Large amounts of an amino acid were present in the urine. If the condition had been diagnosed at birth, how could the child have been treated to ensure normal development. This question is about one of the best characterized metabolic diseases. Use it to check that you understand the outline of amino acid metabolism, that is, why the body carries out all the various interconversions. The reactions by which phenyalanine is converted to tyrosine are the oxygenase type.
Untreated diabetics are thin because they are breaking down their muscle mass.
There are links in this question with parkinsonism. This Case study is taken from Higgins, S.J., Turner, A.J. and Wood, E.J., Biochemistry for the Medical Sciences. , Longman Scientific and Technical, 1994.