Update on inborn errors of metabolism: primary lactic acidemia.

Initially thought to be rare, primary lactic acidemia is diagnosed with increasing frequency. Elevations in lactate and pyruvate are markers for a variety of metabolic blocks. Although there have been great strides made in the diagnosis and treatment of lactic acidemia, much remains to be learned. As laboratory techniques improve, clinicians will be able to make an exact enzymatic diagnosis on an increasing percentage of patients. Specific enzymatic diagnosis also will help clinicians determine inheritance patterns, recurrence risks, and methods of prenatal diagnosis.