A Case Report of a Patient with Pyruvate Carboxylase Deficiency

Abstract

Background: Pyruvate carboxylase catalyzes the carboxylation of pyruvate to oxaloacetate, a crucial intermediate of the tricarboxylic acid (TCA) cycle and the initial step in converting pyruvate to glucose (gluconeogenesis). Pyruvate carboxylase deficiency is a rare metabolic disorder characterized by lactic acidosis, failure to thrive, development delay, and recurrent seizures at an early age in severely affected patients. The onset and severity of pyruvate carboxylase deficiency have been classified as severe neonatal (type B), usually fatal, less severe infantile (type A), compatible with survival but with impaired neurologic development, and milder, later onset (type C) with some residual impairment. Clinical manifestations include hypotonia, mixed hypertonia, ataxia, choreoathetosis, microcephaly, and other signs of impaired white matter development.

Case Report: A 7-day-old baby with a birth weight of 3kg, born to related parents, presented with clinical symptoms such as lethargy, poor feeding, and grunting since birth. Additionally, he experienced a drop in O2 saturation and cyanosis during his hospitalization. Test results revealed lactic acidosis and hyperammonemia. Furthermore, serum amino acids chromatography- HPLC indicated an increase in lysine and citrulline. The patient succumbed after 16 days due to multi-organ damage. Genetic analysis identified pyruvate carboxylase enzyme deficiency.

Conclusion: Pyruvate carboxylase deficiency is a rare inborn error of metabolism that can lead to developmental delay and failure to thrive, typically beginning in the neonatal or early infantile period. The possibility of pyruvate carboxylase deficiency should be considered in any child presenting with lactic acidosis and neurological abnormalities, particularly if associated with hypoglycemia, hyperammonemia, or ketosis.