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Abstract: FR-PO753

Adenine Phosphoribosyl Transferase (APRT) Deficiency as an Underrecognized Cause of Kidney Graft Failure: A Case Report

Session Information

Category: Transplantation

  • 2102 Transplantation: Clinical

Authors

  • Dias Goncalves, Priscila, Mass General Brigham Inc, Boston, Massachusetts, United States
  • Freitas, Geraldo Rubens Ramos, Hospital Universitario de Brasilia, Brasilia, Distrito Federal, Brazil
  • Marques, Brenda Carolina Oliveira, Hospital Universitario de Brasilia, Brasilia, Distrito Federal, Brazil
  • Gatto, Giuseppe Cesare, Hospital Universitario de Brasilia, Brasilia, Distrito Federal, Brazil
  • Arimatea, Gustavo G.Q., Hospital Universitario de Brasilia, Brasilia, Distrito Federal, Brazil
  • Santos, Diego Fernando Figueiredo, Hospital Universitario de Brasilia, Brasilia, Distrito Federal, Brazil
  • Araujo, Stanley A., Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
  • Rennke, Helmut G., Brigham and Women's Hospital, Boston, Massachusetts, United States
Introduction

APRT deficiency is a rare and treatable cause of End-stage Kidney Disease (ESKD) that often goes unrecognized. The recurrence of the disease in the allograft may have dire repercussions. Diagnosis and treatment may prevent graft failure.

Case Description

A 32-year-old male with ESKD previously diagnosed as secondary to chronic interstitial nephritis was referred for a pre-transplant evaluation. Due to a history of kidney stones, he and his family were screened for hyperoxaluria , and the results were negative. He underwent a deceased donor transplant in January 2023 and presented with delayed graft function. A graft biopsy was performed and showed a prominent crystalline nephropathy. The biopsy did not distinguish oxalate from 2,8-dihydroxyadenine (2,8-DHA) crystals. Therefore, a genetic test was ordered, and it was positive for a recessive mutation in the APTR gene. Treatment with allopurinol was started, and kidney function remained stable.

Discussion


APRT is the enzyme responsible for adenosine metabolism.APRT deficiency leads to the conversion of adenine into 2,8-DHA by xanthine dehydrogenase. This insoluble compound precipitates in the urine, resulting in the formation of kidney stones and crystal nephropathy. Diagnosis is often challenging and usually made after allograft failure. Genetic testing should be widely available as Allopurinol is an effective treatment.