Normally in humans, adenine formed in processes such as polyamine biosynthesis can be salvaged by conversion to AMP, catalyzed by APRT (adenine phosphoribosyltransferase). In the absence of APRT activity, however, accumulated adenine is instead converted to 2,8-dioxo-adenine. Accumulation of insoluble crystals of 2,8-dioxo-adenine in the kidneys causes the kidney damage that is a major symptom of APRT deficiency in humans (Van Acker et al. 1977; Bollée et al. 2012).
Defects in APRT and HGPRT lead to synthesis of 2,8-dioxo-adenine and overproduction of uric acid, respectively, associated with kidney damage and other symptoms (Bollée et al. 2012; Fu & Jinnah 2012). Defects in ADA lead to accumulation of (deoxy)adenosine and consequent severe combined immunodeficiency (Akeson et al. 1988).
Cytosolic APRT dimer catalyzes the reaction of adenine and 5-phospho-alpha-D-ribose 1-diphosphate to form AMP and pyrophosphate (Holden et al. 1979; Silva et al. 2008).
Normally in humans, adenine generated in processes such as polyamine biosynthesisis can be salvaged by conversion to AMP, catalyzed by APRT (adenine phosphoribosyltransferase). In the absence of APRT activity, however, accumulated adenine is instead converted to 2,8-dioxo-adenine. Accumulation of insoluble crystals of 2,8-dioxo-adenine in the kidneys causes the kidney damage that is a major symptom of APRT deficiency in humans (Van Acker et al. 1977; Bollée et al. 2012). Three missense mutant alleles are annotated here (Chen et al. 1991; Hidaka et al. 1988; Sahota et al. 1994); nonsense, insertion-deletion, and splice-site mutations have also been reported (reviewed by Bollée et al. 2012).