Chronic Kidney Disease USMLE Step 1 Practice Question
A 15-year-old boy presents with persistent microscopic hematuria discovered on routine urinalysis. He is hypertensive (BP 145/92 mmHg) with normal renal function (creatinine 0.9 mg/dL, eGFR 95 mL/min/1.73m²). His mother reports several male relatives developed progressive kidney failure in their teens. Physical examination reveals sensorineural hearing loss and anterior lenticonus bilaterally. He denies gross hematuria or edema. Which of the following is the most likely underlying defect?
Answer choices
- ADeficiency of nephrin
- BMutation of polycystin genes
- CMesangial IgA deposition
- DDefect in type IV collagenCorrect answer
- ESubepithelial immune complex deposition
- FThin basement membrane nephropathy from heterozygous COL4A3 or COL4A4 mutations
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