From the University of Washington and the Puget Sound Blood Center, Seattle, Washington. For current author addresses, see end of text .
Membranous nephropathy is the most common cause of idiopathic nephrotic syndrome in adults.
We describe four patients who developed membranous nephropathy after exposure to toxic concentrations of formaldehyde commonly found in homes with certain types of insulation or cabinetry. Formaldehyde may induce membranous nephropathy in genetically susceptible persons. Methods Four patients with membranous nephropathy were referred to us with possible exposure to toxic concentrations of formaldehyde. Results All four patients presented with the nephrotic syndrome. All had worked with materials that contained formaldehyde or had moved into new homes that had substantial amounts of formaldehyde in the insulation or cabinetry.