HYPERGLYCINEMIA WITH KETOACIDOSIS AND LEUKOPENIA Metabolic Studies on the Nature of the Defect

Metabolic investigations are reported in a patient with the clinical and biochemical features of "idiopathic hyperglycinemia." During ketoacidosis elevated concentrations in serum of numerous amino acids were noted, especially leucine, isoleucine, valine, glycine, and lysine. Hyperammonemia was found in association with ketoacidosis. Clinical and biochemical amelioration was induced by restriction of protein intake to 1 gm/kg or less. Although exacerbation was produced by increasing the protein intake to 1.5 gm/kg, the patient was able to tolerate as much as 3.0 gm/kg of an amino acid mixture in which leucine, isoleucine, valine, methionine, and threonine were absent. It is postulated that this disease, in contrast to hyperglycinemia caused by a specific disorder in glycine metabolism, represents a generalized defect in utilization of amino acids resulting in excessive deamination of certain amino acids in the muscle, with consequent hyperammonemia and ketoacidosis. The nature of the defect in amino acid metabolism is unknown.