Nail‐patella syndrome (NPS), hereditary onycho‐osteodysplasia, is an autosomal dominant disorder of nail dystrophy, patellar absence or hypoplasia, incomplete elbow extension, conical posterior iliac horns, and nephropathy.

We studied the kidneys of an 18‐week spontaneously aborted fetus of a mother with the NPS. Ultrastructural examination of the kidney showed thickening of the capillary walls of the glomeruli and mesangium. There was irregular thickening of basement membranes with subendothelial fibrillar electron‐dense deposits. Immunofluorescence showed fibrinogen deposition in glomerular basement membranes. Fibrinogen deposition in utero may ultimately lead to glomerular fibrosis and intrabasement membrane collagen deposition as seen in the adult renal lesion of this syndrome.

This is the first report of the NPS in which the renal abnormalities have been studied in a fetus. These findings provide support for possible prenatal diagnosis of NPS by intrauterine kidney biopsy. © 1992 Wiley‐Liss, Inc.