A neonate with nonketotic hyperglycinemia who experienced apnea, hiccu
ps and tonic-clonic seizures on the first day of life is reported. The
physical findings and laboratory tests including arterial blood gases
were normal. However, serial blood and CSF aminoacid analyses demonst
rated elevated glycine levels. Serum and CSF glycine levels were 1949
mu mol/L and 415.5 mu mol/L respectively. (Normal serum level is 104-2
54 mu mol/L and CSF level is 5 +/- 2 mu mol/L). The CSF/plasma glycine
ratio was 0.11. Oral sodium benzoate and folic acid therapy was initi
ated. After two weeks of assisted ventilation and clinical improvement
, the patient was discharged with a protein-restricted diet.