Thin-membrane nephropathy--a common cause of glomerular haematuria.

Thin-membrane nephropathy recently has been described as a cause of glomerular haematuria. The prognosis of the condition is unclear but it generally is considered to be benign. In a series of 92 patients with glomerular haematuria, thin-membrane nephropathy was found to be a common cause, occurring in 26 (28%) patients. Sixteen patients were women. The mean age was 42 years. Four patients had a family history of renal disease or haematuria and no patient was deaf. Haematuria had been present from six days to 30 years. Loin pain occurred in 31% of patients. Hypertension was not a feature and mild renal impairment was present in one case only, while a further three cases showed proteinuria at a level of greater than 500 mg of protein per day. Glomerular basement membranes in patients with thin-membrane nephropathy gave a mean (+/- standard deviation) width of 319 + 37 nm which was significantly (P less than 0.002) less than the control value of 394 +/- 61 nm. On the basis of clinical features and serological parameters, thin-membrane nephropathy could not be separated from other renal causes of haematuria but required careful electronmicroscopic examination of renal biopsy material to establish the diagnosis. Limited follow-up has confirmed the good prognosis of the condition.