DDD would be described as “membranoproliferative glomerulonephritis (MPGN, sometimes also called mesangiocapillary glomerulonephritis) type II,” or “MPGN type I with isolated C3 deposits.” However it has been known for some time that most DDD cases show a different (inflammatory) glomerular pattern than MPGN.6 The gene discussed is C3; the disease is primary membranoproliferative glomerulonephritis.