In Phenylketonuria, the first line therapy is:

In phenylketonuria:- There is accumulation of phenylalanine Accumulated phenylalanine inhibits the transpo of other amino acids required for neurotransmitter synthesis, reduces synthesis and increases degradation of myelin - Mental retardation Breastfeeding introduces phenylalanine and symptoms will be:- 1. Vomiting 2. Irritability 3. Convulsions & tremors are the usual presentations. Thus, limiting the substrate of the deficient enzyme, i.e. phenylalanine, is the first-line of management. Breastfeeding should be avoided.