Acquired cystinuria in a kidney transplant recipient

Cystinuria is a rare autosomal recessive hereditary disorder characterized by increased urine cystine excretion and recurrent kidney stone formation. Acquired cystinuria after kidney transplantation is extremely rare, with, to our knowledge, a single case described in the literature, albeit without genetic explorations. We herein report a 59-year-old male kidney transplant recipient, without history of urolithiasis, who developed cystine stones in the allograft. Genetic studies revealed a homozygous pathogenic mutation in the <i>SLC3A1</i> gene in the deceased donor. This case demonstrates the potential for transmission of cystinuria through the kidney allograft and underlines the value of genetic analysis in the donor.