[Clinical progress of neonatal non-ketotic hyperglycinemia under treatment].
BACKGROUND
Non-ketotic hyperglycinemia is a congenital error in the breakdown of glycine. The most common type is the classical neonatal form, which begins at the age of a few days with symptoms of lethargy, hypotonia, myoclonia, convulsions, apneas and, frequently, ends in death. Survivors usually develop intractable epilepsy and mental retardation. There is no effective treatment for this condition, but trials have been carried out with a therapy that diminishes the levels of glycine, benzoate (BZ), and another that blocks the excitatory effect in N-methyl-D-aspartate receptors: dextromethorphan (DTM).


METHODS
We report on the progress of a classical neonatal case, which began at the age of a few hours with hypotonia and stupor, without myoclonias or seizures, but with a suppression wave trace on the electroencephalogram (EEG). Cerebrospinal fluid (CSF) showed glycine levels of 141 micromol/L (the normal level is 6.66 +/- 2.66 micromol/L), with a CSF/plasma ratio of 0.19 (the normal ratio is < 0.02). Treatment was started on the thirteenth day with BZ and DTM, and alertness and eye fixation improved in just three days; at the same time the EEG readings become normal. The glycine level in plasma returned to normal at two months and that in CSF was considerably reduced, although with CSF/plasma levels that were still high. At present the patient is 4 years old, has never had convulsions, EEG results have always been normal, and continues with BZ, DTM, carnitine and diet. The patient has presented a high degree of hypermotoric behaviour, but is currently more attentive and more sociable, has been walking from the age of 35 months and has a quotient in the different areas of development of 40-50.


CONCLUSIONS
The clinical progress made by our patient could be said to be anything but negligible, and we therefore recommend that treatment should be started as early as possible after diagnosis.
García-Pérez
A
A
Servicios de Neuropediatría y Neonatología, Fundación Hospital Alcorcón, Alcorcón, Spain. agarcia@fhalcorcon.es
Martínez-Granero
M A
MA
Martín-Ancel
A M
AM
Bonet-Serra
B
B
García-Muñoz
M J
MJ
García-Segura
J M
JM
Viaño
J
J
Lama-More
R A
RA
D001565:Benzoates / Q000627:therapeutic use*; D001921:Brain / Q000033:anatomy & histology; D002331:Carnitine / Q000008:administration & dosage; D002675:Child, Preschool; D003915:Dextromethorphan / Q000627:therapeutic use*; D004035:Diet Therapy; D018691:Excitatory Amino Acid Antagonists / Q000627:therapeutic use*; D005260:Female; D005865:Gestational Age; D005998:Glycine / Q000097:blood / Q000134:cerebrospinal fluid; D006801:Humans; D020158:Hyperglycinemia, Nonketotic / Q000175:diagnosis / Q000188:drug therapy* / Q000473:pathology / Q000503:physiopathology*; D007231:Infant, Newborn; D007234:Infant, Premature / Q000378:metabolism*; D008297:Male; D009043:Motor Activity / Q000502:physiology; D011247:Pregnancy; D016896:Treatment Outcome
D001565:Benzoates; D018691:Excitatory Amino Acid Antagonists; D003915:Dextromethorphan; D002331:Carnitine; D005998:Glycine