10 Neonatal screening for inborn errors of amino acid metabolism

Abstract

Neonatal screening for the inborn errors of amino acid metabolism andtransport, begun as only phenylketonuria (PKU) screening, is gradually becoming more widespread and encompassing many different disorders. The basic screening methods used are the. ‘Guthrie’ tests and, in some instances, paper chromatography. PKU still ranks as the most important disorder sought, in terms of frequency and effectiveness of treatment. However;, other disorders, such as maple syrup urine disease and homocystinuria, are also important. Neonatal screening, in addition to identifying affected infants for the purpose of therapy, will also result in a vast amount of new information of immeasurable importance to our understanding of the role of these disorders in clinical disease. However, before therapy can be instituted or accurate information gained, it is imperative that proper diagnosis be made by the use of repeat testing and confirmatory procedures. Artifacts and transient findings often mimic the findings in a true genetic disorder. Screening programs for such genetic disorders will continue to grow and become more comprehensive. It is important that regionalisation of testing should begin so that large and experienced central laboratories and centres can serve as the primary facilities. Only in this manner will neonatal screening be both effective and efficient.