We report on 10 children, less than 2 years of age, who presented with a genuine type of glomerulopathy: diffuse mesangial sclerosis. In 5, the nephropathy was associated with male pseudohermaphroditism (MPH) and Wilms' tumor (WT); in 3 with MPH and in 2 with WT. The nephropathy was characterized by its very early onset, between the age of 2 weeks and 18 months. Eight patients presented with a nephrotic syndrome with (7 cases) or without (1 case) hypertension. All, but one, who is in advanced RF at 11 years of age, progressed to chronic or end-stage renal failure (ESRF) within a few months to 2 years from the onset. One additional child presented with advanced renal failure at the age of 8 months and the last one, who was hypertensive, developed an anuria related to thrombosis of renal veins at 1 year of age. Drash syndrome is characterized by the association of a "nephron disorder" with MPH and WT. We propose, on the basis of our histological findings, to extend the concept of Drash syndrome to patients who, in addition to the nephropathy, have either WT or MPH and to consider the distinctive glomerular lesions presented by all these patients as their common denominator. The pathogenesis of this glomerulopathy is obscure. Its early onset, its association with a dysembryoplastic tumor and/or with gonadal dysgenesis both suggest an antenatal dysgenetic process.