Adenine phosphoribosyltransferase deficiency: Leave no stone unturned

Recurrent DHA nephropathy in renal allograft-revisiting clinicopathological aspects of a rare entity

Background

Adenine phosphoribosyltransferase (APRT) enzyme deficiency is a rare autosomal recessive disorder of purine metabolism affecting mainly the kidneys. It can present at any age with varying degrees of acute and chronic renal damage. Though xanthine dehydrogenase inhibitors offer effective control over the disease process, delay in diagnosis and treatment often lead to compromised function of native and even graft kidneys.

Methods

We have done a retrospective search of records of renal biopsies reported at our center during the 5-year period from 2014 to 2018 to identify biopsies with 2,8-dihydroxyadenine crystal deposits. The demographic, clinical, and histopathological findings in these cases were studied and reviewed in the light of available literature.

Results

Of 9059 renal biopsies received during the study period, 3 cases had the rare 2,8- dihydroxyadenine (DHA) crystals. All of them were diagnosed for the first time on allograft biopsies.

Conclusion

A high index of clinical suspicion together with the characteristic microscopic appearance of crystals on renal biopsy and urine microscopy can clinch the diagnosis of this rare disease. Hence, improving awareness about this entity among clinicians and pathologists is extremely important.

Dihydroxyadenine crystal-induced nephropathy presenting with rapidly progressive renal failure

Adenine phosphoribosyltransferase enzyme deficiency is a rare, autosomal recessive disorder. It is a disease limited to the renal system and usually presents with urolithiasis. Herein, we report a young female with dihydroxyadenine (DHA) crystal-induced nephropathy presenting with rapidly progressive renal failure. DHA crystals can be easily diagnosed by their pathognomic color and shape in urine and biopsy specimens. A high index of clinical suspicion helps in the early diagnosis of this potentially treatable renal disease.