Electronmicroscopy of conjunctival biopsy in mannosidosis.

Electronmicroscopic examination was performed on conjunctival biopsies from two adolescent siblings with mannosidosis. Fibroblasts and endothelial cells contained membrane-bound vacuoles and vesicles that contained homogeneous osmiophilic globules. These vesicles seem to be pathognomonic of mannosidosis. Plasma cells also contained membrane-bound vacuoles, suggesting inhibition of the immunoglobulin production.