As early as 3 weeks after pristane injection, THX mice developed a malar rash evocative of the ‘butterfly rash’ in individuals with systemic lupus erythematosus (SLE), concomitant with rising levels of serum huIgG and huIgA, including antinuclear, anti-dsDNA, anti-histone, anti-Sm/anti-RNP and anti-RNA huIgG autoantibodies, eventually leading to kidney glomerular huIgG deposition and immunopathology (Fig. 8a,b). The gene discussed is RNPC3; the disease is systemic lupus erythematosus.