Laboratory results demonstrated autoimmune hemolytic anaemia, C3 positivity, elevated immunoglobulin (Ig)G, elevated lactate dehydrogenase (LDH), low haptoglobin, elevated reticulocyte count, elevated RDW-CV (red blood cell distribution width-corpuscular volume), positive direct Coombs test, thrombocytopenia, and proteinuria, all of which led to an underlying ES. The gene discussed is C3; the disease is autoimmune hemolytic anemia.