Maple Syrup Urine Disease

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Maple Syrup Urine Disease

• Advanced Biochemistry 2009

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Background

• Inherited disease
• Occurs in infants within the first few days of
  birth
• Results in mental retardation/death
• Varying forms
• 1 in 185,000 infants
• Much higher prevalence in Amish

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What is MSUD?

• Urine has burning sugar/maple syrup odor
• Symptoms
• Vomiting, dehydration, lethargy, seizures,
  pancreatis
• Unable to process amino acids
• Leucine, isoleucine, valine
• Products build up, as well as their toxic
  by-products in blood and urine
• -If untreated, will lead to death, coma,
  neurological decline

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What genes are affected?

• BCKDHA (chr 19)
• Branched chain ketoacid
• dehydrogenase
• BCKDHB (chr 6)
• DBT (chr 1)
• DLT (chr 7)
• All work to create proteins for complex
• Autosomal recessive

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Testing

• Urine amino acid test
• Valine
• Children 17 to 37
• Adults 19 to 74
• Leucine
• Children 9 to 23
• Adults 20 to 77
• Isoleucine
• Children 3 to 15
• Adults 4 to 23
• Plasma amino acid test
• Chromatography
• Baby should not eat for 4 hours before