Clq nephropathy presenting as rapidly progressive crescentic glomerulonephritis

C1q nephropathy is an immune complex glomerulonephritis defined by the pres ence of mesangial immunoglobulins and complement deposits, most notably C1q , and the absence of clinical and laboratory evidence of systemic lupus ery thematosus. Histology in C1q nephropathy is characterized by a slight to se vere increase in mesangial cellularity and matrix, with or without segmenta l sclerosis. C1q nephropathy usually presents with nephrotic-range proteinu ria in older children and young adults, and has a poor response to steroids . Patients may have decreased creatinine clearance at presentation, but pro gression to end-stage renal disease (ESRD) is slow. Seven crescentic glomer ulonephritis has not been reported in C1q nephropathy. We describe a 3-year -old Hispanic girl who presented with renal insufficiency. Kidney biopsy sh owed C1q nephropathy with severe crescentic glomerulonephritis. The clinica l and serological evaluation ruled out systemic lupus erythematosus or othe r immunological or infectious etiologies. In spite of immunosuppressive the rapy, she progressed to ESRD within 14 weeks and is currently on chronic pe ritoneal dialysis. The atypical features of C1q nephropathy observed in our patient, which have not been described in earlier reports, are an early ag e of onset, severe crescentic glomerulonephritis, and rapid progression to ESRD. C1q nephropathy should be added to the differential diagnosis of glom erulonephritis in young children and in the patient with crescentic glomeru lonephritis.