Human milk would be a perfect source of cobalamin, it contains
methylcobalamin, a readily usable form.  The problem with this particular
infant is that he is missing one of the enzymnes that reduce cobalamin
from the dietary 3+ state to the usable 1+ state.  This means that he
cannot use the cobalamin he takes in.  One of the important functions of
cobalamin is that it is converted into succinyl co-enzyme A, which is
essential for the breakdown of isoleucine, methoionine, valine and
threonine.  Without cobalamin, isoleucine and valine yield homocystine;
and methylmalonic acid cannot be converted into succinyl coA, and builds
up in the bloodstream.  Thus these kids have both homocystinuria and
methylmalonic aciduria.  Not a good mileau for a growing brain.
        What I was wondering specifically was whether the methylcobalamin
in human milk would help to bypass the missing enzyme, and whether the
levels of the 4 above amino acids would be low enough for this baby to
get at least some human milk, like babies with phenylketonuria (PKU).
Any takers?
--
Catherine Watson Genna, IBCLC  NYC  [log in to unmask]