Metabolism USMLE Step 1 Practice Question
A 4-year-old girl presents with progressive gait instability and loss of speech over 6 months. Vital signs show BP 98/62, HR 102, RR 22, temp 37.2°C, SpO2 98%. Neurologic examination reveals spasticity, peripheral neuropathy, and absent deep tendon reflexes. MRI demonstrates diffuse CNS demyelination. Serum arylsulfatase A activity is markedly decreased. She denies recent infections and takes no medications. Which enzyme deficiency most likely explains these findings?
Answer choices
- ASphingomyelinase
- BHexosaminidase A
- CGalactocerebrosidase
- DArylsulfatase ACorrect answer
- EAlpha galactosidase A
- FGlucocerebrosidase
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