HPRT1 (Hypoxanthine Phosphoribosyltransferase 1): HPRT1 is a crucial gene involved in purine metabolism. It catalyzes the conversion of hypoxanthine into inosine monophosphate (IMP), a key precursor for purine nucleotide synthesis. Mutations in HPRT1 can lead to Lesch-Nyhan syndrome, a rare genetic disorder characterized by neurological and behavioral abnormalities.