IN THE NEWS- DENSE DEPOSIT DISEASE AND MGUS?

The connection of Dense Deposit Disease and MGUS is unique and recently investigators explored this in a series of patients at the Mayo Clinic.
All 10 patients had a serum monoclonal spike of IgG k or lambda and then had a biopsy proven dense deposit disease.
A presumptive pathophysiology is mentioned: Perhaps the MGUS leads to activation of formation of Antibodies of Factor H or regulators of complement activators.  This can be compounded by H402 Allele of Factor H that is making it second hit for DDD.  This leads to dysregulated complement activation and a full blown C3 glomerulopathy and dense deposit disease.
Most of these 10 patients either had a low alternative pathway , autoantibody to factor H or heterozygosity to H402 allele of Factor H.  MGUS is associated with this phenomenon or just another bystander and nothing to do with DDD, is not clear.  4 of their 10 patients became ESRD, 2 are CKD and remaining are a recent diagnosis. So its unclear if this DDD is behaving like the classic DDD with quick progression to ESRD.

Interesting observation and something to keep in mind.
Image source: Imperial College, London, UK
References:

http://www.ncbi.nlm.nih.gov/pubmed/20832153
http://www.ncbi.nlm.nih.gov/pubmed/20185597
http://www.ncbi.nlm.nih.gov/pubmed/20852386