Ultrastructural studies in fetal I-cell disease.

The skin, brain, lung, liver, and kidney from a 20-week-old fetus who was diagnosed as having fetal I-cell disease by amniocentesis at 14 weeks of gestation were examined by light and electron microscopy. In addition, cultured fibroblasts from the skin were also observed microscopically. Cytoplasmic inclusions with dense polymorphic contents appeared commonly in the capillary endothelial cells in the skin, lung, glomerulus of the kidney, and the epithelial cells of proximal tubules of the kidney, and sometimes in the hepatocytes of the liver and the nerve and glial cells of the brain. Erythropoietic cells in the liver and circulating erythrocytes contained dense inclusions varying in developmental stages. Fibroblasts of the skin had several clear vacuoles, and cultured fibroblasts were filled with dense inclusions. The dense cytoplasmic inclusions in fetal I-cell disease were light and electron microscopically similar to the residual bodies which are commonly observed in the phagocytic cells.