Corneal dystrophies associated with abnormalities of mucopolysaccharide metabolism.

Abstract

Certain heredofamilial corneal dystrophies may be considered to be either isolated abberations in mucopolysaccharide metabolism or local manifestations of related systemic processes. Recent histochemical and electron microscopical data have permitted better understanding of the former type of disorder, and recent techniques of chemical urinalysis have enabled construction of a new classification of the latter.1-5 Most mucopolysaccharides are composed of repeating and alternating units of hexuronic acid and a hexosamine. In macromolecular form, these polymers contribute to the formation of nonfibrous elements of connective tissue. They probably function in corneal deturgescence and also account for the normal metachromatic stainability of the substantia propria of the cornea. An abnormal histochemical appearance of the stromal mucopolysaccharides, on the other hand, is seen in hereditary macular dystrophy of the cornea (Groenouw's type II).6-9 Macular corneal dystrophy is not associated with any known systemic abnormality. Certain other heredofamilial syndromes, formerly considered to be