Abstract: TH-PO590
APRT Deficiency Related Crystalline Nephropathy Causing Acute Renal Allograft Dysfunction: A Case Report
Session Information
- Trainee Case Reports - II
October 25, 2018 | Location: Exhibit Hall, San Diego Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Trainee Case Reports
- 1002 Genetic Diseases of the Kidney: Non-Cystic
Authors
- Patil, Sudip Madhukar, Max Super Speciality Hospital, New Delhi, Delhi, India
- Gupta, Sagar, Max Super Speciality Hospital, New Delhi, Delhi, India
- Khullar, Dinesh, Max Super Speciality Hospital, New Delhi, Delhi, India
Introduction
APRT(Adenine Phosphoribosyl Transferase) deficiency is an AR metabolic disorder that leads to accumulation of insoluble purine dihydroxyadenine (DHA) in the kidney. It results in crystalluria & urinary stones leading to renal colic,hematuria,UTI & renal failure.Age at presentation can range from 5 months to late adulthood. Upto 50% of patients may be asymptomatic.Prevalence is largely unknown.Lack of awareness, inadequate evaluation of stones & confusion of DHA crystals with uric acid or calcium oxalate contribute to diagnosis being missed. We report here a case of acute renal allograft dysfunction secondary to APRT deficiency related crystalline nephropathy, a relatively rare entity.
Case Description
A 51 year-old male was evaluated for acute allograft dysfunction. His past history was significant for ESRD secondary to nephrolithiasis. No stone biochemical analysis or genetic studies were performed.He underwent living unrelated kidney transplantation (donor wife) 3 months back.Post-operative period was uneventful with nadir S.Crt of 1.2mg/dl.Basiliximab for induction and tacrolimus,MMF& prednisolone were used for maintenance immunosuppression.On routine labs he was found to have S.Crt of 2.3mg/dL. USG allograft was unremarkable. Renal allograft biopsy was performed and showed 0/5 glomeruli being sclerosed. Tubulopathic changes in form of tubular epithelial simplification and intraluminal polarizable crystals were noted. No evidence of rejection was found. A histopathological diagnosis of acute tubular injury with tubular crystallization was made.24hUr oxalate level was 55.6mg/d(N<45) & Pl.Oxalate was 3.34µmol/L(N< 3.0).Genetic analysis revealed a previously unreported homozygous nonsense mutation in exon 3 of APRT gene.Hence a clinical diagnosis of APRT deficiency related renal disease was made.He was started on Allopurinol 100mgBID with low purine diet & increased fluid intake.S.Crt gradually improved to 1.2 and has remained stable for last 1 year.
Discussion
Initial presentation of APRT deficiency can be insidious onset of renal dysfunction due to crystalline tubulopathy or interstitial nephritis without urolithiasis. High index of suspicion, correct identification of DHA crystals, renal biopsy & genetic testing are needed to clinch the diagnosis. Treatment with allopurinol, low purine diet and increased fluid intake is simple & effective.