Manifestation of Infantile GM1 Gangliosidosis in the Fetal Eye. An Electron Microscopic Study

GM1 gangliosidosis in the infantile form is a rapidly fatal storage disease produced by deficiency of acid beta-galactosidase. Ultrastructural studies of the eyes from two fetuses affected with GM1 gangliosidosis were performed in an effort to assess tissue-specific distribution of storage inclusions in the different ocular components derived from neuroectoderm, surface ectoderm, and mesoderm. Two major configurations of inclusions were observed: electronlucent vacuoles and pleiomorphic osmiophilic membranes. Although the latter changes mainly affected the retinal neurons, they were occasionally found in cells of epithelial and mesenchymal origin. The findings indicate that the lysosomal storage process in GM1 gangliosidosis, type 1, has a wide morphologic spectrum that is already present in the early period of fetal life.