Congenital nephrotic syndrome

Abstract

Congenital nephrotic syndrome (CNS) is a rare kidney disorder characterized by heavy proteinuria, hypoproteinemia, and edema starting soon after birth. The majority of cases are caused by genetic defects in the components of the glomerular filtration barrier, especially nephrin and podocin. CNS may also be a part of a more generalized syndrome or caused by a perinatal infection. Immunosuppressive medication is not helpful in the genetic forms of CNS, and kidney transplantation is the only curative therapy. Before the operation, management of these infants largely depends on the magnitude of proteinuria. In severe cases, daily albumin infusions are required to prevent life-threatening edema. The therapy also includes hypercaloric diet, thyroxin and mineral substitution, prevention of thrombotic episodes, and prompt management of infectious complications. The outcome of CNS patients without major extrarenal manifestations is comparable with other patient groups after kidney transplantation.

Fig. 1

Cross-section of a glomerular capillary (left) and electron microscopy image of a normal capillary wall (right). WT1 is a transcription factor important for podocyte function. Nephrin is a major component of the slit diaphragm (SD) connecting podocyte foot processes. Podocin is an adapter protein located intracellularly in the SD area. Laminin is a major structural protein of the glomerular basement membrane (GBM). Genetic mutations in these proteins lead to congenital nephrotic syndrome