Neonatal pyruvate carboxylase deficiency with renal tubular acidosis and cystinuria

This report concerns a patient with severe congenital lacticacidosis associated with proximal renal tubular acidosis and cystinuria. Enzyme studies with cultured skin fibroblasts obtained from the patient revealed zero pyruvate carboxylase activity, but propionyl-CoA carboxylase activity was normal. Administration of various vitamins in large amounts did not improve the clinical condition. In contrast, the patient began to thrive when her diet was supplemented with aspartic acid, asparagine, glutamic acid, and glutamine. The particular dietary treatment used and the biochemical findings merit consideration for management of future cases.