Abstract
We have described a 6-year 7 month-old girl with hyperammonemia due to ornithine transcabamylase (OTC) deficiency accompanied by decreased activity of carbamyl phosphate synthetase (CPS).
Her illness was characterized by reccurent episodes of vomiting and irritability at night since 4 years and 11 months of age. Hyperammonemia, orotic aciduria and high serum glutamine level were observed. The enzyme assays of the biopsied liver tissue revealed that the activities of OTC and CPS wrer markedly deficient (OTC and CPS are 2.5% and 5% of the control values, respectively), but kinetic and physical properties of OTC were normal.
The combined deficiency of OTC and CPS is very rare and this report may be useful for the several problems of OTC deficiency. Treatment with oral amino acids and low protein diet according to protein score and adequate caloric intake has been successful for the control of clinical symptoms and hyperammonemia in this case.
The patient is 7 years old at present and has apparently normal psychomotor development.
The mother showed heterozygous carrier according to the ammonia loading test.
