HPRT1 and Lesch-Nyhan syndrome: There are many good reviews concerning the housekeeping hypoxanthine phosphoribosyltransferase 1 (HPRT1) gene (MIM: 308000) that encodes the hypoxanthine-guanine phosphoribosyltrnasferase (HGprt) enzyme and the resulting Lesch-Nyhan disease (LND, a rare X-linked recessive neurogenetic disorder) (MIM: 300322); please refer to references [12],[13].