The heterogeneous distribution of argininosuccinate synthetase in the liver of type II citrullinemic patients. Its specificity and possible clinical implications.

The authors analyzed the heterogeneous distribution of hepatic argininosuccinate synthetase of type II citrullinemia in reference to its specificity and clinical implications. The low content of the enzyme in the liver of type II citrullinemic patients is associated with two kinds of the enzyme distribution that can be visualized by means of an immunohistochemical method (Saheki and colleagues. Biomed Res 1983;4:235-238). Among the 25 cases of type II citrullinemia examined, 11 exhibited homogeneous distribution of the enzyme, as in the control livers. On the other hand, 14 presented the clustered distribution, in which the hepatocytes stained positively with antisera to argininosuccinate synthetase formed a cluster among the poorly stained cells. No clustered distribution of the enzyme was present in the liver of control patients either with or without liver diseases. No clustered distribution of arginase and aldolase B was observed even in the liver of type II citrillinemic patients. These results suggest that clustered distribution is specific to argininosuccinate synthetase in the liver of type II citrullinemic patients. From considerations concerning the heterogeneous distribution of the enzyme and certain clinical parameters as well, the authors suggest that the clustered type in type II citrullinemia has a less favorable prognosis with regard to fatality.