2,8 Dihydroxyadeninuria — A Renal Biopsy Case Series
Larry N Cossey, Eze Chukwuma, Samih Nasr, Christopher P Larsen. University of Arkansas for Medical Sciences, Little Rock, AR; Nephrology Associates of Dayton, Dayton, OH; Mayo Clinic, Rochester, MN; Nephropath, Little Rock, AR
Background: 2,8 dihydroxyadeninuria (DHA) is a rare autosomal recessive disorder caused by a deficiency of adenine phosphoribosyltransferase (APRT) which is frequently misdiagnosed on renal biopsy. It can be treated pharmacologically but causes irreversible renal injury and progression to ESRD if left untreated. This study reports three patients with DHA crystalline nephropathy diagnosed via percutaneous renal biopsy.
Design: In this retrospective review, three cases of DHA crystalline nephropathy were identified. Pathologic description and pertinent clinical data is provided.
Results: Two patients were female, one male; two African American and one Caucasian. Past medical history included hypertension in 2/3 and obesity in 1/3. One patient had a maternal history of CKD. Patients had no history of nephrolithiasis or obstruction. Creatinine levels at presentation ranged from 2.01-10.3 (mean of 5.2). Proteinuria was identified in two patients (550 mg/d and 2 gm/d). Renal biopsies showed a range of 5-42 glomeruli with 7-22% globally sclerotic. Needle-shaped, birefringent brownish yellow crystals were identified in all cases within tubular lumina, tubular epithelial cell cytoplasm, and interstitium, and were positive on silver stain in all cases. Tubular atrophy and interstitial fibrosis was severe in all cases. There was a focal multinucleated giant cell reaction to the crystals in all cases. APRT RBC activity was mildly decreased in one patient, markedly decreased in another, and is unknown in one patient. Two patients have progressed to ESRD, one of whom received a kidney transplant with disease recurrence 4 months post-transplant. The third patient has been lost to follow-up.
Conclusions: DHA is a rare cause of renal disease that can lead to irreversible renal failure. Clinically, there are no distinguishing characteristics of DHA and awareness of this disease among clinicians is low. Morphologically, DHA crystals can be confused with oxalate crystals but can be differentiated by special staining methods. It is important that pathologists be aware of DHA in the differential diagnosis of crystalline nephropathy as it has a poor prognosis and frequently recurs in transplants.
Category: Kidney (does not include tumors)
Wednesday, March 21, 2012 1:00 PM
Poster Session VI # 300, Wednesday Afternoon