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Currently filtering by tag: Dihydroxyadenuria

Diagnose This! (October 16, 2017)

What is your diagnosis?       The photomicrograph shows a distended tubule with an intratubular crystalline cast with argyrophilia. While crystalline casts can be seen from calcium phosphate, calcium oxalate and others, the presence of argyrophilia on silver stain is characteristic for 2,8-Dihydroxyadenuria (DHA) crystals. 2,8-DHA is a rare, autosomal recessive trait caused by a genetic deficiency in adenine phosphoribosyltransferase (APRT). Accurate diagnosis is critical (especially in those with limited chronicity) as treatment exists that can ameliorate renal damage in some patients. And, in patients with the undiagnosed disease who undergo a transplant, the disease will reoccur unless pharmacologic...


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...