Methylmalonic acid values in healthy Dutch children.
BACKGROUND
Plasma methylmalonic acid (MMA) is a specific marker for functional cobalamin deficiency. This deficiency can give rise to non-specific but serious symptoms in childhood such as developmental delay, convulsions and failure to thrive and may even lead to irreversible neurological damage.


OBJECTIVE
To analyse plasma MMA concentrations in Dutch children and to evaluate possible factors influencing its concentration.


METHODS
A number of 186 Dutch children aged 0-19 years were analysed cross-sectionally. Blood was collected to measure MMA, total homocysteine (tHcy), cobalamin (Cbl) and serum creatinine concentrations. In addition, information about medical history, age and sex was recorded.


RESULTS
The geometric mean (GM) plasma MMA concentration was 0.17 micromol/l (95% CI 0.07-0.42) and the GM tHcy was 6.6 micromol/l (95% CI 3.1-13.9). There is a slight positive correlation between plasma MMA and age in children >1 year (r = 0.211, P < 0.05). Plasma MMA concentrations were significantly higher in children with low Cbl concentrations. No significant difference in MMA, Cbl, tHcy or creatinine concentrations between sexes could be observed. Regression analysis showed that Cbl was the strongest determinant of plasma MMA (regression coefficient -0.414, P < 0.05). The association between MMA and Cbl is stronger at increasing age (P for trend 0.045).


CONCLUSIONS
Plasma Cbl is the main determinant of MMA in this group of Dutch children. The strength of the association increased with increasing age.
Hogeveen
Marije
M
Dept. of Paediatrics, Metabolic and Endocrine Diseases, Radboud University Nijmegen Medical Centre, PO Box 9101, 6500 HB, Nijmegen, The Netherlands. m.hogeveen@cukz.umcn.nl
van Beynum
Ingrid
I
van Rooij
Arno
A
Kluijtmans
Leo
L
den Heijer
Martin
M
Blom
Henk
H
D000293:Adolescent; D000328:Adult; D000375:Aging / Q000097:blood*; D015415:Biomarkers / Q000097:blood; D002648:Child; D002675:Child, Preschool; D003404:Creatinine / Q000097:blood; D003430:Cross-Sectional Studies; D005260:Female; D006710:Homocysteine / Q000097:blood*; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008764:Methylmalonic Acid / Q000097:blood*; D009426:Netherlands; D012016:Reference Values; D012044:Regression Analysis; D014805:Vitamin B 12 / Q000097:blood*; D014806:Vitamin B 12 Deficiency / Q000097:blood / Q000175:diagnosis
D015415:Biomarkers; D006710:Homocysteine; D008764:Methylmalonic Acid; D003404:Creatinine; D014805:Vitamin B 12