A clinicopathological study of C1q nephropathy

We studied the clinicopathological findings of the patients with C1q nephropathy. Among a total of 277 series of first renal biopsies, seven cases met the diagnostic criteria of C1q nephropathy. In five cases, renal biopsies were performed because of asymptomatic urine abnormalities. The age of onset ranged from 5 to 13 years (8.7 years on average). All cases showed histologic features of mesangial proliferative glomerulonephritis. On electron microscopy, five cases showed electron-dense deposits in the capillary loop as well as in the mesangial area. Treatment with corticosteroid was performed in three cases. After the follow-up period of 4 to 17 years (8.0 years on average), one patient showed microscopic hematuria, and other patients showed normal urinary findings. Our data indicate that most of C1q nephropathy cases are found with asymptomatic urine abnormalities detected by school urinary screening program, and that these cases may have a better clinical course.