Maple Syrup Urine Disease (MSUD)

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UniProtKB/Swiss-Prot ⁷³ Maple syrup urine disease: A metabolic disorder due to an enzyme defect in the catabolic pathway of the branched-chain amino acids leucine, isoleucine, and valine. Accumulation of these 3 amino acids and their corresponding keto acids leads to encephalopathy and progressive neurodegeneration. Clinical features include mental and physical retardation, feeding problems, and a maple syrup odor to the urine. The keto acids of the branched- chain amino acids are present in the urine. If untreated, maple syrup urine disease can lead to seizures, coma, and death. The disease is often classified by its pattern of signs and symptoms. The most common and severe form of the disease is the classic type, which becomes apparent soon after birth. Variant forms of the disorder become apparent later in infancy or childhood and are typically milder, but they still involve developmental delay and other medical problems if not treated.

Maple syrup urine disease 2: A metabolic disorder due to an enzyme defect in the catabolic pathway of the branched-chain amino acids leucine, isoleucine, and valine. Accumulation of these 3 amino acids and their corresponding keto acids leads to encephalopathy and progressive neurodegeneration. Clinical features include mental and physical retardation, feeding problems, and a maple syrup odor to the urine. The keto acids of the branched- chain amino acids are present in the urine. If untreated, maple syrup urine disease can lead to seizures, coma, and death. The disease is often classified by its pattern of signs and symptoms. The most common and severe form of the disease is the classic type, which becomes apparent soon after birth. Variant forms of the disorder become apparent later in infancy or childhood and are typically milder, but they still involve developmental delay and other medical problems if not treated.

Maple syrup urine disease 1a: A metabolic disorder due to an enzyme defect in the catabolic pathway of the branched-chain amino acids leucine, isoleucine, and valine. Accumulation of these 3 amino acids and their corresponding keto acids leads to encephalopathy and progressive neurodegeneration. Clinical features include mental and physical retardation, feeding problems, and a maple syrup odor to the urine. The keto acids of the branched- chain amino acids are present in the urine. If untreated, maple syrup urine disease can lead to seizures, coma, and death. The disease is often classified by its pattern of signs and symptoms. The most common and severe form of the disease is the classic type, which becomes apparent soon after birth. Variant forms of the disorder become apparent later in infancy or childhood and are typically milder, but they still involve developmental delay and other medical problems if not treated.

Maple syrup urine disease 1b: A metabolic disorder due to an enzyme defect in the catabolic pathway of the branched-chain amino acids leucine, isoleucine, and valine. Accumulation of these 3 amino acids and their corresponding keto acids leads to encephalopathy and progressive neurodegeneration. Clinical features include mental and physical retardation, feeding problems, and a maple syrup odor to the urine. The keto acids of the branched- chain amino acids are present in the urine. If untreated, maple syrup urine disease can lead to seizures, coma, and death. The disease is often classified by its pattern of signs and symptoms. The most common and severe form of the disease is the classic type, which becomes apparent soon after birth. Variant forms of the disorder become apparent later in infancy or childhood and are typically milder, but they still involve developmental delay and other medical problems if not treated.

MalaCards based summary: Maple Syrup Urine Disease, also known as bckd deficiency, is related to dihydrolipoamide dehydrogenase deficiency and intermediate maple syrup urine disease, and has symptoms including ataxia, vomiting and headache. An important gene associated with Maple Syrup Urine Disease is BCKDHA (Branched Chain Keto Acid Dehydrogenase E1 Subunit Alpha), and among its related pathways/superpathways are Metabolism and Regulation of expression of SLITs and ROBOs. The drugs Dapagliflozin and Insulin, Globin Zinc have been mentioned in the context of this disorder. Affiliated tissues include brain, heart and liver, and related phenotypes are intellectual disability and seizure

Orphanet ⁵⁸ Maple syrup urine disease: A rare inherited disorder of branched-chain amino acid metabolism classically characterized by poor feeding, lethargy, vomiting and a maple syrup odor in the cerumen (and later in urine) noted soon after birth, followed by progressive encephalopathy and central respiratory failure if untreated. The four overlapping phenotypic subtypes are: classic, intermediate, intermittent and thiamine-responsive MSUD.

