Chronic Kidney Disease USMLE Step 1 Practice Question
A full-term newborn presents with severe respiratory distress within 2 hours of birth. Vital signs show tachypnea (RR 68/min), tachycardia (HR 168/min), and hypoxemia (SpO2 88% on room air). Physical examination reveals bilaterally enlarged kidneys and hepatomegaly. Abdominal ultrasound demonstrates increased echogenicity of both kidneys with loss of corticomedullary differentiation and hepatic fibrosis. Serum creatinine is 2.1 mg/dL. There is no cardiac murmur on auscultation. Which diagnosis best explains this clinical presentation?
Answer choices
- AMutation of polycystin causing adult onset cortical and medullary cysts
- BMutation affecting fibrocystin leading to collecting duct cystic dilationCorrect answer
- CMutation of nephrin causing congenital nephrotic syndrome
- DDeletion of WT1 causing nephroblastoma
- EMutation of type IV collagen causing basement membrane splitting
- FMutation of aquaporin-2 causing nephrogenic diabetes insipidus with secondary renal dysfunction
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