2,8-dihyroxyadenine (DHA) crystalline nephropathy: A case report

Adenine phosphoribosyltransferase (APRT) deficiency is a rare autosomal disorder with extremely variable presentation. The disease spectrum ranges from completely asymptomatic to 2,8-dihydroxyadenine (DHA) stones to massive deposition of DHA crystals leading to DHA crystalline nephropathy. We report a case of a 45-year-old woman who presented with acute kidney injury and recurrent vomiting. Kidney biopsy revealed precipitation of brown crystals in tubular lumina with acute tubular injury with characteristic birefringence on polarizing light, confirming the unexpected diagnosis of DHA crystalline nephropathy. She was started on a xanthine oxidase inhibitor which resulted in an improvement of kidney function. This case highlights the fact that APRT deficiency can have varied presentations and is an important hereditary cause of crystalline nephropathy.