BACK TOTOP Browse A-ZSearchBrowse A-ZABCDEFGHIJKLMNOPQRSTUVWXYZ0-9 E-mail FormEmail ResultsName:Email address:Recipients Name:Recipients address:Message: Print-FriendlyBookmarksbookmarks-menuMaple syrup urine diseaseMSUDMaple syrup urine disease (MSUD) is a disorder in which the body cannot break down certain parts of proteins. The urine of people with this condition can smell like maple syrup. Causes Maple syrup urine disease (MSUD) is inherited, which means it is passed down through families. It is caused by a defect in 1 of 3 genes. People with this condition cannot break down the amino acids leucine, isoleucine, and valine. This leads to a buildup of these chemicals in the blood.Amino acidsAmino acids are molecules that combine to form proteins. Amino acids and proteins are the building blocks of life. When proteins are digested or bro...Read Article Now Book Mark Article In the most severe form, MSUD can damage the brain during times of physical stress (such as infection, fever, or not eating for a long time).Some types of MSUD are mild or come and go. Even in the mildest form, repeated periods of physical stress can cause intellectual disability and high levels of leucine to build up.Intellectual disabilityIntellectual disability is a condition diagnosed before age 18 that includes below-average intellectual function and a lack of skills necessary for d...Read Article Now Book Mark Article Symptoms Symptoms of this disorder include:Coma Feeding difficulties Lethargy LethargyFatigue is a feeling of weariness, tiredness, or lack of energy.Read Article Now Book Mark Article Seizures SeizuresA seizure is the physical changes in behavior that occurs during an episode of specific types of abnormal electrical activity in the brain. The term ...Read Article Now Book Mark Article Urine that smells like maple syrup Vomiting Exams and Tests These tests may be done to check for this disorder:Plasma amino acid test Plasma amino acid testPlasma amino acids is a screening test, usually done on infants that looks at the amounts of amino acids in the blood. Amino acids are the building ...Read Article Now Book Mark Article Urine organic acid test Urine organic acid testAminoaciduria is an abnormally high amount of amino acids in the urine. Amino acids are the building blocks for proteins in the body.Read Article Now Book Mark Article Genetic testingThere will be signs of ketosis (buildup of ketones, a by-product of burning fat for energy) and excess acid in the blood (acidosis).KetosisA ketone blood test measures the amount of ketones in the blood. Ketones can also be measured with a urine test.Read Article Now Book Mark Article Treatment When the condition is diagnosed, and during episodes, treatment involves eating a protein-free diet. Fluids, sugars, and sometimes fats are given through a vein (IV). Dialysis through your belly or a vein can be done to reduce the level of abnormal substances in your blood.Long-term treatment requires a special diet. For infants, the diet includes a formula with low levels of the amino acids leucine, isoleucine, and valine. People with this condition must remain on a diet low in these amino acids for life.It is very important to always follow this diet to prevent nervous system (neurological) damage. This requires frequent blood tests and close supervision by a registered dietitian and physician, as well as cooperation by parents of children with the condition. Outlook (Prognosis) This disease can be life threatening if untreated.Even with dietary treatment, stressful situations and illness can still cause high levels of certain amino acids. Death may occur during these episodes. With strict dietary treatment, children have grown into adulthood and can remain healthy. Possible Complications These complications can occur:Neurological damage Coma Death Intellectual disability When to Contact a Medical Professional Contact your health care provider if you have a family history of MSUD and are planning to start a family. Also call your provider right away if you have a newborn who has symptoms of maple syrup urine disease. Prevention Genetic counseling is suggested for people who want to have children and who have a family history of maple syrup urine disease. Many states now screen all newborns with blood testing for MSUD.If a screening test shows that your baby may have MSUD, a follow-up blood test for amino acid levels should be done right away to confirm the disease.Open ReferencesReferencesGallagher RC, Enns GM, Cowan TM, Mendelsohn B, Packman S. Aminoacidemias and organic acidemias. In: Swaiman KF, Ashwal S, Ferriero DM, et al, eds. Swaiman's Pediatric Neurology: Principles and Practice. 6th ed. Philadelphia, PA: Elsevier; 2017:chap 37.Kliegman RM, St. Geme JW, Blum NJ, Shah SS, Tasker RC, Wilson KM. Defects in metabolism of amino acids. In: Kliegman RM, St. Geme JW, Blum NJ, Shah SS, Tasker RC, Wilson KM, eds. Nelson Textbook of Pediatrics. 21st ed. Philadelphia, PA: Elsevier; 2020:chap 103.Merritt JL, Gallagher RC. Inborn errors of carbohydrate, ammonia, amino acid, and organic acid metabolism. In: Gleason CA, Sawyer T, eds. Avery's Diseases of the Newborn. 11th ed. Philadelphia, PA: Elsevier; 2024:chap 29.AllVideoImagesTogA Closer Look Heart-healthy diet - InDepth(In-Depth) Tests for Maple syrup urine disease AminoaciduriaRelated Information Metabolism(Special Topic)Acidosis(Condition)Amino acids(Special Topic)Seizures(Symptoms) Review Date: 4/24/2023 Reviewed By: Anna C. Edens Hurst, MD, MS, Associate Professor in Medical Genetics, The University of Alabama at Birmingham, Birmingham, AL. Review provided by VeriMed Healthcare Network. