Neonatal type of argininosuccinate synthetase deficiency. Report of two cases with autopsy findings.

Two autopsy cases of neonatal argininosuccinate synthetase (ASS) deficiency demonstrating the particular histological changes of the liver are presented. Case 1 was a female infant with elevated blood ammonia and citrulline. The patient died of sepsis at nineteen days after birth. Autopsy revealed hematomas in bilateral cerebral hemispheres and a yellow liver parenchyma. Histologically, the cerebrum showed diffuse astrogliosis with Alzheimer type II cell and swollen cytoplasm. Status spongiosus and gliosis were observed in the subthalamic and pontine nuclei. The liver demonstrated fatty degeneration and wide portal space with bile duct proliferation and inflammatory cell infiltration. The ASS activities in the liver and the kidneys were not detected. Case 2 was a female infant who died of respiratory distress twenty-four days after birth. Autopsy revealed hematomas in the bilateral cerebral ventricles and a liver with yellow parenchyma. Histologically, there was destruction of arrangement in the cerebrum and cerebellum together with marked decrease of nerve cells with gliosis and phagocytosis. The liver showed mild fatty degeneration and wide portal space accompanied by bile duct proliferation and inflammatory cell infiltration. The ASS activities in the liver and kidneys were not detected.