Ultrastructural Studies in Fetal I-cell Disease

Abstract

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.

The ESCRT protein CHMP5 restricts bone formation by controlling endolysosome-mitochondrion-mediated cell senescence

“…is necessary for efficient fusion of late endosomes and lysosomes in MEFs 6 . Notably, the characteristics of TEM in Chmp5-deficient skeletal progenitors are similar to those of cells from human inclusion-cell disease, a lysosomal storage disease with defects in almost all lysosomal enzymes and manifesting bone, joint, and muscle problems 33,34 . As the endocytic pathway also participates in sorting and processing hydrolases during lysosomal biogenesis 35 , the perturbation of the endocytic pathway may affect lysosomal enzyme maturation and activation.…”