Light Chain Podocytopathy Mimicking Recurrent Focal Segmental Glomerulosclerosis.

Area of Science:

• Nephrology
• Hematology
• Immunology

Background:

• Paraproteinemia commonly causes kidney injury in adults over 40, linked to plasma cell dyscrasias.
• Kidney transplantation for paraprotein-related kidney disease requires treating the underlying hematologic disorder to prevent recurrence.
• Recurrent kidney injury post-transplantation is frequent if the hematologic response is inadequate.

Observation:

• A 23-year-old male presented with end-stage kidney disease, initially diagnosed as focal segmental glomerulosclerosis.
• The patient underwent two kidney transplantations, experiencing recurrent proteinuria in both allografts.
• Retrospective review revealed kappa-restricted crystalline light chain podocytopathy in native and allograft kidneys.

Findings:

• Recurrent light chain podocytopathy was identified in a young patient, a presentation not previously reported.
• The condition mimicked focal segmental glomerulosclerosis, posing a diagnostic challenge in younger individuals.
• Paraprotein-related kidney injury is typically not suspected in young patients.

Implications:

• This case expands the known spectrum of light chain podocytopathy to include recurrent forms in young transplant recipients.
• Early recognition and diagnosis of light chain podocytopathy are crucial, especially in young patients with kidney disease.
• Consideration of paraproteinemia is important in young patients with apparent focal segmental glomerulosclerosis and kidney allograft dysfunction.