A newborn presents at birth with massive generalized edema, enlarged placenta reported by the obstetrician, and severe proteinuria. Both parents are consanguineous. Renal biopsy later shows microcystic dilatation of proximal tubules. The defect lies in a slit diaphragm structural protein. The affected gene encodes:

• A Nephrin ✓
• B Podocin
• C Alpha-actinin-4
• D TRPC6 channel

Explanation

Congenital nephrotic syndrome of the Finnish type results from autosomal recessive NPHS1 mutations encoding nephrin, the key transmembrane component of the slit diaphragm. It manifests in utero with heavy fetal proteinuria, placentomegaly and prematurity. NPHS2 (podocin) mutations cause steroid-resistant nephrotic syndrome of early childhood rather than the congenital Finnish form, while ACTN4 and TRPC6 cause autosomal dominant adult-onset FSGS.

Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.