Familial haematuria due to thin basement membrane nephropathy.

Persistent microscopic haematuria, especially when present in young individuals and associated with proteinuria, is generally of glomerular origin. Important causes include glomerulonephritis and Alport's syndrome. A new type of benign familial haematuria has now been reported characterised by little or no proteinuria, no deafness or hypertension and no deterioration of renal function. Examination by electron microscopy of renal biopsy material shows thinning or attenuation of the glomerular basement membrane. A family with thin basement membrane nephropathy is reported to illustrate this newly recognised entity. This disorder should be considered in any patient with persistent microscopic haematuria. Pathologists who assess renal biopsy material should pay greater attention to an ultrastructural morphometric analysis of the glomerular basement membranes of at least two glomeruli.