Congenital nephrotic syndrome is present at birth or appears during the first three months of life and infantile nephrotic syndrome during the first year. Finnish type congenital nephrotic syndrome is an autosomal recessive disease. Nephrotic syndrome is present at birth, severe and does not respond to therapy. Infectious and nutritional complications are frequent. Renal function deteriorates necessitating a dialysis-transplantation program. Between age five and eight. The disease does not recur after transplantation. Diffuse mesangial sclerosis is the second cause of congenital and infantile nephrotic syndrome. It may be isolated or part of a Denys-Drash syndrome (association of the nephropathy with male pseudohermaphroditism and Wilm's tumor). Nephrotic syndrome is resistant to therapy. Renal failure develops in early childhood. Therapy is aimed to prevent oedema, denutrition, infections and thrombosis. Proteinuria does not recur after renal transplantation. Other causes are less frequent.