You are a helpful, respectful, and honest assistant. Always answer as helpfully as possible, while being safe. Your answers should not include any harmful, unethical, racist, sexist, toxic, dangerous, or illegal content. Please ensure that your responses are socially unbiased and positive in nature. If a question does not make any sense or is not factually coherent, explain why instead of answering something not correct. If you don't know the answer to a question, please don't share false information.
What is In Phenylketonuria the main aim of first line therapy is: and explain in detail?
Ans is 'c' i.e. Limiting the substrate for deficient enzyme Classical (typeI) phenylketonuria is caused by deficiency of phenylalanine hydroxylase enzyme. The reaction catalyzed by this enzyme is:Deficiency of phenylalanine hydroxylase results in accumulation of phenylalanine and its byproducts (i.e. Phenyl lactate, phenylacetate and phenylpyruvate). Elevated levels of phenylalanine and its byproducts would lead to severe mental retardation if not treated in infancy.Treatment consists of a special diet low in phenylalanine.(diet must also be supplemented with tyrosine; since tyrosine becomes an essential amino acid due to deficiency of phenylalanine hydroxylase) Initiation of dietary treatment of classic phenylketonuria must occur before the child is 3 weeks of age.