child may also be given more frequent blood tests
during this period.
Function
The function of the special dietary regimen and
products for maple syrup urine disease is to prevent
recurrent metabolic crises in the patient and associated
damage to the central nervous system so that the
patient can survive infancy, develop normally, and
have a normal life expectancy.
Benefits
The benefits of strict adherence to the MSUD diet
are normal physical and intellectual development and
a normal life span with no limitations on activity.
Several patients diagnosed with MSUD as children
have been able to complete their education, marry,
and have children without complications. The lon-
gest-lived patient with MSUD as of 2007 has been
followed for over 40 years and is still in good health.
Precautions
Children with MSUD must be taught from an
early age that strict adherence to their dietary regimen
is critical to their health and growth, and that they
must take responsibility for avoiding high-protein
foods and otherwise controlling their diets.
Special care must be taken with even minor ill-
nesses or infections, as the risk of an acute episode of
MSUD is increased at these times.
Children and adolescents with MSUD may occa-
sionally need psychotherapy or medications to cope
with the anxiety and depression that often accompany
diseases requiring careful attention to diet.
Risks
Failure to comply with the MSUD diet puts the
patient at risk of elevated blood levels of BCAAs,
subsequent swelling of brain tissue, seizures, and
death from respiratory failure.
Research and general acceptance
Studies published since the late 1960s indicate that
dietary restriction of branched-chain amino acids is an
effective and low-risk approach to managing MSUD.
A 2005 study of the new line of Vitaflo products found
that the four patients in the study not only liked the
taste, texture, and appearance of Vitaflo Express, but
found it ‘‘very easy to prepare.’’ In addition, the
researchers found that leucine concentrations improved
in all subjects; three of the four patients improved to
the point that they could add more natural protein to
their diets.Resources
BOOKS
Chuang, David T., and Vivian E. Shih. ‘‘Maple Syrup Urine
Disease (Branched-Chain Ketoaciduria).’’ Chapter 87
in Charles R. Scriver, ed., et al.,The Metabolic and
Molecular Bases of Inherited Disease, 8th ed. New York:
McGraw-Hill, 2001.
PERIODICALS
Bodamer, Olaf A., MD, and Brendan Lee, MD, PhD.
‘‘Maple Syrup Urine Disease.’’eMedicine, March 29,- Available online at http://www.emedicine.com/
ped/topic1368.htm.
Hallam, P., M. Lilburn, and P. J. Lee. ‘‘A New Protein
Substitute for Adolescents and Adults with Maple
Syrup Urine Disease (MSUD).’’Journal of Inherited
Metabolic Disease28 (October 2005): 665–672.
Kark, Pieter R., MD, and Tarakad S. Ramachandran, MD.
‘‘Inherited Metabolic Disorders.’’eMedicine, December
8, 2006. Available online at http://www.emedicine.com/
neuro/topic680.htm.
le Roux, C., E. Murphy, M. Lilburn, and P. J. Lee. ‘‘The
Longest-Surviving Patient with Classical Maple Syrup
Urine Disease.’’Journal of Inherited Metabolic Disease
29 (February 2006): 190–194.
Menkes, J. H., P. L. Hurst, and J. M. Craig. ‘‘A New Syn-
drome: Progressive Familial Infantile Cerebral Dys-
function with an Unusual Urinary Substance.’’
Pediatrics14 (November 1954): 462–467.
Morton, D. H., K. A. Strauss, D. L. Robinson, et al.
‘‘Diagnosis and Treatment of Maple Syrup Disease: A
Study of 36 Patients.’’Pediatrics109 (June 2002): 999–
Snyderman, S. E. ‘‘The Therapy of Maple Syrup Urine
Disease.’’American Journal of Diseases of Children 113
(January 1967): 68–73.
Snyderman, S. E., P. M. Norton, E. Roitman, and L. E.
Holt, Jr. ‘‘Maple Syrup Urine Disease, with Particular
Reference to Dietotherapy.’’Pediatrics34 (October
1964): 454–472.
OTHER
Online Mendelian Inheritance in Man, OMIM. Baltimore,
MD: Johns Hopkins University. MIM Number:
ndash248600, Maple Syrup Urine Disease: June 13,
- Available online at http://www.ncbi.nlm.nih.gov/
entrez/dispomim.cgi?id=248600 (accessed March 7,
2007).
Strauss, Kevin A., MD, Erik G. Puffenberger, PhD, and D.
Holmes Morton, MD. ‘‘Maple Syrup Urine Disease.’’
GeneReviews, January 30, 2006. Available online at
http://www.genetests.org/ (accessed March 7, 2007).
The authors are staff members of the Clinic for Special
Children in Strasburg, PA.GeneReviewsis an online
resource of current research about genetic disorders,
Maple syrup urine disease