α1-Antitrypsin Deficiency and the PiMS Phenotype

We describe a premature infant with cholestatic liver disease and protease inhibitor MS phenotype. This infant demonstrated an abnormally low serum alpha 1-antitrypsin concentration. Liver histologic studies revealed diastase-resistant, periodic acid-Schiff-positive globules inside hepatocytes. Immunoperoxidase staining for alpha 1-antitrypsin was positive. Electron microscopy showed amorphous material in the dilated lumina of the endoplasmic reticulum. These findings are characteristic of alpha 1-antitrypsin deficiency. We suggest that this usually nonpathologic phenotype resulted in cholestatic liver disease because of the cumulative effect of several cholestatic conditions.