The effect of short-term dimethylglycine treatment on oxygen consumption in cytochrome oxidase deficiency: a double-blind randomized crossover clinical trial.
OBJECTIVE
To study the effectiveness of dimethylglycine (DMG) on oxygen consumption (VO(2)) in children with Saguenay-Lac-Saint-Jean cytochrome-c oxidase (SLSJ-COX) deficiency (OMIM 220111).


METHODS
In a crossover randomized double-blind clinical trial, 5 children with SLSJ-COX deficiency, who were stable and old enough to comply with VO(2) measurement, were treated with placebo or DMG for 3 days, and with the alternate treatment after a 2-week washout period. VO(2) was measured by indirect calorimetry before and after treatment. Dietary caloric intake was calculated for 3 days before each measurement. Mean caloric intakes per day were 1562 and 1342 kcal x m(-2) before and during placebo, 1,336 and 1,380 before and during DMG, respectively.


RESULTS
DMG was well tolerated and, in all cases, resulted in markedly increased blood DMG levels (617 + 203 mmol x L(-1)), versus 0 to 2 mmol x L(-1) without treatment. Mean VO(2) was lower after administration of either DMG (-1 +/- 3 mL x min(-1) x m(-2)) or placebo (-6 +/- 4), but neither difference was statistically significant. There was no detectable effect of DMG treatment on blood levels of lactate, pyruvate, bicarbonate, or pH. VO(2) values of patients (range, 101-135 mL x min(-1) x m(-2)) were lower than published norms (150-160 mL x min(-1) x m(-2)).


CONCLUSIONS
This study suggests that treatment with DMG does not substantially change VO(2) in children with SLSJ-COX deficiency.
Liet
Jean-Michel
JM
Department of Pediatrics, Sainte-Justine Hospital, Montreal, Canada.
Pelletier
Véronique
V
Robinson
Brian H
BH
Laryea
Maurice D
MD
Wendel
Udo
U
Morneau
Sylvain
S
Morin
Charles
C
Mitchell
Grant
G
Lacroix
Jacques
J
D002648:Child; D002675:Child, Preschool; D018592:Cross-Over Studies; D030401:Cytochrome-c Oxidase Deficiency / Q000188:drug therapy* / Q000378:metabolism*; D004311:Double-Blind Method; D004334:Drug Administration Schedule; D005260:Female; D006801:Humans; D008297:Male; D010101:Oxygen Consumption / Q000187:drug effects*; D012521:Sarcosine / Q000008:administration & dosage* / Q000031:analogs & derivatives*; D016896:Treatment Outcome
C025138:dimethylglycine; D012521:Sarcosine