SEARCH Articles Figures Tables 2-Amino-4-hydroxy-6-methyl-5, 6-dihydropteridine 2.4- Diamino-7,8-dihydropteridines 4- Hydroxy-3,4-dihydropteridine Dihydropteridine reductase Dihydropteridine reductase deficiency Dihydropteridine reductase deficiency DHPR) Phenylketonuria Dihydropteridine