Inborn Errors of Metabolism in Infancy

he topic of inborn errors of metab-olism is challenging for most phy-sicians. The number of known metabolic disorders is probably as large as the number of presenting symptoms that may indicate metabolic disturbances (Table 11-3). Furthermore, physicians know they may not encounter certain rare inborn errors of metabolism during a lifetime of practice. Nonetheless, with a collective inci-dence of one in 1,500 persons, at least one of these disorders will be encountered by almost all practicing physicians.1-3 Improvements in medical technology and greater knowledge of the human genome are resulting in significant changes in the diagnosis, classification, and treatment of inherited metabolic disorders. Many known inborn errors of metabolism will be recog-nized earlier or treated differently because of these changes. It is important for primary care physicians to recognize the clinical signs of inborn errors of metabolism and to know when to pursue advanced laboratory testing or referral to a children’s subspecialty center