Molecular Biology/Genetics USMLE Step 1 Practice Question
A 2-month-old male infant presents with hypotonia, poor feeding, and seizures. Vital signs show HR 145 bpm, RR 38, BP 72/48, temperature 37.2°C, and SpO2 98% on room air. Physical examination reveals high forehead, flattened facies, and hepatomegaly. Laboratory studies demonstrate elevated transaminases (AST 156 U/L) and conjugated hyperbilirubinemia. Serum very-long-chain fatty acids are markedly elevated. The infant has no cardiac murmurs. This peroxisomal biogenesis disorder is most likely associated with which additional abnormality?
Answer choices
- ADeficient LDL receptor endocytosis
- BAccumulation of glycogen in lysosomes
- CDefective urea cycle function only
- DElevated very long chain fatty acidsCorrect answer
- EInability to metabolize galactose
- FImpaired synthesis of plasmalogens and bile acids
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