Inborn errors of metabolism of acute onset in infancy.

The detection of more than 70 inborn errors that are brought to medical attention acutely in the neonate and infant relies on the primary clinician's familiarity with the symptoms with which they present. After consideration, appropriate initial screening laboratory tests can be obtained. Certain conditions, such as metabolic acidosis and/or hyperammonemia, with or without hypoglycemia, will signal the need for further consultation with metabolic specialists, as well as for more specific tests. With the information described in this paper, the primary clinician should be able to be the first effective evaluator among many in a process resulting in a precise diagnosis of these inherited conditions. Treatment is available, in both the acute and chronic phases, for many of these disorders. In virtually all of these conditions, for patients in whom the treatment is incomplete or in whom the disorder is lethal, adequate study should make prenatal diagnosis possible. The recurrence risk of at least 1 in 4 makes the recognition of these conditions important. Thoughtful genetic counseling is essential.