Hyperphenylalaninemia is due to defect in the enzyme:: (A) Phenylalanine hydroxylase:, (B) Tyrosinase, (C) Homogentisic acid oxidase, (D) Ornithine transcarbamylase
Answer is A. a. Phenylalanine hydroxylase(Ref: Nelson's 20/e p 636-636)Deficiency of the enzyme phenylalanine hydroxylase or of its cofactor tetrahydrobiopterin (BH4) causes accumulation of phenylalanine in body fluids and in the brain.