Infants cobalamins

Scalabrino G (2005) Cobalamin (vitamin B12) in subacute combined degeneration and beyond tiadional interpretations and novel theories. Exp Neurol 192(2) 463 79 Scalabrino G, BucceUato FR, Veber D, Mutti E (2003) New basis of the neurotrophic action of vitamin B12. Clin Chem Lab Med 41(11) 1435-1437 Shih JJ, Kornblum H, Shewmon DA (1996) Global brain dysfunction in an infant with pyridox-ine dependency evaluation with EEG, evoked potentials, MRI, and PET. Neurology 47(3) 824-826... 

A large number of disorders are associated with cobalamin deficiency in infancy or childhood. Of these, the most commonly encountered is the Imerslund-Graesbeck syndrome, a condition that is characterized by inability to absorb vitamin B,2, with or without IF, and proteinuria. It appears to be due to an inability of intestinal mucosa to absorb the vitamin B,2 IF complex. The second most common of these is congenital deficiency of gastric secretion of IF. Very rarely, congenital deficiency of vitamin B12 in a breast-fed infant is due to deficiency of vitamin B12 in maternal breast milk as a result of unrecognized pernicious anemia in the mother. This is rare because most women with undiagnosed and untreated pernicious anemia are infertile. Additionally, there are some rare methylmalonic acidemias (acidurias) caused by inborn errors in homocysteine and methionine metabolism that are responsible for disorders in vitamin B status. ... 

Postmortem studies indicate that the infant had methylmalonic acidemia, cobalamin A a treatable form of B,2 metabolism. Treatment with cobalamin injections and diet typically yields a good outcome. 

V.B12 occurs predominantly in animal tissues and animal products. It is synthesized principally by bacteria. Green plants contain little or no V.B,2. Deficiency symptoms are sometimes observed in strict vegetarians, most often in breast-fed infants whose mothers consume no animal products. The body reserves of cobalamin are usually so large that an adult can survive for many years on them in the absence of a dietary intake. 

The study by Hay et at. (2011) on the cobalamin status of healthy infants (breastfeeding and weaning up to two-years-old) showed that vitamin B12 status i.e. holoTC levels) remained significantly lower in breastfed than in non-breastfed infants. Maternal holoTC concentrations were the best predictor of a newborn s cobalamin status. Moreover, cobalamin intake correlated with serum holoTC levels in healthy toddlers (Hay et al. 2011). 

The assessment of serum holoTC concentrations is clinically and diagnostically useful. In fact, the biologically active form of vitamin B12 represents the best predictor of cobalamin status from infancy to old age maternal holoTC concentrations can predict newborns vitamin status, serum holoTC levels correlate with infants dietary cobalamin intake, holoTC measurement is useful to diagnose cognitively impaired patients (Refsum et al. 2006). 

---