A rare case of dual glomerular pathology: Alport syndrome and immune complex-mediated MPGN.

Background: Immune complex-mediated membranoproliferative glomerulonephritis (IC-MPGN) and Alport syndrome are distinct glomerular diseases with different pathophysiologic mechanisms. Their coexistence is extremely rare and may present diagnostic and therapeutic challenges.

Case presentation: A 42-year-old woman presented with persistent proteinuria and hematuria. Initial laboratory evaluations showed a progressive increase in proteinuria. She had a family history of renal disease. A renal biopsy, which had initially been postponed on patient request, subsequently revealed diffuse mesangial and focal endocapillary proliferation, GBM thickening, periglomerular fibrosis, and immune complex deposition with IgM, C3, and C1q, thereby confirming the diagnosis of IC-MPGN. Genetic testing identified a heterozygous COL4A5 c.1871G > A (p.Gly624Asp) mutation consistent with X-linked Alport syndrome. The patient follows conservative management now.

Conclusion: This case highlights the rare coexistence of IC-MPGN, chronic TIN and Alport syndrome. In patients with progressive glomerular disease, especially with a family history of renal disease or extrarenal findings, genetic evaluation should be considered. Early renal biopsy and genetic testing are essential to guide management in complex cases with overlapping features.