This is a little misleading in that the BM is not made of "mesangial cells", but rather there is a thickening of the BM from IC deposits and a splitting of the BM from the proliferation of mesangial cells. Mesangial cells also do not =BM. Splitting hairs here but hey...
Also I think it is misleading to assoc. the C3 and Hep B/C with only the nephrotic presentation as I am sure they can lead to nephritis version of MPGN also. Either way, MPGN can manifest as either syndrome.
Could be that it really doesn't matter as disease prevalence changes. Also when you say Goljan are you referring to rapid review or to the audio? If the audio they are quite a few years (10ish) old.
actually the goljan audio is from 2004 I believe. That makes them 7 not 10ish and I highly doubt the incidence of Type I MPGN has changed appreciably during that time.