The most common clinical manifestation of cSLE at disease onset in our cohort included arthritis (62%), fever (52%), leukopenia (40%) and proteinuria (39%) while the most common immunological parameters included ANA (89%), dsDNA (64%), and low complements (C3 and C4) (44%) at first visit, first year and last assessment respectively. The gene discussed is C3; the disease is Decreased total leukocyte count.