Maple Syrup Urine Disease
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Synonyms of Maple Syrup Urine Disease
- BCKD Deficiency
- Branched Chain Alpha-Ketoacid Dehydrogenase Deficiency
- Branched Chain Ketonuria I
- Classical Maple Syrup Urine Disease
- Classic Maple Syrup Urine Disease
- Intermediate Maple Syrup Urine Disease
- Intermittent Maple Syrup Urine Disease
- Thiamine-Responsive Maple Syrup Urine Disease
Maple syrup urine disease (MSUD) is a rare genetic disorder characterized by deficiency of certain enzymes (branched-chain alpha-keto acid dehydrogenase complex) required to breakdown (metabolize) specific amino acids in the body. Because these amino acids are not metabolized, they, along with their various byproducts, abnormally accumulate in the cells and fluids of the body. Such accumulation can cause a variety of symptoms including lethargy, irritability, poor feeding, abnormal movements and a characteristic odor of maple syrup in the earwax (cerumen), sweat and urine of affected individuals. In addition, if untreated various neurological complications including seizures, coma and brain damage may occur. Failure to promptly detect and treat MSUD can lead to life-threatening complications. However, the disorder can be successfully managed through a specialized diet. Even with treatment affected individuals remain at risk for developing episodes of acute illness (metabolic crisis) often triggered by infection, injury, failure to eat (fasting) or psychological stress. During these episodes there is a rapid, sudden spike in amino acid levels necessitating immediate medical intervention.
At least four subtypes of MSUD have been identified in the medical literature. Some researchers include a fifth subtype, although other researchers consider this a separate distinct disorder. The various subtypes of MSUD have different levels of residual enzyme activity, different severity, and different ages of onset. All forms are inherited as autosomal recessive traits.
Maple Syrup Urine Disease Resources
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