Carbamyl phosphate synthetase 1 deficiency: A destructive encephalopathy

Carbamyl phosphate synthetase I is a urea cycle enzyme. Severe deficiency o f carbamyl phosphate synthetase I presents in the neonatal period as hypera mmonemic encephalopathy with altered consciousness and occasional seizures after feeding begins. Episodes of altered consciousness with or without sei zures and focal neurologic deficits are seen later with patients of partial carbamyl phosphate synthetase I deficiency. Fatal cerebral edema with brai n herniation may develop on occasion. Three patients presenting with carbam yl phosphate synthetase I deficiency are reported with neuroimaging and pat hologic findings illustrating the destructive encephalopathy with acute cer ebral edema, followed by diffuse cerebral atrophy and occasional cystic enc ephalomalacia. The deterioration in carbamyl phosphate synthetase I deficie ncy occurs during the hyperammonemic crises. This deficiency may be difficu lt to treat despite the current advances in treatment strategies, especiall y in neonatal-onset patients with low carbamyl phosphate synthetase I activ ity. (C) 2001 by Elsevier Science Inc. All rights reserved.