Hyperammonemia with citrullinemia.

Two cases of hyperammonemia with elevated citrulline are reported, one resulting from a deficiency of pyruvate carboxylase and the other from a partial deficiency of argininosuccinate synthetase. Diagnosis was based on clinical, biochemical and amino acid profiles. The utility of amino acid determinations in hyperammonemia suspected to underlie an inborn error of metabolism is emphasized.