Inflammation and Immune Pathology USMLE Step 1 Practice Question
A 6-year-old boy presents with recurrent pyogenic infections and progressive neurologic decline. Vital signs show HR 102 bpm, RR 24/min, BP 98/62 mmHg, temperature 37.2°C. He exhibits nystagmus, partial oculocutaneous albinism, and distal peripheral neuropathy. Physical examination reveals no hepatosplenomegaly. Peripheral blood smear demonstrates giant granules within neutrophils. Serum immunoglobulin levels are normal. Which of the following chromosomal locus mutation best explains these findings?
Answer choices
- ADefect in C1 esterase inhibitor
- BDefect in lysyl oxidase
- CDefect in beta 2 integrin
- DDefect in microtubule trafficking with impaired phagolysosome fusionCorrect answer
- EDefect in NADPH oxidase
- FGriscelli syndrome from RAB27A or MYO5A mutations
See the full explanation
Get the correct-answer rationale, why each distractor is wrong, the underlying mechanism, and high-yield associations — plus adaptive practice that targets your weak areas — with a free MedBoardPRO account.