Maple Syrup Urine Disease
Also written as MSUD.
Maple syrup urine disease is an inborn error of metabolism of:
What our notes say
- Maple syrup urine disease is an inborn error of metabolism of: (Biochemistry End of Year Exam — 2014 (Past Paper))
- Specific features — unusual body odour (phenylketonuria — musty; maple syrup urine disease — sweet), abnormal hair/skin, developmental regression, cardiomyopathy (Chemical Pathology MCQs: Diabetes, Renal & Liver Disease)
Study material on Maple Syrup Urine Disease
Practice questions on Maple Syrup Urine Disease
Maple syrup urine disease involves accumulation of
- Phenylalanine and tyrosine
- Branched-chain amino acids
- Homocysteine
- Galactose-1-phosphate
Answer: B. Leucine, isoleucine, and valine accumulate due to deficient branched-chain alpha-ketoacid dehydrogenase, giving urine its characteristic sweet odor. ---
Maple syrup urine disease (MSUD) is caused by
- Deficiency of branched-chain alpha-ketoacid dehydrogenase → accumulation of leucine, isoleucine, valine
- Deficiency of homocysteine methyltransferase
- Deficiency of glucose-6-phosphatase
- Deficiency of galactose-1-phosphate uridylyltransferase
Answer: A. Autosomal recessive. Branched-chain amino acids (leucine, isoleucine, valine) accumulate → maple syrup odor of urine/cerumen. Leucine is most neurotoxic. Presents neonatally: poor feeding, vomiting, lethargy → cerebral edema → death if untreated. Treatment: BCAA-restricted diet + thiamine supplementation (some responsive). Leucine levels monitored closely.
Maple syrup urine disease involves accumulation of ---
- Phenylalanine and tyrosine
- Branched-chain amino acids
- Homocysteine
- Galactose-1-phosphate
Answer: B.
Maple syrup urine disease is caused by ---
- Fumaryl acetoacetate deficiency
- Branched chain α-keto acid dehydrogenase deficiency
- Branched chain α-keto acid dehydrogenase upregulation
- Decarboxylase deficiency
- Malonyl-CoA mutase deficiency
Answer: A.