Maple Syrup Urine Disease
MSUD is a condition that occurs when the body lacks an enzyme needed to break down protein. When this enzyme is missing, parts of the protein build up in the body and cause damage to the nervous system, especially the brain. If left untreated, MSUD can result in mental retardation, seizures, coma, and even death.
Everyone needs protein for growth and repair of body tissues, but the body cannot use the protein in food until it is broken down into smaller parts. These "smaller parts" of protein are called amino acids. In MSUD, three of these amino acids cannot be broken down . These three amino acids are called leucine (LEU), isoleucine (ILE), and valine (VAL)
They should be broken down by an enzyme called branched chain alpha-keto acid dehydrogenase (BCKAD). In people with MSUD the BCKAD enzyme either is missing or does not work well. As a result, LEU, ILE, and VAL levels build up and damage the body, especially the brain.
Cause
MSUD is caused by a change in one specific genetic instruction (gene) and is an inherited disorder. The mode of inheritance is called autosomal recessive, meaning that each parent carries a gene for the disorder. A person with the disorder has two copies of the changed gene: one from the mother and one from the father.
Diagnosis
Infants, children and even adults that exhibit symptoms of MSUD can be identified with a simple blood test that measures the amount of leucine in the blood. In California, most babies with this condition are found by the Newborn Screening Program. Further testing measuring the amount and type of enzyme activity is done to confirm the diagnosis. Through early detection and prompt treatment, many serious effects of MSUD can be prevented.
Treatment
The goal of MSUD treatment is to keep the level of leucine in the blood as close to normal as possible order to avoid any of the poor consequences of having high levels. The treatment itself consists of four main parts: diet, formula, supplements, monitoring.
Diet: Please keep in mind that when we refer to "eating" that this includes any eating, drinking, swallowing, and chewing. When we refer to "foods," this includes all foods, drinks, medications, and even gum.
The first aim in treatment is to cut down on the amount of protein that the person eats. This means that people with MSUD must learn what types of foods are highest in protein and avoid these. Some examples of foods high in protein include all types of meat (e.g., chicken, pork, beef, seafood), all types of dairy (e.g., milk, yogurt, cheese, whipped cream, ice cream, etc.), all types of beans and nuts (e.g., soybeans, pinto beans, peanuts, etc.), and eggs.
People with MSUD must also learn what foods have some amount of protein and ways to measure how much. Each individual, depending on the severity of their disorder, is given a daily limit of the protein they can eat. It is okay for people with MSUD to eat some protein because, unlike an allergy, the protein will not cause them to have an "allergic" reaction. In fact, people with MSUD must eat some protein every day as everyone needs some in order to get some leucine, isoleucine and valine for growth and development. The trick is not to eat too much. This is done by learning to count and keep track of the amount they consume throughout the day.
One of the main problems in following the MSUD diet is nutritional balance. Foods that are low in protein tend to be high in either fat or sugar or both. While some low-protein foods can be very nutritious, such as low-protein vegetables and fruit, others offer mostly "empty" calories. Foods that are high in empty calories supply a person with calories, but little nutrition. These calories are often needed for energy and growth but, when consumed in large amounts, can lead to obesity.
Another problem is creating enough variety in the diet, especially for picky eaters. One way to increase variety is to eat low-protein specialty products. For instance, instead of avoiding all breads, pastas, and rice (which often have too much protein), people with MSUD can try some of the special low-protein versions of these foods. There are also many other types of low protein foods available, such as cheese, peanut butter, pizza, etc. As of July 2000, California State law (Senate Bill #148) requires all health insurance companies to provide low-protein specialty foods free of charge to all patients with a condition called PKU. Kaiser Permanente has expanded this requirement to include patients with any metabolic condition requiring a low-protein diet. The Regional Metabolic Clinic has contracted with several different specialty food companies to provide these products. In order not to be charged for these products, patients must fill out RMC order forms and return them to the clinic for review and approval. The coordinators will then forward these forms on to the company(ies) and the food will be delivered directly to the patient's home. Limit: $2500 per patient per year.Formula: The second part of the treatment for MSUD requires a special protein formula. MSUD formulas are special because they contain all the amino acids a person needs, except leucine, isoleucine and valine. It is almost impossible to get enough protein to stay healthy on a MSUD diet alone. Therefore, people with MSUD need to take formula in order to get enough of the protein without too much leucine, isoleucine and valine. The MSUD formulas are also fortified with essential vitamins and minerals. Fortunately, today there are several different formulas to choose from, including both drinks and bars.
