[Fucosidosis. Ocular ultrastructure]

Abstract

An ultrastructural study of the eyes of a six year old girl affected with fucosidosis demonstrated widespread overloading of lysosomes with a fibrillo-granular material of variable density. Conjunctival and corneal epithelial cells, keratocytes, sclérocytes, fibroblasts, corneal endothelial cells, retinal ganglion cells, inner segments of photoreceptors as well as glial cells of the optic nerve were markedly involved by the storage process. On the contrary, the pigment epithelium of the retina, the ciliary body and the iris were unaffected. Membranous cytoplasmic bodies were only disclosed within Schwann cells of conjunctival and ciliary nerves. Particularly striking lesions were observed within the endothelial cells of capillaries and veins of the eyes, as well as in all tissues examined, like the liver, spleen, kidney, lung, brain and skin. On the contrary, artery walls remained intact. These lesions explain the development of retinal vascular tortuosities, conjunctival aneurisms and cutaneous angiomas that characterize the clinical picture of our patient and that are often described in fucosidosis. The massive overloading of retinal ganglion cells contrasts with the absence of a macular cherry-red spot in fucosidosis. The nature of the stored material is probably responsible for this apparent discrepancy. Indeed, ganglion cells contain membranous cytoplasmic bodies in all diseases with cherry-red spots, whereas only a fibrillo-granular material was disclosed in the present case.