Collagenofibrotic glomerulopathy (CG) also known as collagen type 3 glomerulopathy is a rare disease characterized by the deposition of collagen type 3 in the glomeruli. The absence of skeletal abnormalities in these patient is one feature that helps in distinguishing CG from nail patella syndrome, another collagen type 3 deposition disease in renal glomeruli. High serum levels of pro-collagen type III peptide were reported in this disease. Patients may have proteinuria, hematuria and/or renal dysfunction. CG is considered a progressive disease with variable rate of progression. CG manifests as membranoproliferative pattern of injury by light microscopy with negative immunofluorescence. The definitive diagnosis is made by electron microscopy with the characteristic subendothelial and mesangial curved and comma-like banded collagen type 3 fibers of 45-65 nm in periodicity. A retrospective chart review of collagenofibrotic glomerulopathy case at the American University of Beirut Medical Center. A 39 years-old man had a living-related kidney transplant 13 years ago for unknown cause ESKD. An allograft biopsy was performed for rise in creatinine and proteinuria without hematuria. He has been maintained on cyclosporine, azathioprine and prednisone for 12 years before a switch to tacrolimus, mycophenolate mofetil (MMF) and prednisone one year, done prior for a rise in creatinine at an outside hospital. He was diagnosed with hypertension and diabetes mellitus three years prior to biopsy. His family history is negative for renal disease.Table 1Laboratory values at the time of kidney biopsyCreatinine1.8-2.2 mg/dlTacrolimus4.624 hours urine protein1.2 grams24 hours urine albumin0.65 gramsHbA1c7.8 %HIV serologyNegativeHepatitis B and C serologyNegativeUrinalysis+ 2 proteinuria, negative hematuria Open table in a new tab Table 2Pathologic FindingsLight microscopy (LM), figure 1 (H&E x400).Mesangial matrix expansion and hypercellularity, endocapillary hypercellularity, thickened glomerular capillary wall and focal double contour formation.Immunofluorescence (IF)Negative for IgA, IgG, IgM, C3, C4, C1q, kappa and lambda.Electron microscopy (EM) figure 2Accumulation of collagen fibers between the capillary basement membranes and swollen endothelial cells, with increased mesangial matrix deposition. Tubules show tubular injury with cytoplasmic vacuolization. No subepithelial, subendothelial or mesangial electron dense deposits are identified. The capillary loops are patent. Open table in a new tab Figure 2View Large Image Figure ViewerDownload Hi-res image Download (PPT) We are reporting the first case of post-transplant Collagenofibrotic glomerulopathy (CG). The recurrence post-transplant points towards a systemic disease process, including genetic predilection. It highlights the importance of considering unrecognized kidney disease causes in patients with unknown cause ESKD.