title: Methylmalonic acid values in healthy Dutch children.
abstract: 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.
authors: 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
authors: Marije
authors: M
authors: Hogeveen
authors: Ingrid
authors: I
authors: van Beynum
authors: Arno
authors: A
authors: van Rooij
authors: Leo
authors: L
authors: Kluijtmans
authors: Martin
authors: M
authors: den Heijer
authors: Henk
authors: H
authors: Blom
mesh_terms: 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
chemical_list: D015415:Biomarkers; D006710:Homocysteine; D008764:Methylmalonic Acid; D003404:Creatinine; D014805:Vitamin B 12