Clinical and morphological features of collagen type III glomerulopathy: a report of nine cases from a single institution

Aims: We report nine Chinese patients with collagen type III glomerulopathy. Methods and results: Two males and seven females were studied, ranging in age from 21 to 67 years. Proteinuria and hypertension were the most common symptoms, with incidences of 88.9 and 77.8%, respectively. Two patients had abnormal renal function. Their histological appearances varied. Massive eosinophilic and weakly periodic acid-Schiff (PAS)-positive substances were deposited along the capillary loops and in the mesangial area in three cases, while others had thickened capillary walls with a chain-like structure or double-contour appearance of the PAS- and silver-stained sections. Immunofluorescence analysis showed the abundant deposition of collagen type III. Electron microscopy revealed massive scattered or bundle-shaped fibre-like materials in the subendothelial and mesangial areas. During follow-up, 44.4% of the patients suffered a doubling of serum creatinine. The level of serum creatinine at biopsy was an independent predictor of this doubled serum creatinine value. Conclusions: Collagen type III deposits in the subendothelial and mesangial areas. Some patients show global nodular lesions, while others show subtle changes only via PAS/silver staining. Proteinuria and hypertension are the most common symptoms, and the serum creatinine level at biopsy is an independent predictor of the doubling of serum creatinine during follow-up.