Experience with early treatment using febuxostat in a patient with adenine phosphoribosyltransferase deficiency after pediatric kidney transplantation: a case report.

Kidney transplantation (KT) for adenine phosphoribosyltransferase (APRT) deficiency is performed using the xanthine dehydrogenase (XDH) inhibitor allopurinol to prevent the recurrence of dihydroxyadenine (DHA) nephropathy. However, there are few reports on the use of febuxostat after pediatric KT for APRT deficiency. Herein, we report the case of a 12-year-old boy with congenital kidney and urinary tract abnormalities who underwent deceased-donor KT for end-stage kidney disease caused by APRT deficiency. The patient developed acute kidney injury during infancy due to urinary tract stones and was diagnosed with APRT deficiency based on stone analysis and genetic testing. Treatment with allopurinol was initiated. However, the patient had persistent renal dysfunction and required peritoneal dialysis at the age of 9 years. Grade IV left vesicoureteral reflux (VUR) and a large bladder diverticulum were observed. Although the VUR resolved, the patient underwent bladder diverticulectomy and ureteroneocystostomy before KT due to recurrent complicated urinary tract infections associated with an enlarged bladder diverticulum and residual urine. Subsequently, the patient underwent KT, and the XDH inhibitor was switched from allopurinol to febuxostat. Transplant renal biopsy at 4 months post-KT showed no recurrence of DHA nephropathy; graft function remained stable. This case demonstrated that pediatric patients with APRT deficiency undergoing KT could be successfully managed with febuxostat.