Phenylalanemia I is due to deficiency of ?: (A) Phenylalanine hydroxylase, (B) Homogentisate oxidase, (C) Tyrosinase, (D) None
Answer is A. Phenylalanine hydroxylase i) Classical phenylketonuria (hyperphenylalanemia type I) Deficiency of phenylalanine hydroxylase.ii) Atypical phenylketonuria (hyperphenylalanemia type II and III) * Defect in dihydrobiopterin reductase.iii) Hyperphenylalanemia type IV and V * Defect in dihydrobiopterin synthesis.