The clinical effects of transient elevation of serum tyrosine level were evaluated in a group of premature infants. Neurologic performance was measured at 15 to 29 months of age using the Bayley Infant Scale of Mental Development. There were no differences in either motor or mental development as measured by this test between infants with high and low serum tyrosine levels.The neonatal course in infants with elevated serum tyrosine levels was compared to that in two groups of infants with low serum tyrosine levels: one group with and one without supplemental ascorbic acid. The only difference in the occurrence of maternal or neonatal complications was in the group with high tyrosine levels, which had significantly greater incidence of symptoms similar to those in infants with neonatal sepsis and characterized by lethargy, poor feeding, and failure to gain weight.A defect in the metabolism of aromatic amino acids in prema¬ ture infants has been recognized for more than 30 years.1 More recent data suggest associated derangements in interrelated neurochemical pathways. Despite the frequent occurrence of this metabolic disturbance, the clini¬ cal significance of this transient ele¬ vation of serum tyrosine level re¬ mains unclear. In view of the critical nature of these neurochemical de¬ rangements, both acute and remote clinical effects of this disorder were evaluated in a group of premature in¬ fants.
Material and Methods