malignant phenylketonuria
what enzyme is absent?
why malignant?
complication?

dihydrobiopterin redactase(catalyze the production of tetrahydrobiopterin(BH4))

refractory to tyrosine supplement
(treatment: BH4 supplementation, low phenylalanine diet)

tryptophan→ ☆↓serotonin
arginine→ ↓nitric oxide

biochemistry UWorld