Upadacitinib is a selective Janus kinase 1 (JAK1) inhibitor that blocks signaling through multiple cytokine pathways involved in SLE pathogenesis, including type I and II interferons and the interleukins IL-2, IL-4, IL-6, IL-10, and IL-15. The gene discussed is JAK1; the disease is systemic lupus erythematosus.