two pathways: de novo pathway with production of purines from nonpurine precursors, and a salvage pathway in which free purine bases from nucleic acid breakdown from endogenous or exogenous origin are recaptured.
Enzyme hypoxanthine guanine phosphoribosyl transferase (HGPRT) is involved in the salvage pathway.
Deficiency of hypoxanthine guanine phosphoribosyl transferase deficiency leads to increased synthesis of purine nucleotides via the de novo pathway and therefore increases production of uric acid.
Lack of HGPRT seen in X-linked Lesch-Nyhan syndrome.