Citrullinaemia with rapidly fatal neonatal course.

An infant with a deficiency of argininosuccinate synthetase in liver and brain developed rapidly increasing apathy, respiratory insufficiency, and convulsions from the fourth day of life, and died on the seventh day. There was a profound derangement of amino acid concentrations in blood, CSF, and urine, with very high citrulline levels. This patient differs from other cases reported previously, both in her fulminant and fatal course in the neonatal period and in the greater biochemical disturbance.