Immunology USMLE Step 1 Practice Question
A 12-year-old girl presents with recurrent oral candidiasis, muscle cramps, and fatigue. Vital signs show HR 98/min, BP 102/68 mmHg, RR 16/min, temperature 37.2°C. Laboratory studies reveal serum calcium 7.2 mg/dL, elevated phosphate, and primary adrenal insufficiency with low cortisol. ACTH level is appropriately elevated. She denies immunosuppressive therapy or antiretroviral use. Which protein is most likely defective in this autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy syndrome?
Answer choices
- ABTK
- BCD40 ligand
- CFOXP3
- DAIRECorrect answer
- ERAG1
- FCIITA (MHC class II transactivator)
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