He had negative workup (HIV 1 and HIV antibody and p24 antigen, CMV PCR, EBV PCR, ANA, C3 complement, glomerular basement membrane antibody, hepatitis B PCR, ANCA, fecal parasite concentration, stool culture, stool Wright’s stain test, chest radiograph, total body magnetic resonance imaging) except for anemia (hematocrit 25), plasma cell myeloma (bone marrow biopsy), hyperuricemia, and rapidly progressive glomerulonephritis (systemic hypertension, proteinuria, increased C4 complement to 0.46 g/L). The gene discussed is C4A; the disease is plasma cell myeloma.