Immune cells constantly get new mutations. We do not know if these mutations cause autoimmune diseases like lupus, where the immune system attacks the body. In my early-stage research, I found hundreds of mutations in immune cells from children with lupus. I also created tools for studying how these mutations affect cells. The goal of this project is to understand how immune cells from children with diseases like lupus and arthritis are influenced by mutations. This project has three parts: First, I will identify mutations in immune cells. Second, I will study how these mutations affect the way DNA is organized in immune cells. Third, I will look at single immune cells to see how gene activity and cell behavior are related to mutations. This project will improve our knowledge of mutations in autoimmune diseases that affect children. Future studies will focus on specific important mutations identified in this project. These results will increase our understanding of autoimmune diseases and lead to better treatments.