Supplements:
Thiamin - Some forms of MSUD can be treated with high doses of one of the B-vitamins called thiamin. Thiamin is a co-factor that helps the BCKAD enzyme work better. Whether or not a patient has the thiamin-responsive form of MSUD is determined early in the treatment process. If the patient does not have this form of MSUD, no amount of thiamin will help. We strongly advise against self-treatment as it may cause unwanted side-effects or interfere with other treatments.
Isoleucine - Due to the protein restriction of the diet, some people with MSUD develop a deficiency of isoleucine (one of the essential branched-chain amino acids). When this happens, isoleucine supplementation is recommended to correct the deficiency.
Valine - Due to the protein restriction of the diet, some people with MSUD develop a deficiency of valine (one of the essential branched-chain amino acids). When this happens, valine supplementation is recommended to correct the deficiency.Monitoring: The final part of the treatment for MSUD is monitoring, in order to know whether the other three parts of the treatment (diet, formula, supplements) are actually working to maintain normal levels of leucine, isoleucine, and valine. It is best to find this out before the person with MSUD experiences any of the possible bad effects (as discussed above). Growth measurements and laboratory studies are obtained on a routine basis.
Blood tests - Monitoring is done by testing the levels of all the amino acids in the blood on a regular basis. The blood samples are drawn through a needle at the hospital lab and sent down to the Metabolic Laboratory at Kaiser in Los Angeles for testing. It can take several days to a week to receive the results.
For all blood tests, a 3-day diet record is recommended. To complete a diet record all the food eaten over the period of three days must be written down along with the amount eaten. The blood test(s) should be taken on the 4th day, right after the diet record is completed. The diet record is an important part of interpreting the test results. For instance, if the leucine level is high, is it because the person is eating too much protein or too little? It is hard to get an accurate picture of what is happening inside the body without having the information provided by the diet record.
Other tests - Patients are regularly weighed and measured at the metabolic clinic and during regular doctor visits in order to monitor their growth and development. School reports can also help identify any learning disabilities.
RESOURCES
MSUD Family Support Group - A support group with worldwide membership. Provides opportunities for support and personal contact for those with MSUD and their families. Distributes information and raises public awareness of MSUD. Strengthens the liaison between families and professionals. Supports newborn screening programs and research for MSUD.
Genetics Home Reference: Maple Syrup Urine Disease - Online information about MSUD provided by the U.S. National Library of Medicine. Also includes links to many related sites.
Reference Books
Low Protein Cookery for PKU (Please note: this book is helpful for all low-pro diets.)
by Virginia Schuett
Published by the University of Wisconsin Press, Madison, WN, 1997
Available through Kaiser's Regional Metabolic Clinic
The Complete IEP Guide published by Nolo Press
This book explains every nuance of the IEP process in lay terms. It provides clear concise explanations, definitions, and descriptions backed by legal codes (code reference numbers are included after every section). It also includes practical suggestions on how to deal with any problems that may arise.
How to Teach Nutrition to Kids
by Connie Liakos Evers, MS, RD
Published by 24 Carrot Press, Tigard, OR, 1995
Positive Discipline
By Jane Nelson, EdD
Published by Ballantine Books, New York, NY
Positive Discipline: The First Three Years
By Jane Nelson, EdD
Published by Ballantine Books, New York, NY
Positive Discipline for PreSchoolers
By Jane Nelsen, EdD, Cheryl Erwin, & Roslyn Duffy
Positive Discipline for Teenagers
By Jane Nelson, EdD, and Lynn Lott, MA
Published by Prima Publishing, Roseville, CA, 2000
Positive Time Out and 50 Other Ways to Avoid Power Struggles in Homes and Classrooms
By Jane Nelsen, EdD
Social Security Disability: Getting & Keeping Your Benefits published by Nolo Press
A legal guidebook to navigating the Social Security system written in plain-English. Helps the layperson to understand Supplemental Security Income (SSI) and Social Security Disability Insurance (SSDI) and the laws behind them (includes legal reference codes after each section).
Temperament Tools: Working with Your Child's Inborn Traits
By Helen Neville and Diane Clark Johnson
Published by Parenting Press, Inc., Seattle, WA, 1998
We're Different, We're the Same by Bobbi J. Kates. Illustrated by Joe Mathieu.
Published in 1992 by Random House. Suggested ages: 4-8
Sesame Street characters learn to appreciate their differences and discover that they still have many things in common.
Why Can't I Eat That!: Helping Kids Obey Medical Diets
By John F. Taylor, PhD, and R. Sharon Latta
Published by R & E Publishers, Saratoga, CA, 1987