Juvenile amaurotic idiocy

Abstract

A patient with typical juvenile amaurotic familial idiocy of long duration was studied by cortical biopsy with regard to ultrastructure. A unique neuronal inclusion form, the principal body is composed of 2 major elements enclosed in a single tenuous membrane. Within the membrane are extremely electron-dense areas lyingin a somewhat less compacted matrix. The electron-dense areas are made up of concentrated membranes which often are paired. Frequently, a number of subunits are apparent in the dense areas, suggesting a combination of separate units. The other prominent feature of these bodies is the presence of one or more homogeneous, moderately dense vacuoles. Other inclusions, much less frequently observed, are similar to the membranovesicular and compound bodies reported previously. The ultrastructure of astrocytic inclusions suggests phagocytosis of the cytoplasm of degenerated neurons. This type of inclusion has not been reported in any other form of amaurotic idiocy. Abnormal membrane-enclosed lipid bodies were observed in both endothelial and perithelial cells of small cerebral blood vessels.