APRTase is an enzyme involved in the purine nucleotide salvage pathway. It functions as a catalyst in the reaction between adenine and phosphoribosyl pyrophosphate (PRPP) to form AMP. APRTase is labeled as EC 2.4.2.7. APRT is functionally related to hypoxanthine-guanine phosphoribosyltransferase (HPRT).Deficiency of APRT in human beings may lead to kidney stones formed of adenine and salts.2,8 dihydroxy-adenine urolithiasis is also known as "adenine phosphoribosyltransferase deficiency".

Defects in APRT are the cause of APRT deficiency; also known as 2,8-dihydroxyadenine urolithiasis. It is an autosomal recessive disease characterized by renal failure. Patients have 2,8-dihydroxyadenine (DHA) urinary stones.