Maple syrup urine disease: Difference between revisions
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[[File:L-Leucine.svg| | {{SI}} | ||
{{Infobox medical condition | |||
| name = Maple syrup urine disease | |||
| image = [[File:L-Leucine.svg|left|thumb|Chemical structure of [[leucine]], one of the [[branched-chain amino acids]] involved in the disease]] | |||
| caption = | |||
| synonyms = Branched-chain ketoaciduria | |||
| pronounce = | |||
| specialty = [[Medical genetics]] | |||
| symptoms = Sweet-smelling urine, poor feeding, vomiting, lethargy, developmental delay | |||
| onset = Infancy | |||
| duration = Lifelong | |||
| types = Classic, Intermediate, Intermittent, Thiamine-responsive | |||
| causes = [[Genetic mutation]] in [[BCKDHA]], [[BCKDHB]], [[DBT]], or [[DLD]] genes | |||
| risks = Family history | |||
| diagnosis = [[Newborn screening]], [[urine test]], [[genetic testing]] | |||
| differential = [[Phenylketonuria]], [[homocystinuria]], [[organic acidemia]] | |||
| prevention = None | |||
| treatment = [[Dietary restriction]] of [[branched-chain amino acids]], [[thiamine]] supplementation | |||
| medication = | |||
| prognosis = Variable, depends on type and management | |||
| frequency = 1 in 185,000 worldwide; higher in certain populations | |||
| deaths = | |||
}} | |||
'''Maple syrup urine disease''' ('''MSUD''') is a rare [[autosomal recessive]] [[metabolic disorder]] affecting [[branched-chain amino acids]]. It is named for the distinctive sweet odor of affected infants' urine, which is reminiscent of [[maple syrup]]. The condition is caused by a deficiency in the branched-chain alpha-keto acid dehydrogenase complex, leading to the accumulation of the amino acids [[leucine]], [[isoleucine]], and [[valine]] in the body. | |||
==Signs and Symptoms== | ==Signs and Symptoms== | ||
The symptoms of MSUD typically appear in the first few days of life. They include poor feeding, vomiting, lethargy, and developmental delay. If untreated, the condition can lead to [[seizures]], [[coma]], and [[death]]. The characteristic maple syrup odor in the urine is a key diagnostic feature. | The symptoms of MSUD typically appear in the first few days of life. They include poor feeding, vomiting, lethargy, and developmental delay. If untreated, the condition can lead to [[seizures]], [[coma]], and [[death]]. The characteristic maple syrup odor in the urine is a key diagnostic feature. | ||
==Genetics== | ==Genetics== | ||
MSUD is inherited in an autosomal recessive pattern, meaning that both copies of the gene in each cell have mutations. The parents of an individual with MSUD each carry one copy of the mutated gene but typically do not show signs and symptoms of the condition. | MSUD is inherited in an autosomal recessive pattern, meaning that both copies of the gene in each cell have mutations. The parents of an individual with MSUD each carry one copy of the mutated gene but typically do not show signs and symptoms of the condition. | ||
==Pathophysiology== | ==Pathophysiology== | ||
The disease is caused by mutations in the genes that encode the branched-chain alpha-keto acid dehydrogenase complex. This complex is responsible for the catabolism of the branched-chain amino acids leucine, isoleucine, and valine. When this complex is deficient or non-functional, these amino acids and their corresponding keto acids accumulate in the blood and urine, leading to the symptoms of MSUD. | The disease is caused by mutations in the genes that encode the branched-chain alpha-keto acid dehydrogenase complex. This complex is responsible for the catabolism of the branched-chain amino acids leucine, isoleucine, and valine. When this complex is deficient or non-functional, these amino acids and their corresponding keto acids accumulate in the blood and urine, leading to the symptoms of MSUD. | ||
==Diagnosis== | ==Diagnosis== | ||
Diagnosis of MSUD is typically made through newborn screening programs that measure the levels of branched-chain amino acids in the blood. Confirmatory testing involves measuring enzyme activity in cultured cells or identifying mutations in the genes associated with the disease. | Diagnosis of MSUD is typically made through newborn screening programs that measure the levels of branched-chain amino acids in the blood. Confirmatory testing involves measuring enzyme activity in cultured cells or identifying mutations in the genes associated with the disease. | ||
==Treatment== | ==Treatment== | ||
