Dense Deposit Disease: MPGN Type II No Longer?

The classical teaching about Dense Deposit Disease (DDD) usually begins with its classification as type II Membranoproliferative Disease.

However, in the most recent edition of the NephSAP "Glomerular, Vascular, and Tubulointerstitial Diseases" module, the case is made that Dense Deposit Disease should no longer be considered as a MPGN.

In a recent review of 69 DDD biopsy specimens, only about 28% of cases demonstrated MPGN histology; the majority (about 50% of cases) actually showed a mesangioproliferative lesion.

In contrast to MPGN Type I (which is often associated with hepatitis C, other chronic infections, or autoimmune disease), DDD is predominantly a pediatric disease that presents as nephritic syndrome. The abnormal irregular GBM deposits appear to arise as a result of unregulated activation of the alternative pathway of complement deposition. Most commonly this results from the presence of C3 nephritic factor (a circulating, activating antibody against C3 convertase) though it can also occur with hereditary factor H Deficiency.