Case 2
The patient was the first son of unrelated Dutch parents, born at 41
weeks of gestation. At day 4, he had a remarkable tachypnea and lethargy
that prompted blood gas analysis. The results showed a respiratory
alkalosis (pH 7.6, CO2 2.5 kPa) and elevated ammonia
concentration (270-309 µmol/L). Physical examination revealed no
additional abnormalities. A urea cycle defect was suspected; therefore,
the patient was referred to a metabolic center and treated with sodium
benzoate, an ammonia scavenger medication, dietary protein restriction
and later with NCG. Cerebral ultrasound was normal with no signs of
edema or intracranial bleeding.
Metabolic investigations revealed highly elevated plasma glutamine (1018
µmol/L, normal 208-294) and low-to-normal plasma citrulline whereas the
excretion of orotic acid was normal. This led to the probable diagnosis
of NAGSD. Treatment with protein restriction, citrulline supplementation
and NCG resulted in normal metabolic profile and clinical condition.
The child developed normally except for an impaired vision due to Leber
congenital amaurosis. At present, 7 years old, he attends regular school
with the necessary adaptations because of his blindness. His growth is
unremarkable. His diet is normal and with adequate NCG medication his
amino acid profile is normal.