A case of persistent low C3 serum level with MPGN pattern: five-year follow up

Abstract

A 10-year-old girl visited for microscopic hematuria and proteinuria on school urine screening. She was asymptomatic with normal renal function. Persistent C3 hypocomplementemia led her to a kidney biopsy. First biopsy showed membranoproliferative glomerulonephritis (MPGN) pattern with only C3 deposition on IF and mesangial electron dense deposits. She was under supportive therapy including angiotensin-converting enzyme (ACE) inhibitor for over two years. During the period, she did not have renal symptoms nor proteinuria. But microscopic hematuria and C3 hypocomplementemia had persisted. After 33 months of treatment, the patient quit medication on her own. Over one year later, she revisited clinic with microscopic hematuria and normal renal function at the age of 15. She denied of any symptoms during the entire period. Kidney function was within normal range, without decline, and C3 hypocomplementemia persisted. A second kidney biopsy was taken for nephrotic-range proteinuria (53.37 mg/m2/hr). Points of interest: (1) Morphologic progression of this GN after five years with only supportive therapy, (2) pathogenesis and treatment strategies, so far.