Kidney biopsy of congenital nephrotic syndrome of the Finnish type

Kidney biopsy from an infant with congenital nephrotic syndrome of the Finnish type due to mutations in the NPHS1 gene that encodes nephrin, a transmembrane protein located at the slit diaphragm of the glomerular podocytes. Histologic changes include the characteristic findings of mild mesangial hypercellularity and increased mesangial matrix in the glomeruli, as well as irregular microcystic dilatation of proximal tubules.