The primary treatment for MSUD is a carefully controlled diet that limits the intake of branched-chain amino acids. This diet must be maintained for life to prevent the accumulation of toxic substances. In some cases, [[liver transplantation]] has been used as a treatment, as the liver contains the enzymes necessary to break down the branched-chain amino acids. | The primary treatment for MSUD is a carefully controlled diet that limits the intake of branched-chain amino acids. This diet must be maintained for life to prevent the accumulation of toxic substances. In some cases, [[liver transplantation]] has been used as a treatment, as the liver contains the enzymes necessary to break down the branched-chain amino acids. | ||
==Prognosis== | ==Prognosis== | ||
With early diagnosis and proper management, individuals with MSUD can lead relatively normal lives. However, they must adhere strictly to dietary restrictions and be monitored regularly for signs of metabolic imbalance. | With early diagnosis and proper management, individuals with MSUD can lead relatively normal lives. However, they must adhere strictly to dietary restrictions and be monitored regularly for signs of metabolic imbalance. | ||
==See also== | |||
== | |||
* [[Metabolic disorder]] | * [[Metabolic disorder]] | ||
* [[Amino acid]] | * [[Amino acid]] | ||
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* [[Liver transplantation]] | * [[Liver transplantation]] | ||
[[Category:Metabolic disorders]] | [[Category:Metabolic disorders]] | ||
[[Category:Genetic disorders]] | [[Category:Genetic disorders]] | ||
[[Category:Pediatrics]] | [[Category:Pediatrics]] | ||
{{medicine-stub}} | {{medicine-stub}} | ||
Latest revision as of 03:45, 8 April 2025
Editor-In-Chief: Prab R Tumpati, MD
Obesity, Sleep & Internal medicine
Founder, WikiMD Wellnesspedia &
W8MD medical weight loss NYC and sleep center NYC
| Maple syrup urine disease | |
|---|---|
 | |
| Synonyms | Branched-chain ketoaciduria |
| Pronounce | |
| Specialty | Medical genetics |
| Symptoms | Sweet-smelling urine, poor feeding, vomiting, lethargy, developmental delay |
| Complications | N/A |
| Onset | Infancy |
| Duration | Lifelong |
| Types | Classic, Intermediate, Intermittent, Thiamine-responsive |
| Causes | Genetic mutation in BCKDHA, BCKDHB, DBT, or DLD genes |
| Risks | Family history |
| Diagnosis | Newborn screening, urine test, genetic testing |
| Differential diagnosis | Phenylketonuria, homocystinuria, organic acidemia |
| Prevention | None |
| Treatment | Dietary restriction of branched-chain amino acids, thiamine supplementation |
| Medication | |
| Prognosis | Variable, depends on type and management |
| Frequency | 1 in 185,000 worldwide; higher in certain populations |
| Deaths | |
Maple syrup urine disease (MSUD) is a rare autosomal recessive metabolic disorder affecting branched-chain amino acids. It is named for the distinctive sweet odor of affected infants' urine, which is reminiscent of maple syrup. The condition is caused by a deficiency in the branched-chain alpha-keto acid dehydrogenase complex, leading to the accumulation of the amino acids leucine, isoleucine, and valine in the body.
Signs and Symptoms[edit]
The symptoms of MSUD typically appear in the first few days of life. They include poor feeding, vomiting, lethargy, and developmental delay. If untreated, the condition can lead to seizures, coma, and death. The characteristic maple syrup odor in the urine is a key diagnostic feature.
Genetics[edit]
MSUD is inherited in an autosomal recessive pattern, meaning that both copies of the gene in each cell have mutations. The parents of an individual with MSUD each carry one copy of the mutated gene but typically do not show signs and symptoms of the condition.
Pathophysiology[edit]
The disease is caused by mutations in the genes that encode the branched-chain alpha-keto acid dehydrogenase complex. This complex is responsible for the catabolism of the branched-chain amino acids leucine, isoleucine, and valine. When this complex is deficient or non-functional, these amino acids and their corresponding keto acids accumulate in the blood and urine, leading to the symptoms of MSUD.
Diagnosis[edit]
Diagnosis of MSUD is typically made through newborn screening programs that measure the levels of branched-chain amino acids in the blood. Confirmatory testing involves measuring enzyme activity in cultured cells or identifying mutations in the genes associated with the disease.
Treatment[edit]
The primary treatment for MSUD is a carefully controlled diet that limits the intake of branched-chain amino acids. This diet must be maintained for life to prevent the accumulation of toxic substances. In some cases, liver transplantation has been used as a treatment, as the liver contains the enzymes necessary to break down the branched-chain amino acids.
Prognosis[edit]
With early diagnosis and proper management, individuals with MSUD can lead relatively normal lives. However, they must adhere strictly to dietary restrictions and be monitored regularly for signs of metabolic imbalance.
See also[edit]
