Nutrition therapies for inborn errors of metabolism

Inborn errors of metabolism are rare, but important causes of disease in the neonate. They cause significant morbidity and mortality that can in some cases be ameliorated or prevented by nutritional treatment. An increasingly large numberof inbornerrors of metabolism are being described many of which present or can be identified in the newborn period. Premature infants have no less risk of inborn errors of metabolism than full-term neonates. However, inborn errors may be less frequently suspected in the premature infant because symptoms may resemble more common problems expected in those patients. In addition, diagnostic tests in the premature infant may be altered by common treatments. For example, whole blood transfusions can give false negative results on newborn screening for galactosemia. Premature infants are actually at higher risk for transient formsofsomeinbornerrors forwhichacritical enzyme shows maturation in the perinatal period. In addition, advances in technology have led to the description of an increasing number of inborn errors of metabolism. For each disorder, identification of specific abnormal metabolites leads to understanding the unique biochemistry of the disorderandis the key to developingapproaches to management. Nutrition plays an important role in the management of inborn errors of metabolism. The benefit of a phenylalanine-restricted diet for PKU was described by Bickel and associates in 1953 after it was shown that modification of dietary intake could alter the biochemical imbalances of the patient.