their past, current, and future medical information. We might ask for a blood sample, about a teaspoon, from the participant and their parents. If blood isn’t possible, saliva can be used. Samples go to Children's Hospital of Philadelphia for processing and storage. If you donate tissue (like from kidney or liver), it will help researchers study these diseases.

**Key Points:**

• **No clinic visits needed:** We use your medical history and home samples.
• **Data privacy:** Your personal information is kept private with unique codes.
• **Tissue and DNA samples:** Help researchers make new discoveries about these diseases.