In the neonatal type of this disorder symptoms resemble those of classical ornithine transcarbamylase deficiency or carbamoyl phosphate synthetase deficiency . There is poor feeding, lethargy and irritability within the first few days, followed by drowsiness, coma and death if no treatment is given. With treatment prognosis remains poor. Citrulline is grossly elevated in plasma and urine. A subacute type presents during the first year with convulsions, ataxia and failure to thrive, and in a further variant there is onset in childhood or adulthood with a longer course.
Enzyme Tests: [14C]-citrulline incorporation in cultured fibroblasts is measured to diagnose this disorder.