Incidental findings of rare diseases in organ donors can be seen in allograft biopsies that may have profound implications for the recipient and for the donor and their family. Fabry disease is an X-linked recessive lipid storage disease with cardiovascular, renal and lenticular abnormalities. Phenotypic expression in female heterozygote carriers depends on lyonization. Minimal data exists on outcomes of transplanted kidneys from carriers of Fabry disease. We report a patient with ESRD secondary to focal sclerosis who received a HLA-identical transplant from her sister whose pretransplant donor work up was completely negative. Post-transplant, while pregnant, the recipient developed increasing proteinuria and was biopsied. The biopsy showed extensive myelin figures consistent with Fabry disease. Subsequent genetic, enzymatic and pedigree analysis confirmed the diagnosis in the recipient, the donor and the donor's son. Two years post-transplant the patient continues to have non-nephrotic range proteinuria with normal serum creatinine.