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team. The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. 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Maple syrup urine diseaseMSUDMaple syrup urine disease (MSUD) is a disorder in which the body cannot break down certain parts of proteins. The urine of people with this condition can smell like maple syrup. Causes Maple syrup urine disease (MSUD) is inherited, which means it is passed down through families. It is caused by a defect in 1 of 3 genes. People with this condition cannot break down the amino acids leucine, isoleucine, and valine. This leads to a buildup of these chemicals in the blood.Amino acidsAmino acids are molecules that combine to form proteins. Amino acids and proteins are the building blocks of life. When proteins are digested or bro...Read Article Now Book Mark Article In the most severe form, MSUD can damage the brain during times of physical stress (such as infection, fever, or not eating for a long time).Some types of MSUD are mild or come and go. Even in the mildest form, repeated periods of physical stress can cause intellectual disability and high levels of leucine to build up.Intellectual disabilityIntellectual disability is a condition diagnosed before age 18 that includes below-average intellectual function and a lack of skills necessary for d...Read Article Now Book Mark Article Symptoms Symptoms of this disorder include:Coma Feeding difficulties Lethargy LethargyFatigue is a feeling of weariness, tiredness, or lack of energy.Read Article Now Book Mark Article Seizures SeizuresA seizure is the physical changes in behavior that occurs during an episode of specific types of abnormal electrical activity in the brain. The term ...Read Article Now Book Mark Article Urine that smells like maple syrup Vomiting Exams and Tests These tests may be done to check for this disorder:Plasma amino acid test Plasma amino acid testPlasma amino acids is a screening test, usually done on infants that looks at the amounts of amino acids in the blood. Amino acids are the building ...Read Article Now Book Mark Article Urine organic acid test Urine organic acid testAminoaciduria is an abnormally high amount of amino acids in the urine. Amino acids are the building blocks for proteins in the body.Read Article Now Book Mark Article Genetic testingThere will be signs of ketosis (buildup of ketones, a by-product of burning fat for energy) and excess acid in the blood (acidosis).KetosisA ketone blood test measures the amount of ketones in the blood. Ketones can also be measured with a urine test.Read Article Now Book Mark Article Treatment When the condition is diagnosed, and during episodes, treatment involves eating a protein-free diet. Fluids, sugars, and sometimes fats are given through a vein (IV). Dialysis through your belly or a vein can be done to reduce the level of abnormal substances in your blood.Long-term treatment requires a special diet. For infants, the diet includes a formula with low levels of the amino acids leucine, isoleucine, and valine. People with this condition must remain on a diet low in these amino acids for life.It is very important to always follow this diet to prevent nervous system (neurological) damage. This requires frequent blood tests and close supervision by a registered dietitian and physician, as well as cooperation by parents of children with the condition. Outlook (Prognosis) This disease can be life threatening if untreated.Even with dietary treatment, stressful situations and illness can still cause high levels of certain amino acids. Death may occur during these episodes. With strict dietary treatment, children have grown into adulthood and can remain healthy. Possible Complications These complications can occur:Neurological damage Coma Death Intellectual disability When to Contact a Medical Professional Contact your health care provider if you have a family history of MSUD and are planning to start a family. Also call your provider right away if you have a newborn who has symptoms of maple syrup urine disease. Prevention Genetic counseling is suggested for people who want to have children and who have a family history of maple syrup urine disease. Many states now screen all newborns with blood testing for MSUD.If a screening test shows that your baby may have MSUD, a follow-up blood test for amino acid levels should be done right away to confirm the disease.Open ReferencesReferencesGallagher RC, Enns GM, Cowan TM, Mendelsohn B, Packman S. Aminoacidemias and organic acidemias. In: Swaiman KF, Ashwal S, Ferriero DM, et al, eds. Swaiman's Pediatric Neurology: Principles and Practice. 6th ed. Philadelphia, PA: Elsevier; 2017:chap 37.Kliegman RM, St. Geme JW, Blum NJ, Shah SS, Tasker RC, Wilson KM. Defects in metabolism of amino acids. In: Kliegman RM, St. Geme JW, Blum NJ, Shah SS, Tasker RC, Wilson KM, eds. Nelson Textbook of Pediatrics. 21st ed. Philadelphia, PA: Elsevier; 2020:chap 103.Merritt JL, Gallagher RC. Inborn errors of carbohydrate, ammonia, amino acid, and organic acid metabolism. In: Gleason CA, Sawyer T, eds. Avery's Diseases of the Newborn. 11th ed. Philadelphia, PA: Elsevier; 2024:chap 29.