In this issue of Rheumatic Disease Clinics, guest editor Dr. Erin Janssen brings her considerable expertise to the topic of New and Emerging Rheumatic Diseases. Top experts in the field cover issues such as approach to diagnosing in-born errors of immunity; Type I interferonopathies; SOCS1 and immune dysregulation; manifestations of DADA2; COPA syndrome; and more. Contains 15 relevant, practice-oriented topics including T cell tolerance/Treg defects; gene defects in early onset IBD/colitis; autoimmunity with cytoskeletal d/o - WAS, DOCK8; autoimmune and autoinflammatory neurologic conditions; genes in HLH and that predispose to MAS; mutations in severe COVID/MISC; and more. Provides in-depth clinical reviews on new and emerging rheumatic diseases, offering actionable insights for clinical practice. Presents the latest information on this timely, focused topic under the leadership of experienced editors in the field. Authors synthesize and distill the latest research and practice guidelines to create clinically significant, topic-based reviews.