A 42-year-old man with dyspnea and clubbing has serum alpha-1 antitrypsin level of 18 mg/dL (normal 100-200 mg/dL). Liver biopsy shows PAS-positive, diastase-resistant globules within periportal hepatocytes. Electron microscopy of the liver would show material accumulated within which organelle?
- A Rough endoplasmic reticulum ✓
- B Mitochondria
- C Lysosomes
- D Peroxisomes
Correct answer: A. Rough endoplasmic reticulum
Explanation
Alpha-1 antitrypsin deficiency (PiZZ genotype) results in misfolded alpha-1 antitrypsin protein that accumulates as PAS-positive, diastase-resistant globules in the rough endoplasmic reticulum of periportal hepatocytes. Electron microscopy shows dilated ER cisternae containing the aggregated protein. The same deficiency causes panacinar emphysema due to unopposed elastase activity in the lung. Lysosomal accumulation is seen in storage diseases. Mitochondrial accumulation is not a feature of B1AT deficiency.
Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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