NEJM This Week — February 6, 2025

Featuring articles on IgA nephropathy, a treatment in children with obesity, NRG1 fusion–positive cancer, a case of a T-cell lymphoma, and the discovery of GLP-1–based drugs; a review article on hemophagocytic lymphohistiocytosis, a Clinical Problem-Solving on traveling companions; and Perspectives on cell and gene therapies, on gender-affirming care, and on the man who lives in the cardboard box.