Abnormalities of amino acid metabolism in the newborn

Great advances in the understanding of protein, amino acid and carbohydrate utilization have led the physician to rely heavily on the clinical biochemistry laboratory for monitoring pertinent concentrations which might be altered by a disease state1. One or more biochemical processes may be defective from birth or become defective either temporarily or permanently due to disease later in life. Under these conditions the concentration of normal metabolites may change and in some cases new, abnormal metabolites may appear2,3. Early and accurate recognition of an altered metabolic process is important in any of the inborn errors of metabolism. In many instances a disorder is associated with mental or developmental retardation that may be prevented by early diagnosis and treatment4.