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Currently filtering by tag: APRT

Twitter Poll (February 5, 2020)

Adenine phosphoribosyltransferase (APRT), Twitter Poll, Arkana Laboratories
ANSWER: D 2,8-dihydroxyadeninuria (DHA) disease is a rare autosomal recessive disorder caused by complete adenine phosphoribosyltransferase (APRT) deficiency and manifests as recurrent nephrolithiasis. 2,8-DHA can lead to irreversible renal failure and frequently recurs in the transplants. Adenine phosphoribosyltransferase (APRT) deficiency is a rare autosomal recessive inherited disorder of purine metabolism. APRT catalyzes the formation of adenosine monophosphate from adenine. In the absence of APRT activity, adenine is catabolized by xanthine oxidase to 2,8-dihydroxyadenine (DHA), which is excreted in the urine. DHA is insoluble in the urine at the physiological range of pH, which may lead to crystalluria. The disease is...

2,8 DHA Crystalline Nephropathy

The renal biopsy shown here has crystals present within the tubular lumens and cytoplasm with a brownish appearance by H&E (A) that are strongly silver positive on the Jones methenamine silver stain (B). The crystals are birefringent when viewed under polarized light (C).  These findings are characteristic of 2,8 DHA crystal deposition in the kidney resulting from a deficiency of adenine phosphoribosyltransferase. 2,8 dihydroxyadeninuria is an autosomal recessive disease resulting from pathogenic variants in the APRT gene. It is an important disease to recognize as treatment with a low purine diet and allopurinol therapy blocks formation of 2,8 DHA and...


Adenine phosphoribosyltransferase (APRT) deficiency results from an autosomal recessive enzyme defect of purine metabolism and leads to 2,8-dihydroxyadenine (2,8-DHA) crystalline nephropathy. The clinical presentation of this often misdiagnosed disease is widely variable among patients homozygous for APRT mutations, ranging from asymptomatic in some to reddish-brown diaper stains in infants to recurrent nephrolithiasis, and even CKD in the absence of nephrolithiasis. 2,8-DHA nephropathy has also been reported to recur in the renal allograft resulting in rapid allograft failure. Prompt and accurate diagnosis of this disorder is important so that treatment through pharmacologic inhibition of xanthine dehydrogenase can be initiated. The morphologic findings...