What treatment would a patient with variant PKU, where the patient is tetrahydrobiopterin (3H4)-deficient, find helpiul that a patient with classic PKU would not?

a. Limiting phenylalanine intake
b. Introducing active PAH enayme
c. Supplementing tyrosine
d. Supplementing symethe tetraly drobioptein (BFA)
e. More than one is correct