The importance of gene variants in the IFN signaling pathway for SLE susceptibility was shown already in 2005, when we together with professor Ann-Christine Syvänen in a candidate gene study described the association between SLE and IFN regulatory factor 5 (IRF5) and tyrosine kinase 2 (TYK2) (64). The gene discussed is TYK2; the disease is systemic lupus erythematosus.