Classic maple syrup urine disease: Classic maple syrup urine disease (classic MSUD) is the most severe and probably common form of MSUD (see this term) characterized by a maple syrup odor in the cerumen at birth, poor feeding, lethargy and focal dystonia, followed by progressive encephalopathy and central respiratory failure if untreated.

Intermittent maple syrup urine disease: Intermittent maple syrup urine disease (intermittent MSUD) is a mild form of MSUD (see this term) where patients (when well) are asymptomatic with normal levels of branched-chain amino acids (BCAAs) but with catabolic stress are at risk of acute decompensation with ketoacidosis, which can lead to cerebral edema and coma if untreated.

Thiamine-responsive maple syrup urine disease: Thiamine-responsive maple syrup urine disease (thiamine-responsive MSUD) is a less severe variant of MSUD (see this term) that manifests with a phenotype similar to intermediate MSUD (see this term) but that responds positively to treatment with thiamine.

GARD: ¹⁹ Maple syrup urine disease (MSUD) occurs when the body is unable to breakdown certain parts of proteins. This leads to the build-up of toxic substances that can cause organ and brain damage. There are several forms of MSUD. The most common is the classic or infantile form. Symptoms of the classic form of MSUD start in early infancy and include poor feeding, irritability, extra sleepiness, and muscle spasms. The earwax and urine of infants with MSUD smells like maple syrup. The symptoms of other forms of MSUD start in adolescence or adulthood. MSUD is caused by genetic variants in the BCKDHA, BCKDHB, or DBT genes. It is inherited in an autosomal recessive pattern. Diagnosis of MSUD is based on the symptoms, clinical exam, and blood and urine testing. MSUD is often diagnosed based on the results of a newborn screening test.

MedlinePlus Genetics: ⁴² Maple syrup urine disease is an inherited disorder in which the body is unable to process certain protein building blocks (amino acids) properly. The condition gets its name from the distinctive sweet odor of affected infants' urine. It is also characterized by poor feeding, vomiting, lack of energy (lethargy), abnormal movements, and delayed development. If untreated, maple syrup urine disease can lead to seizures, coma, and death.Maple syrup urine disease is often classified by its pattern of signs and symptoms. The most common and severe form of the disease is the classic type, which becomes apparent soon after birth. Variant forms of the disorder become apparent later in infancy or childhood and are typically milder, but they still lead to delayed development and other health problems if not treated.

OMIM®: ⁵⁷ The major clinical features of maple syrup urine disease are mental and physical retardation, feeding problems, and a maple syrup odor to the urine. The keto acids of the branched-chain amino acids are present in the urine, resulting from a block in oxidative decarboxylation. There are 5 clinical subtypes of MSUD: the 'classic' neonatal severe form, an 'intermediate' form, an 'intermittent' form, a 'thiamine-responsive' form, and an 'E3-deficient with lactic acidosis' form (246900). All of these subtypes can be caused by mutations in any of the 4 genes mentioned above, except for the E3-deficient form, which is caused only by mutation in the E3 gene (Chuang and Shih, 2001). (248600) (Updated 08-Dec-2022)

Disease Ontology: ¹¹ An organic acidemia that is caused by a deficiency of decarboxylase leading to high concentrations of valine, leucine, isoleucine, and alloisoleucine in the blood, urine, and cerebrospinal fluid and characterized by an odor of maple syrup to the urine, vomiting, hypertonicity, severe mental retardation, seizures, and eventually death unless the condition is treated with dietary measures.

Wikipedia: ⁷⁵ Maple syrup urine disease (MSUD) is an autosomal recessive metabolic disorder affecting branched-chain... more...

Clinical features from OMIM®:

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