Dense intramembranous deposit disease: a clinical comparison of histological subtypes

The accumulation of osmiophilic dense deposits in glomerular mesangial and basement membranes (dense intramembranous deposit disease, or DIDD) is associated with variable histologic alterations of the kidneys. We compared clinical features and long-term renal outcome in 21 patients representing two histologic subtypes of DIDD, namely membranoproliferative glomerulonephritis (MPGN) and focal segmental glomerulonephritis (FSGN). We found that MPGN-type DIDD in 12 patients was associated with nephrotic syndrome in 12, persistent hypocomplementemia in 10 and progression to chronic renal insufficiency in 8. In 9 patients with the focal segmental variety of DIDD, nephrotic syndrome was observed in 3, persistent hypocomplementemia in none, and progression to renal insufficiency in 2 (significance: nephrotic syndrome, p = 0.001; persistent hypocomplementemia, p = 0.0001; chronic renal insufficiency, p = 0.02). In one patient transition from focal segmental to MPGN-type DIDD was observed. We conclude that DIDD is a heterogeneous disorder, and that certain clinical and histologic features may be useful in predicting ultimate outcome.