The laboratory results included leukopenia (3 points), thrombocytopenia (4 points), proteinuria > 0.5 g/24 h (4 points), low C3 and C4 levels (4 points), and the presence of anti-dsDNA antibodies (6 points), resulting in a total score of 18 points (per EULAR/ACR guidelines, only the highest-weighted item within a domain is counted (here, thrombocytopenia [4 points] > leukopenia [3 points]). The gene discussed is C3; the disease is Decreased total leukocyte count.