A PUBLIC HEALTH PERSPECTIVE ON THE IMPORTANCE OF PLASMA PHENYLALANINE AND TYROSINE DETERMINATION IN RELATION TO NEWBORN SCREENING AND MONITORING OF TREATMENT IN PHENYLKETONURIA.

Newborn screening of phenylketonuria (PKU) is performed in many countries, including Romania, in addition to screening for congenital hypothyroidism. Patients affected by PKU require frequent measurements of phenylalanine (Phe) level in blood plasma. Such a determination is important not only in early diagnostic, but also in monitoring the treatment of PKU to maintain phenylalaninemia within limits that will not affect the brain. A simple, highly sensitive, accurate and rather inexpensive procedure for the simultaneous determination of Phe and Tyr plasma concentrations was previously described in this journal. The new procedure may be applied in many clinical laboratories, including those with no previous experience in diagnosis of inherited amino acid metabolic disorders. In this way the major public health problems linked to PKU not being detected in the first weeks of life (including the burden of institutionalized children with preventable mental retardation) may be avoided.