An autosomal recessive metabolic disorder caused by absent or decreased pyruvate carboxylase activity, the enzyme that regulates gluconeogenesis, lipogenesis, and neurotransmitter synthesis. Clinical manifestations include lactic acidosis, seizures, respiratory distress, marked psychomotor delay, periodic hypoglycemia, and hypotonia. The clinical course may be similar to leigh disease. (From Am J Hum Genet 1998 Jun;62(6):1312-9)