Lesch Nyhan syndrome (DYT/CHOR-HPRT) is an inborn disorder caused by a deficiency of the hypoxanthine-guanine phosphoribosyltransferase (HPRT) enzyme, involved in the purine salvage pathway whose inactivation causes an increase in guanine and hypoxanthine, which eventually gets converted into uric acid [120]. Here, HPRT1 is linked to Lesch-Nyhan syndrome.