Adenine phosphoribosyl transferase (APRT) deficiency is a rare, autosomal recessive inherited metabolic disorder that generates abundant, poorly soluble 2,8-dihydroxyadenine in urine typically manifesting as recurrent nephrolithiasis, urolithiasis, or crystalline nephropathy, leading to kidney injury and/or kidney failure1,2. Here, APRT is linked to metabolic disease.