Membranoproliferative Glomerulonephritis or MPGN is a type of glomerulonephritis caused by immune complexes depositing in the kidney glomerular mesangium and basement membrane (GBM), activating complement and damaging the glomeruli. The GBM is rebuilt ontop of the deposits, causing a "tram-tracking" appearance under the microscope. Glomerulonephritis is a primary or secondary autoimmune renal disease featuring inflammation of the glomeruli. ... The Game Boy Micro Game Boy Micro (GBM) is a micro sized Game Boy Advance set for release by Nintendo in the fall of 2005. ... A complement protein attacking an invader. ...

There are two types of MPGN. The most common by far is Type I, described above. Type II (dense deposit disease) is very similar, except the material deposited is not immune complexes and is not yet known.