Pyruvate carboxylase deficiency is a very rare autosomal recessive disorder of metabolism. This disorder is due to a mutation at chromosome 11q13. Pyruvate carboxylase converts pyruvate to oxaloacetate, one of the key substrates of the citric acid cycle. Absence of this substrate significantly impairs cellular energy metabolism.

Patients with pyruvate carboxylase deficiency develop elevated serum lactate and ammonia as newborns or infants. This metabolic acidosis may lead to altered mental status and seizures. Patients go on to show delays in development and growth. Neurologic abnormalities, such as hypotonia, ataxia, and paralysis, also develop. Hypoglycemia is also characteristic of the disease.

Supplementation with biotin (a co-enzyme to pyruvate carboxylase) and thiamine (a stimulator of alternative metabolic pathways) is the primary treatment of pyruvate carboxylase deficiency. Despite treatment-improved metabolic acidosis, neurologic dysfunction remains progressive.