As a dietitian, I could readily identify MSUD as "Maple Syrup Urine
Disease", an inborn error of
metabolism.  As more of an LC for the past 15 years rather than an RD,
 I had to do some digging to find out what it
specifically meant!!  Here's what I found out:

Also known as branched-chain ketoaciduria, MSUD infants are
identified shortly after birth by the
maple syrup ordor of the body and urine.  They become ill shortly
after birth - feeding difficulties,
vomiting, convulsions are followed by death.  The branched-chain
amino acids - valine, leucine and
isoleucine - tranform and turn into keto acids.  In this inborn error
of metabolism, these keto acids
cannot undergo oxidative decarboxylation and the keto acids along
with free amino acids build up in
the blood and subsequently spill over into the urine.

Treatment must be instituted early in life to avoid mental
retardation.  Control is much more difficult
than in the case of PKU.  Plasma levels of each amino acid must be
regulated individually.  The levels
are not easily stabilized, especially in times of illness.
Peritoneal dialysis may be used to reduce blood
levels of the amino acids.

As far as diet, all of the three amino acids are essential, meaning
they must be supplied in the diet for
normal growth and development - they will not be manufactured by the
body.  In normal infants,
excesses are not a problem.  In MSUD, the baby must get the amount
required for normal growthe and
development, but not extra.  A special formula which is void of
leucine, isoleucine and valine can be
used and then the minimum amount of the amino acids added back to the
diet along with monitoring
serum blood levels.

As far as breastfeeding is concerned, BM contains all of these amino
acids, naturally, because they are
essential amino acids needed for growth.  From the tables in Lawrence,
 it appears mature milk is lower
in the amino acids than colustrum (p. 505 3rd edition).  I suspect
mother nature has provided more than
the minimum and this could cause a problem for the MSUD infant.  It
might be possible to try BF after
the mature milk is in and monitoring the serum levels as indicated
above.  I do have my doubts, though
and think the levels may be too high for a MSUD infant to handle on a
regular basis.    Hope this is
helpful.  Theresa Gutsch, Ms, RD, CLE